mc6 - metro vancouver for exhibit 10, pa~e 19 of gvrd drinking water treatment and supply strategies...

Replacement for Exhibit 10, pa~e 19 of GVRD Drinking Water Treatment and Supply Strategies Report (March 11, 1994)

Water Treatment Decision Tree Rechlorinate

Select . - Position C Ch,oram'iate I Secondary DI~I~18ctlon Position B (THMS nol . . A ( 1994 DecIsion) ( THMS concern) r concern) Pos~on ~

• Upgrade Chlorine, 1994 Decision

Minimum Works

Required

Additional works to

meet standards Now or In the Future

Further Treatment

• not needed to meet

standards

Phase 1 Upgrade Chlorine, Corrosion Control and Chloramine

t Phase 2 *

Filter Seymour with Chloramine

t Phase 3 *

Filter Capilano with Chloramine

* Ozone as Primary

Disinfectant Filter Coquitlam with Chloramine

Phase 1 * Upgrade Chlorine, Corrosion Control

Phase 2 - Filter Seymour Phase 3 - Filter Capllano

- Filter Coquitlam 20 -30

Rechlorination Stations

* Ozone as Primary

Disinfectant and

Rechlorlnate

L

* Ozone is a primary disinfection option with filtration

Phase 1

Corrosion Control 45 - 60

Rechlorlnatlon Stations

t Phase 2 *

Filter Seymour with

Rechlorlnation

t Phase 3 *

Filter Capllano with Rechlorlnatlon

* Ozone as Primary

Disinfectant Filter Coquitlam

and Rechlorlnate

-

WI

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GVRD Drinking Water Treatment and Supply Strategies

January 1994

Prepared for:

Greater Vancouver Regional District Water Engineering and Construction Department

Prepared by:

Economic and Engineering Services, Inc. P.O. Box 1989 Bellevue, Washington 98009 (206) 451-8015

EI~ ECONOMIC AND ENGINEERING SERVICES, INC.

Mr. John Morse, P. Eng.

POBox 1989 • 12011 Bel·Red Rd • SUite 201 Bellevue. Washlng10n 98009

(20614518015· FAX 12061 451·8096

January 31, 1994

Manager, Water and Construction Greater Vancouver Regional District 4330 Kingsway Burnaby, B.C. V5H 4G8 Canada

File #

Re: Consolidation Report - Drinkin~ Water Treatment and Supply Strate~ies

Dear Mr. Morse:

The enclosed final report summarizes the findings of numerous technical reports and studies and several years of research and effort by the Greater Vancouver Regional District (GVRD) staff and outside specialists on water supply issues.

The GVRD faces some major decisions in the immediate future related to drinking water treatment, additional water supply, and dam safety. We trust that this report will facilitate making the best long range choices for the region's water supply.

GJK:smn Enclosure

Olympia. WA

Sincerely,

ECONOMIC AND ENGINEERING SERVICES, INC.

~I/~ Gregory J. Kirmeyer, P.E. Vice President

Bellevue. WA Vancouver. BC Portland OR Washington. DC

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GVRD Drinking Water - Treatment and Supply Strategies

Drinking Water Treatment and Supply Strategies At a Glance

WHAT Is THIS REpORT ABOUT?

This report summarizes several years of study and numerous reports into a concise document to help the GVRD address some pressing water treatment and supply issues.

WHAT ARE THE ISSUES?

The major issues are:

o GVRD drinking water quality does not meet the British Columbia Health Act or the Canadian Drinking Water Quality Guidelines. The region's Medical Health Officers are recommending compliance as soon as possible.

o Current source capacity is only adequate through year 2005 - at which time either expansion of the present sources or a new source of supply will be needed.

o Seymour Falls Dam does not meet modem earthquake standards and provincial authorities have ordered action.

These issues are all interrelated and should be addressed in a comprehensive rather than piecemeal manner.

WHAT DECISIONS NEED To BE MADE?

The major decisions facing the GVRD and the region are embodied in these four questions.

1. Should the GVRD use rechlorination (higher chlorine levels) or chloramination to provide a secondary disinfec-

tant residual throughout the water distribution system?

2. What is the next source of supply -should the GVRD expand the supply from Seymour or from Coquitlam?

3. Does the GVRD simply upgrade Seymour Falls Dam to make it safe; or build anew, higher dam, and at the same time provide an expanded Seymour source?

4. How quickly should the GVRD move toward filtration and which sources should be filtered first?

WHAT ARE THE MAJOR QUALITY

AND TREATMENT ISSUES?

The major water quality problems relate to (1) the potential for disease, i.e., Giardiasis (beaver fever) from the source waters; (2) the growth of bacteria in the GVRD and municipal piping systems and lack of disinfectant residual; (3) periodic turbidity (cloudiness) in the water; and (4) corrosion of building plumbing, especially copper. Simply stated, although the water is safe, it does not meet the B.C. Health Act and Greater Vancouver is the only major centre in Canada that does not meet all the Canadian Drinking Water Quality Guidelines; therefore, the potential for waterborne disease is a concern. GVRD studied these problems and adopted the Drinking Water Quality Improvement Plan in 1990 that included phased, conceptual solutions. Subsequent to that, planning and predesign studies and an Environmental Impact Assessment were conducted to refine

the program. By far, the most controversial aspect of the program is secondary disinfection.

WHAT Is SECONDARY DISINFECTION?

Secondary disinfection refers to the ability of the water to carry a disinfectant residual throughout the GVRD and municipal piping systems. A residual is necessary to prevent bacteria from growing in the piping and to protect against the inadvertent entry of contamination into the system. Based on exhaustive study, the only two feasible choices for secondary disinfection are chloramination and rechlorination (higher chlorine levels). Both are used extensively throughout North America. Chloramination is more effective, tastes less chlorinous, and is less expensive than rechlorination; however, chloramines are more persistent and, when released to sensitive streams, can kill fish before the chloramine is diluted and dissipates. The potential for significant legal penalties is much greater if chloramines are selected. Mitigation practices proposed for chloraminated water discharges significantly lower the impact, but are not expected to reduce the risk to the same level as re-

o •

chlorinated water. The region's Medical Health Officers support chloramination because it has greater public health benefits. Environmental government agencies and certain environmental groups support rechlorination because its potential to kill fish is much less than with chloramination.

Ozone was investigated and found to be not suitable as a secondary disinfectant because it's residual lasts only a few minutes. However, it is suitable as a primary (at the source) disinfectant and could be used in the future instead of chlorine, if desired. Where ozone is used in water systems, it is normally with filtration and is followed by a chlorine-based secondary disinfectant.


ii

WHA T ARE THE CHOICES FOR THE

NEXT SOURCE OF WATER SUPPLY?

An additional supply of water is needed by 2005 or the region will begin to experience increasing shortages of water to meet the demand of a growing population. Given the rapid growth in the region, even a vigorous water conservation program would delay this date only a few years. The existing and other surface water sources, such as the Fraser River, as well as groundwater were evaluated. The choices have been narrowed to expansion of existing sources -- Seymour or Coquitlam. Seymour will require anew, higher dam to impound more water, and Coquitlam will require extensive negotiation with B.C. Hydro to ultimately phase out the present use of the water for power generation. One of these sources will be needed very soon.

WHAT CAN BE DONE To MAKE

SEYMOUR FALLS DAM SAFE?

To address safety concerns related to an earthquake, two choices are available. The existing Seymour Falls Dam can be upgraded; or anew, earthquake proof, higher dam can be constructed as part of new source development. A new dam will result in the immediate need for filtration of Seymour to remove sediment associated with dam raising.

From a reliability standpoint, it would be better to build a new dam at Seymour rather than upgrade the old one, because then the water supply intake could also be improved to make it withstand an earthquake as well.

WHAT OPTIONS WERE EVALUATED To

BEST SOLVE ALL PROBLEMS

SIMULTANEOUSLY?

The GVRD has developed six options to solve these problems. Two of the options

use chloramination and four use rechlorination. The two future supply options are Seymour and Coquitlam, although both are eventually needed. The alternatives for a safe darn are to upgrade the existing Seymour Falls Dam or build a new one.

To evaluate the options, these five criteria were used: (1) adequate supply and dam safety; (2) high water quality and compliance with guidelines; 3) environmental issues related to secondary disinfection; 4) flexibility for phasing to reduce cost; and 5) costs. Each option has benefits and drawbacks as the report discusses.

CAN THE DECISIONS BE DEFERRED

ANY LONGER?

No, the GVRD has adequate information and needs to move forward. The reasons that decisions are needed in 1994 are:

o Medical Health Officers have recommended bringing the drinking water quality into compliance with guidelines and the B.C. Health Act as soon as possible. Deferral will result in a continuing status of noncompliance and potential for waterborne disease.

o Based on the long lead time to plan, design, and construct a new darn at Seymour, or to negotiate with B.C. Hydro for more Coquitlam water, a decision is needed now. Deferral will result in acute water shortages in the future.

o The Province requires the GVRD to act to bring Seymour Falls Dam into compliance with modem earthquake standards as soon as possible.


iii

WHAT ARE THE NEXT STEPS?

The first step is to select which secondary disinfectant should be used. That choice then dictates how quickly GVRD needs to move towards filtration. If chloramination is selected, phasing of filtration is possible. Seymour and/or Capilano filtration could begin within the next ten years, or they could be delayed further into the future. If rechlorination is selected, a commitment to immediate filtration of all sources is likely needed. The choice of which source to develop first, Seymour or Coquitlam, can then be made more clearly. Seymour requires a significant capital investment; whereas, Coquitlam requires negotiation with B.C. Hydro for more water. Both sources will eventually be needed. The method for addressing the dam safety issue hinges on the choice for the next source of water.


Table of Contents

At a Glance ...................................................................................... i

Purpose ........................................................................................... 1

Overview of Major Drinking Water Issues Facing GVRD .................................................................................. 1

Approach and Consultation Process ...... : ........................................ 2

Water Treatment Issues .................................................................. 3

Secondary Disinfection .................................................................... 6

Water Supply Issues ......................... .............................................. 8

Seymour Falls Dam Safety Issue .. ................................................ 10

Merging of Three Major Issues ...................................................... 10

Benefits and Drawbacks of Options .............................................. 12

Decisions That Need to be Made .................................................. 15

Conclusions ................................................................................... 17

Appendix A - Drinking Water Quality Improvement Plan ............. A-1 Appendix B - Future Water Supply ..................... ......................... B-1 Appendix C - Seismic and Dam Stability - Seymour Falls Dam .. C-1

Responses to Commonly Asked Questions and Public Concerns .......................................................................... Q-1

Glossary of Terms and Abbreviations ......................................... G-1

List of Reports ............................................................................. R-1


List of Exhibits

Exhibit 1 Water Quality Problems ................................................ 3

Exhibit 2 Comparison of Rechlorination and Chloramination ............................................................. 6

Exhibit 3 GVRD Water Consumption Projections ........................ 8

Exhibit 4 GVRD Water Supply Alternatives ................................. 9

Exhibit 5 Greater Vancouver Regional District - Source and Seymour Dam Seismic Decision Tree ............................................................. 10

Exhibit 6 Elements of Options to Solve Problems ..................... 11

Exhibit 7 Evaluation Criteria ...................................................... 12

Exhibit 8 Summary Comparison of Options ............................... 13

Exhibit 9 Water Quality Compliance vs. Costs .......................... 15

Exhibit 10 Water Treatment Decision Tree .................................. 19

Purpose is to merge three initiatives.

GVRD faces three major issues:

• Water quality • Water source • Damsafety


Summary

Purpose

The purpose of this Summary Report is to merge three major initiatives currently being pursued by the Greater Vancouver Regional District (GVRD) into a single document to facilitate decisions by the Greater Vancouver Water District (GVWD) Board of Directors. The three initiatives are (1) the Drinking Water Quality Improvement Plan, (2) portions of the Comprehensive Regional Water Supply Study, and (3) the Seymour Falls Dam Safety Issue.

This merged report will enable decision makers to concurrently evaluate and select future improvements to best address all water quality, source of supply, and dam safety concerns. Each of these initiatives is summarized briefly in this Summary Report with more information provided in subsequent Technical Appendices (Appendix A - Drinking Water Quality Improvement Plan, Appendix B - Future Water Supply, and Appendix CSeismic and Dam Stability are not contained in the condensed report). This document is based on and consolidates over 20 major reports that are listed in the back of the report.

Overview of Major Drinking Water Issues Facing GVRD

The GVRD supplies an average of 1.1 billion litres per day of drinking water to over 1.6 million people in the Greater Vancouver area through 18 municipal entities. The utility draws water from three major water source reservoirs - Capilano, Seymour, and Coquitlam, and has 19 large distribution reservoirs, three chlorination treatment stations, and over 500 km of pipe. In operating these facilities and supplying this water, the GVRD has to balance various competing needs and resources. The goals are to provide adequate supply and transmission facilities to meet the region's drinking water needs for both the near and long terms (50 years) and to ensure that the water consistently meets the British Columbia Safe Drinking Water Regulation and the Canadian Drinking Water Quality Guidelines. In meeting these goals, the GVRD considers cost, health standards, environmental concerns, safety issues, plus other criteria.

Among the major issues facing the GVRD in the immediate future are these three:

o The water is considered safe, but the quality of the water does not consistently meet all the applicable standards and as a result the

1

Board needs to answer these four questions:

Question 1

Question 2

Question 3

Question 4

GVRDhas conducted technical studies and public consultation.


potential for waterborne disease exists. Consequently, the region's Medical Health Officers have recommended that GVRD bring the quality of the water into compliance as soon as possible.

o Water sources currently on-line will not meet increasing water demands past the year 2005, thus additional water is needed soon, especially considering the long lead time required to expand the existing sources or develop a major new source of supply.

o Seymour Falls Dam does not meet current earthquake standards and the Province has ordered remedial action as soon as possible to bring it into conformance with modem standards.

The importance of the decisions relating to these issues is emphasized by the large range of capital costs from $302 to $1,251 million depending on the option selected.

In facing these issues, the region and the Board will need to answer these four questions:

Should the GVRD use rechlorination (higher chlorine levels) or chloramination to provide a secondary disinfectant residual throughout the water system?

What is the next source of supply - should the GVRD expand the supply from Seymour or from Coquitlam?

Does the GVRD simply upgrade Seymour Falls Dam to make it safe, or build anew, higher dam and in so doing provide an expanded Seymour source?

How quickly should the GVRD move toward filtration and which sources should be filtered fIrst?

Approach and Consultation Process

The GVRD has embarked on an approach consisting of these two elements to answer the questions posed above - (l) technical studies, and (2) a consultation process involving governmental agencies and the general public including a citizen's advisory committee. Technical studies on the water quality have been ongoing since 1987, and in 1990, the GVRD formally adopted the Drinking Water Quality Improvement Plan (DWQIP). GVRD staff and consultants, in cooperation with municipal staff, have also been developing a Comprehensive Regional Water Supply Study to set out improvements to water sources and transmission facilities needed for the coming decades. Likewise, studies to evaluate methods and

2


costs to bring Seymour Falls Dam and other facilities into compliance with modem earthquake standards have been developed. All of these technical studies are sufficiently complete to enable the major policy decisions listed above to be addressed before proceeding further with siting and more detailed design work. Concurrent with the technical studies, there has been significant municipal and public involvement including a citizen's advisory group, especially focused on the DWQIP and the controversy surrounding the decision on which secondary disinfectant to use; chlorine or chloramine. Public consultation will continue in early 1994.

Water Treatment Issues

Exhibit 1 Water Quality Problems

The GVRD has identified the four water quality concerns listed in Exhibit 1. Greater Vancouver is the only major centre in Canada whose water does not consistently meet the Canadian Drinking Water Quality Guidelines. While GVRD water is considered safe, it does not currently comply with all existing standards, and so the potential for waterborne disease exists. The region's Medical Health Officers have recommended improved compliance as soon as possible.

Concern Why

Waterborne Cysts are often Disease detected in the (Giardiasis water system at potential) low risk levels.

Coliform Bacterial levels are Bacteria too high; occur-

ence exceeds stan-dards; disinfectant depletes along system.

Turbidity Often too high. (Cloudiness) especially in

Capilano and Seymour.

Corrosive Natural acidity Water causes corrosion of

metal pipes and faucets.

GVRD studied ozone and filtration.

Solution

Kill the cysts with a primary disinfectant at low turbidity and remove them with filtration at higher turbidity.

Provide secondary disinfectant - either chlorine or chloramine throughout the system.

Shut down the turbid source or filter the water.

Raise the pH of the water.

DWQIP Response

Phase I - Use Chlorine Disinfectant.

Phase II - Filter Seymour.

Phase III - Filter Capilano.

Phase I - Rechlorinate or Chloraminate.

Phase I - Shut down one source and use Westerly Transfer - Interim Solution Only.

Phase II - Filter Seymour.

Phase III - Filter Capilano.

Phase I - Add minerals to reduce corrosion.

To work towards bringing the water into compliance, the GVRD adopted the three phased Drinking Water Quality Im-provement Plan in 1990. Since

1990, considerable investigation has been undertaken in the following areas:

o Ozone and filter pilot plant studies indicating that direct filtration is feasible, and that ozone may also have potential benefits in the long-term as a primary disinfectant when combined with filtration,

o Siting studies for treatment facilities culminating in a plan to consolidate filter plants for Capilano and Seymour near Rice Lake, and

3

Environmental Impact Assess-ment of second-ary disinfection completed.

Chlorine and chloramine are the only feasible "secondary" disinfectants.

Ozone does not provide a long lasting residual.

More details on water treatment may be found in Appendix A.


o Environmental Impact Assessments for evaluating the impacts of rechlorination and chloramination on fish bearing streams.

By far, the most controversial aspect of the DWQIP is associated with the need for and choice of a secondary disinfectant. There is no question in the minds of health authorities that the GVRD water must have a disinfectant residual throughout the municipal distribution systems to maintain water quality (secondary disinfection). Presently, the chlorine residual in eighty percent of the municipal distribution systems is too low to control bacteria in the pipes. Meeting bacteria standards is required by law through the B.C. Health Act. Consultants for the GVRD evaluated several methods for providing secondary disinfection, including rechlorination (higher chlorine levels), chlorine dioxide, chloramination, ultraviolet light, potassium permanganate, and ozone. Treatment methods including filtration and biological filtration were also evaluated. The only two feasible alternatives for secondary disinfection and residual maintenance (!Ie rechlorination and chloramination, both of which have been in use in North America and Europe for over 75 years. Increased water system maintenance (cleaning and flushing) will aid but not replace secondary disinfection. In the case of a water main discharge, both chlorine and chloramine are toxic to fish, but chloramine is much slower to breakdown in the environment, and as a result, has a much greater potential to kill fish.

Ozone was considered in great detail as a primary disinfectant and is feasible only if combined with source filtration. It is not suitable as a secondary disinfectant because it does not maintain a residual beyond a few minutes. Where ozone is used in other water systems, it is normally used with filtration and is followed by a chlorine-based secondary disinfectant.

The result of all of this work is the following staged program to meet the standards.

Non-Filtration (Phase I DWQIP)

o Improved primary chlorination facilities would be added at all three supply sources to help inactivate possible Giardia cysts. These facilities, including construction of an innovative V-shaped tunnel eastward from Capilano towards Rice Lake, would provide sufficiently long contact times to kill the cysts at low turbidity.

o Secondary disinfection to control bacteria levels and to provide continuing disinfectant protection throughout municipal systems would be achieved through the addition of a chlorine ammonia substance known as chloramine at three source treatment facilities,

4

-

-

Phase I provides significant improvement in compliance.

Phase II meets almost all standards.

Phase III virtually meets all standards.


or the addition of chlorine at a series of up to 60 rechlorination stations spread throughout the region.

o A pipeline and associated pumping stations (the Westerly Transfer) would be built to transfer water from the Coquitlam reservoir into either the Seymour or Capilano distribution systems, but not both at once, during periods of high turbidity at the westerly sources.

o Significant corrosion of metal plumbing pipes, particularly copper, would be reduced by raising the pH and alkalinity levels through addition of natural minerals.

Effectiveness. Phase 1 would bring regional drinking water from the estimated present 50 percent compliance level to about 80 to 90 percent compliance with Canadian Drinking Water Quality Guidelines if chlorarnination is chosen, or 70 to 80 percent compliance with future guidelines if rechlorination is selected. Phase I would solve bacteria and corrosion problems. While it would reduce the threat of Giardiasis and the occasional turbidity event substantially, it would not eliminate those concerns completely. The Westerly Transfer should only be considered a short-term option and most useful between now and about 2015. Beyond that point, because of growth in water demand, the effectiveness of the transfer approach becomes much more limited.

Filter Seymour (Phase II DWQIP)

A filtration plant on Seymour would be built near Rice Lake further reducing turbidity in water distributed to municipalities in this service area.

Effectiveness. Filtration of the Seymour source, possibly sited at Rice Lake, coupled with chlorarnination in Phase I would bring the water to about 95 percent compliance. Because of increased disinfection byproducts, the rechlorination option would result in slightly lower compliance. Water from the Capilano reservoir would still have some vulnerability to Giardiasis during periods of high turbidity. Phase IT would have a major beneficial effect on reducing turbidity system-wide if pursued in conjunction with the Westerly Transfer component of Phase I.

Filter Capilano (Phase III DWQIP)

The Seymour filtration plant site would likely be expanded to accommodate the filtration of Capilano to further reduce turbidity in water distributed to municipalities in its service area. To accomplish this, Capilano water would be pumped through an extension of the U tunnel constructed in Phase I, to an expanded filtration plant at the Rice Lake site.

5

Rechlorination could result in the need to filter Coquitlam.

Chloramine is a better disinfec-tant, but poses a greater potential threat to fish than chlorine.


Effectiveness. Filtration of the Capilano water combined with the chloramination option would bring the water up to virtually 100 percent compliance. The rechlorination option would provide a slightly lower compliance.

Filter Coquitlam (Not included in three phases of DWQIP)

Filtration of Coquitlam was not originally included in the Drinking Water Quality Improvement Plan because of its historical low turbidity and high water qUality. However, tightening of the water quality guidelines, specifically regarding disinfection by-products, coupled with a rechlorination option for secondary disinfection could result in the need for filtering Coquitlam to remove disinfection by-product precursors (natural organics) in the future.

Secondary Disinfection

A demonstration project in Surrey serving 70,000 people has been operating since 1988 comparing the rechlorination and chloramination options (Exhibit 2). Based on drinking water quality and health issues, chloramination is preferred. It is more effective at controlling the extensive bacterial regrowth problem, less expensive, tastes better,

Exhibit 2 requires fewer treat-Comparison of Rechlorination and Chloramination ment sites, and can be

Rechlorination

Drinking Water Fair to Good. (Health) Guidelines May trigger filtration in near

term to control THMs.

Environmental Nil to severe depending on conditions - DFO prosecution potential is low.

Aesthetic Taste/Odor Chlorinous taste.

Costs

Capital $40 - $50 million.

Annual Oper. & $3 - $5 million. Maint.

Filtration $360 million more for filtering Coquitlam.

Mitigation for Significant. Discharge to Surface Water

Implementation 8 - 10 years.

50 - 60 rechlorination stations throughout region.

Chloramination

Good. Filtration not required for Phase I DWQIP for THM control.

1 to 20 times the impact of re-chlorination. DFO prosecu-tion potential - high as some fish kills will undoubtedly occur.

Almost no taste.

$1 - $2 million.

$0.5 - $0.6 million.

Filtering Coquitlam not required.

More significant - $10 million more capital cost allowance provided.

3 years.

3 chloramination stations at sources.

6

implemented faster. Both rechlorination and chloramination will meet the B.C. Safe Drinking Water Regulation but chloramination will be more effective for control-ling bacteria.

The major drawback is that chloramines are more persistent in the environment and they do not dissipate as rapidly as chlorine if discharged to streams and lakes. In the first two years of a five year period of operation in Surrey, two separate fish kills in Fergus

-

Survey of recovery of Fergus Creek is inconclusive.

Technical consensus on Environmental Impact Assess-ment is reached.

Allowable levels for disinfection by-products are being lowered by health agencies.


Creek have been attributed to inadvertent chloramine discharges associated with water main breaks. A 1993 ecological survey of Fergus Creek indicated the presence of numerous fish and fish food organisms, which may be similar to the prespillievel. In the absence of prespill data, the determination of whether full recovery has occurred is inconclusive. The GVRD has undertaken a major effort in a three stage Environmental Impact Assessment (EIA) to document the environmental impacts of rechlorination and chloramination. GVRD consultants, Department of Fisheries and Oceans (DFO) , Environment Canada, and Ministry of Environment (MOE) have reached a consensus on the reports for their technical assessment of the environmental consequences of rechlorination versus chloramination. Potential for fish kills can be minimized for both chloramination and rechlorination, but not eliminated. Mitigation practices, such as dechlorination units for more sensitive streams and other procedures, proposed for chloraminated water discharges significantly lower the impact, but are not expected to reduce the risk to the same level as rechlorinated water. There is a greater potential for more significant penalties from DFO charges associated with chloramination than rechlorination.

The major drawback to rechlorination is that it will form significantly higher disinfection by-products, notably trihalomethanes (THMs) and haloacetic acids (HAAs), than chloramination. Both THMs and HAAs are suspected carcinogens, as det~rmined by tests on laboratory animals at high dosages. Consequently, an interim level of 100 parts per billion (ppb) has been set for THMs in the Canadian Drinking Water Quality Guidelines. Fifty ppb for THMs was earlier proposed and may be reconsidered. Guidelines for HAAs are being considered at this time by health authorities.

The interim level for THMs proposed in the USA is 80 ppb, with the potential for a 40 ppb level within 10 years. Health Canada will evaluate health information as it becomes available and may set lower levels in Canada as welL It is anticipated that rechlorination, based on pilot testing, can just barely meet the interim 100 ppb level without filtration and could exceed it in some areas of the system. Any THM level set lower than 100 ppb or a low level for HAAs will trigger the need for filtration of all three sources to meet potential future standards with rechlorination. The uncertainty with regards to future THM guidelines and their probable carcinogenic properties were part of the reasons why the Medical Health Officers support chloramination. Chloramination can meet the interim 100 ppb THM level with a wide margin of safety and can also meet a future standard of 50 ppb.

MOE prefers rechlorination because of its much lower potential for environmental impact. The Medical Health Officers prefer chloramination for improved health benefits including lower THMs.

7


Water Supply Issues The water supply issues of most importance relate to the next source of supply and to the safety of Seymour Falls Dam. As depicted in Exhibit 3,

even with a basic water Annual Average Consumption (MUday) conservation program, the

existing GVRD sources will 3.000 .--------------------,

2.500 not meet growing water

New Source Needed Here in Year 2005

demands past 2005. With the long lead time required to bring a new expansion of supply on-line, decisions regarding the next source and related water conservation programs are needed now.

2.000

Current Source Capacity

1.500

1.000

500

Through the work conducted o~~_~-L~_L-~~~_~-L~_L-~~_~

1966 1971 1976 1981 1986 1991 1996 2001 2006 2011 2016 2021 2026 2031 2036 2041 in the Comprehensive Regional Water Supply Study, a range of alternative future sources of supply were inves-

Year

Exhibit 3. GVRO Water Consumption Projections

New source options have been narrowed to Seymour and Coquitlam.

More details on water supply maybefound in Appendix B.

tigated, from tapping and treating the Fraser River to expanding existing sources, and many other options in between including development of groundwater. This screening exercise determined that the most cost-effective source for the next supply increment is expansion of one of the three existing sources. Upon further review it became apparent that Capilano was the least favoured option due to the difficulty in siting a new dam and the fact that the water demand centre is shifting towards the east, away from Capilano. Thus the choice of alternatives was narrowed to Seymour or Coquitlam.

To gain more water, two options are available. GVRD can build a new, higher Seymour Falls Dam first for a cost of up to $90 million and then negotiate with B.C. Hydro for more Coquitlam water when needed (refer to top of Exhibit 4 on the next page). Conversely, GVRD can first fully utilize Coquitlam and, at a date beyond the 50 year planning horizon, follow that by expanding Seymour with construction of anew, higher dam (refer to bottom of Exhibit 4 on the next page). This option assumes that operational flexibility requirements do not require construction of a new Seymour Dam before full utilization of Coquitlam Lake is reached, which may not be the case. Full use of Coquitlam would involve extensive negotiations with B.C. Hydro to determine compensation for the loss of power generating capability at the Buntzen power generating facilities. The preliminary analyses of the two options concluded that neither option presented any clear financial advantage over the other.

8

.-


First Source is Seymour, Followed by Coquitlam - Options 1,3 and 5

3,000

2,500

Projected Demand

1,500

Present Available Supply

1,000 ~--~~--~--~--~----~--~--~----~--~--~

1991 1996 2001 2006 2011 2016 2021 2026 2031 2036 2041 Year

First Source is Coquitlam, Followed by Seymour - Options 2, 4 and 6

3,000

Planning, Design and Construction

2,500 Full Coquitlam

Coquitlam

Projected Demand

1,500


1,000 ~----~--~--~--~----~--~--~----~--~--~ 1991 1996 2001 2006 2011 2016 2021 2026 2031 2036 2041

Year

Exhibit 4. GVRO Water Supply Alternatives

9

Seymour Falls Dam is not in compliance with modern earth-quake standards.

More details on dam safety may be found in Appendix C.

Water quality, water supply, and dam safety are all interrelated.


Seymour Falls Dam Safety Issue

Seymour Falls Dam does not comply with modern standards for earthquake resistance set by the Ministry of Environment's Dam Safety Branch. Thus, remedial actions are needed to either repair the existing dam or build a new one as part of a new source development program.

Based on the GVRD's experience following construction of both Cleveland and Seymour Falls Dams, it is expected that construction of anew, higher dam at Seymour Falls would result in an increase in turbidity when the reservoir is filled. Based on records that show elevated turbidity readings following completion of the present dams, and the experiences at other similar developments, the increase in turbidity is expected to last 5 to 10 years as the newly flooded lands stabilize. Turbidity levels previously acceptable in the 1950s and 1960s are not acceptable by either the current health standards or the public. Since it cannot be assumed that such turbidity would occur only in the low demand season when the intake could be shut off, a filtration plant would be needed in conjunction with the new dam.

Merging of Three Major Issues

Water quality improvement, selection of the next water source, and dam safety are all interrelated as shown on Exhibit 5, and merging of these key issues is necessary to ensure that overall GVRD water supply objectives

are met. Exam

.----..:::.C=hlo:::.:ranu=.na==te~_s_eC_Ondary __ Di_·si_n~_eC_tiO_n_Dec_i_sio-n .... l~ ples of the interrelationships are as follows:

o~g~r~:l Seymour

Seymour Filtration

Plant

New Dam at Seymour

Falls

Ultimately Fully Utilize Coquitlam

o~g~::,:z Coquitlam

Upgrade Seymour Falls Dam

Fully Utilize Coquitlam

YOr Disinfectant By-Products

~N' a Concern? , +

, +

o~g~~:3 o~g~::,~ 0gg~::,:5 0gg~::,:6 Seymour Coquitlam Seymour Coquitlam

Filter All Filter All Seymour Upgrade Seymour Sources Sources Filtration Falls Dam

Plant New Dam at Upgrade Seymour New Dam at

Fully Utilize Seymour Falls Dam Seymour

Coquitlam Falls Fully Utilize Falls 45 -60

20-30 Coquitlam Rechiorination

Rechlorination 30-50 Stations

Stations 20- 30 Rechlorination Rechlorination Stations

Ultimately Stations Fully Utilize Ultimately Coquitlam Fully Utilize

Coquitlam

Exhibit 5. Greater Vancouver Regional District· Source and Seymour Dam Seismic Decision Tree

10

Construction of a new dam on the Seymour source will trigger filtration of Seymour because construction related turbidity for a period of 5 to 10 years will be unacceptable. If rechlorination is chosen as the secondary disinfectant, and the THM guideline

Six options have been developed.

Options 1 and 2 are based on chloramination.

Options and Se(:ondary

Disinfectant

Chlorarnination Option 1

Chlorarnination Option 2

Rechlorination Option 3





is subsequently reduced from 100 ppb to 50 ppb, filtration of all sources will be required to meet the reduced level. Comprehensive repairing of the existing Seymour Falls Dam may not be required if Seymour is the next source of supply and anew, higher dam is constructed in the immediate future.

Based on the key issues facing GVRD and their interrelationships, six options have been developed for further evaluation (Exhibit 5). All options assume that at least Phase I of the Drinking Water Quality Improvement Plan will be implemented to make the water comply with the B.C. Health Act.

Phase 1 includes transmission improvements (the Westerly Transfer) to enhance interchange of source waters, secondary disinfection (rechlorination or chloramination), primary disinfection to address Giardia, and corrosion control. Further, the two sources evaluated for additional water are expanded use of Seymour and Coquitlam. If Seymour is selected as the next source, earthquake concerns will be addressed by a new dam. If Coquitlam is selected, the existing Seymour Falls Dam will be upgraded.

Because of the costs and health implications, drinking water quality should be the driving force in the decision process. Once decisions about secondary disinfection have been made, the next source of supply can be more readily determined.

Exhibit 6 Elements of Options to Solve Problems

Next Source Water Quality (year needed) and Treatment

Seymour (2005) Phase I plus filter

Coquitlarn (2031) Seymour (Phase II)

Coquitlarn (2005) Phase I

Seymour (2005) Phase I, II, III, plus filter Coquitlarn

Coquitlarn (2031) 20 - 30 rechlorina-tion stations

Coquitlarn (2005) Phase I, II, III pi us filter Coquitlarn

20 - 30 rechlorina-tion stations

Seymour (2005) Phase I plus filter

Coquitlarn (2031) Seymour (Phase II)


Coquitlarn (2005) Phase I


11

Upgrade or Build New

Seymour Dam

Build new, higner darn

Upgrade darn

Build new, higher darn

Upgrade darn

Build new, higher darn

Upgrade darn

The elements of the six options are outlined in Exhibit 6. Options 1 and 2 assume chloramine is used and that filtration of all sources is not needed specifically because disinfection by-products are less than proposed standards. Filtration to reduce existing natural turbidity patterns can be addressed after one of these options is selected. Filtration is needed for control of turbidity associated with new dam construction on Seymour.


Rechlorination Options 3 and 4 assume future lowerTHM standards are a concern.

Options 3, 4,5, and 6 assume rechlorination is used and provide choices of both Coquitlam and Seymour as future sources. Options 3 and 4 are forward looking and are based on the premise that THMs are presently and will remain a significant issue. In addition, they assume that future THM standards will be lower than the interim 100 ppb level and that standards for HAAs will be established. These options also include filtration immediately to enable the GVRD to meet present and future THM standards, which is consistent with the Medical Health Officers' concerns.

Rechlorination Options 5 and 6 assume THM standards are not a concern.

Options 5 and 6 are based on the premise that THMs and other disinfection by-products are not major concerns and that the permanent level for THMs will remain at the interim level of 100 ppb. This is just the opposite of Options 3 and 4. The trend in the USA and Europe is to move towards lower standards for disinfection by-products and Canadian standards are expected to follow this trend.

1.

2.

3.

4.

5.

Benefits and Drawbacks of Options

Exhibit 7 Evaluation Criteria

Adequate Supply and Dam Safety

0 Does the alternative meet the future water supply needs at the 98% reliability, i.e., assumes shortage only once every 50 years?

0 Does the alternative address modem day safety standards and meet Provincial seismic standards as weII as reliability objectives?

High Water Quality and Meet Guidelines

0 Does the alternative significantly improve water quality?

0 Will the water meet the latest Canadian Drinking Water Quality Guidelines now and in the future?

0 Can the alternative be phased to add treatments to meet possible future Canadian Guidelines?

Environmental - Related to Secondary Disinfectant

0 Does the alternative have a high or low potential for adversely impacting the fishery resource?

0 Does the alternative have a high or low potential for incurring a legal challenge and/or fines from DFO?

Flexibility for Phasing

0 Does the alternative maintain flexibility in terms of phasing to reduce the initial cost impacts?

Costs

0 What are the capital costs?

0 What are the annual operating and maintenance costs?

0 What is the Net Present Value?

12

The alternatives were evaluated in terms of five major criteria as depicted by Exhibit 7. As indicated in Exhibit 8 on page 13, which summarizes the evaluation process, all of the options will meet the dam safety concerns related to Seymour Falls Dam. Reliability of the Seymour source remains an issue if the dam is upgraded instead of replaced. A major concern is that the present water intake structure could still be damaged by an earthquake to the point where it would be inoperable. Thus, the dam would not fail, but the ability to deliver water into the water system could be severely impaired. Although considered in detail, no practical solution to address this concern has been

...... V-l

~

Exhibit 8 Summary Comparison of Options

Elements of Options Canadian Water Adequate Quality Guidelines Environmental

Options and Upgrade or Supply Related to Secondary Water Build New and Dam Secondary

Disinfectant Next Source Treatment Seymour Dam Safety Present Future Disinfection

Option 1: Seymour Phase I and II New Dam

Chloraminate (2005) • • • 0 Coquitlam (2031)

Option 2: Coquitlam Phase I Upgrade Dam

Chloraminate (2005) • • f) 0

Option 3: Seymour Phase I, II, III, New Dam

Rechlorinate (2005) plus filter Coquitlam • • • • Coquitlam 20 - 30 rechlori-

(2031) nation stations

Option 4: Coquitlam Phase I, II, III, Upgrade Dam

Rechlorinate (2005) plus filter Coquitlam • • • • 20 - 30 rechlori-nation stations

OptionS: Seymour Phase I and New Dam

Rechlorinate (2005) Phase II • • 0 .. Coquitlam 30 - 50 rechlori-(2031) nation stations

Option 6: Coquitlam Phase I Upgrade Dam

Rechlorinate (2005) • • 0 .. 45 - 60 rechlori-nation stations

• Best Meets Objectives • Meets Most Objectives () Partially Meets Objectives

Phase I - includes Westerly Transfer, primary disinfection with chlorine, secondary disinfection, and corrosion control. Phase II - includes Phase I plus filtration of Seymour Phase III - includes Phases I and II, plus filtration of CapUano

* Some costs common to all options are not included.

Flexibility *Cost in 1993$ (Millions)

for Phasing Average Net to Reduce Total Annual Present

Cost Capital O&M Value

• 674 20.1 1,054

• 302 11.2 619

0 1,251 35.5 1,642

0 1,150 37.4 1,729

() 716 22.6 1,114

4) 353 14.2 703

o Does Not Meet Objectives

I

'-

•

•

CJ ;3 \::1 \::1

~ ~.

~ ~ ... ~ ~ ~ ~ .... >:> E. V) {l 'l:5 ~

~ ~ ~ ~.

Various options reduce turbidity (cloudiness) by different amounts.


found. This is the reason why options 2, 4, and 6 which include an upgrade of Seymour Falls Dam are rated lower than the Options 1,3, and 5, where it is replaced by a new dam.

Differences in options are also apparent in terms of drinking water quality improvement and impacts related to secondary disinfection. Concerning water quality and the ability to consistently meet current Canadian Drinking Water Quality Guidelines, the options with the highest rankings are those which incorporate one or more filtration plants (Options 1, 3, 4, and 5). Filtration, followed by either rechlorination or chloramination, will produce the higher quality waters. Non-filtration options (2 and 6) do not address the turbidity problem in a direct manner at this time, but employ only the Westerly Transfer to provide source interchangeability. Turbidity is directly tied to GVRD's ability to properly disinfect the water. Any time turbidity exceeds 5 NTU, disinfection of the water for Giardia cannot be guaranteed.

Anticipated turbidity conditions (based on data from recent years) for the various options are as follows:

Alternative

Current Conditions Option 1 Option 2 Option 3 Option 4 Option 5 Option 6

Turbidity Exceeds 5 NTU Standard

15% (56 days/year) 1% (4 days/year) 5% (18 days/year) 0% (0 days/year) 0% (0 days/year) 1 % (4 days/year) 5% (18 days/year)

For Options 2 and 6 which do not employ filtration, the benefit of the Westerly Transfer begins to diminish rapidly beyond year 2015 because of increasing system demands. Concerning compliance with possible future standards, Options 5 and 6 are rated very low because it is anticipated that they will not be able to meet future THM or other disinfection by-product regulations.

Concerning disinfection, chloramination will produce a better water from health and aesthetic perspectives than rechlorination; however, chloramine will have a higher potential for adversely affecting sensitive, fish bearing streams. This is an unusual circumstance where public health and environmental concerns are at odds. Unfortunately, this presents a difficult choice for the GVRD Board. The Medical Health Officers support chloramination, and environmental government agencies support rechlorination. Thus, in the Environmental Criterion, Options 1 and 2 with chloramination are rated lower than Options 3 through 6 with rechlorination. Option 1, which incorporates a large filtration plant for the

14

Option

1

2

3

4

5

6


Exhibit 9 Water Quality Compliance vs. Costs (Uninflated $)

expanded Seymour source initially, should significantly improve water quality and potentially enable GVRD to operate with a slightly lower chloramine residual that would still be an effective disinfectant in the Seymour service area.

Percent Additional Cost Additional Cost Compliance Net per Year to per Year of Drinking Present Household Water for 100%

Water Value Bill** • Option as Compliance** Guidelines* (Millious) Presented (per Household)

95 - 98%+ $1,054 $100 $40

85% (Avg.) $619 $35 $70

100% $1,642 $170 $0

100% $1,729 $180 $0

90- 93%+ $1,114 $105 $115

75% (Avg.) $703 $45 $145

No Action 50% (Not Acceptable to B.c. Health Act)

Net present values are presented in Exhibit 9 along with levels of compliance with present and future drinking water quality standards. Net present value is an economic analysis tool used to combine future capital and annual operating and

* All options could achieve 100% compliance by filtering all sources. ** An approximation - Peak costs (1993$) which decrease after about the year

2005 (average rates for the first 20 years are about 40% less). Based on 10 year debt financing (for 20 year debt financing, water rates are less). Ex-cludes common cost improvements and does not include municipal charges.

+ The higher range of compliance reflects less reliance on Capitano because of increased Seymour filtered capacity with the new dam.

Question 1

maintenance costs for comparison purposes at a given point in time. In this case, costs have been forecasted to the year 2041. As indicated in Exhibit 9, the higher levels of compliance are normally associated with higher costs. It should be noted that all options can achieve 100% by filtering all sources. Option 1, which includes a filtration plant at Seymour and chloramination, has a high level of compliance and, relatively speaking, a moderate cost impact. Option 1 has the further benefit of fitting well into a phased approach to reduce initial costs yet allow for future improvements and also can readily meet future Canadian Drinking Water Quality Guidelines. Options 3 and 4, which include filtration of all sources and rechlorination, have the highest costs and achieve 100% compliance with drinking water regulations immediately. They do not provide flexibility for phasing as filtration plants are planned immediately.

Decisions That Need to be Made The decisions that need to be made revolve around answering the four questions originally proposed as follows.

Should the GVRD choose rechlorination or chloramination to provide a secondary disinfectant residual throughout the water system?

The trade-offs associated with this question are public health versus concern for fish. Unlike most cases where public health and environ-

15

Question 2

Question 3

Question 4


mental protection go hand-in-hand, this is one case where they oppose each other. The Medical Health Officers support chloramination and environmental agencies support rechlorination. Rechlorination and chloramination are the only viable choices - one must be selected to satisfy the B.C. Health Act. Public consultation is planned to better inform the public and to more clearly determine their preference.

What is the next source of supply - should GVRD expand supplies from Seymour or from Coquitlam?

Concerning the next source of supply, the two choices are Seymour and Coquitlam. Seymour requires a new dam which triggers filtration of the expanded source to control turbidity. Coquitlam has a greater quantity of water and requires negotiations with B.C. Hydro and eventually compensation for phasing out of the Buntzen power generating facilities as drinking water supply needs grow. Excluding filtration on Seymour, the costs to proceed with either Seymour or Coquitlam are about equal.

Does GVRD simply upgrade Seymour Falls Dam, or build a new, higher dam in conjunction with the expanded source?

The issue of whether to upgrade or build a new dam hinges on the selection of the next source. If Seymour is selected, then anew, higher dam that meets new earthquake standards would be built. If Coquitlam is selected, then the existing Seymour Falls Dam must be upgraded to meet those same standards. From a water supply reliability perspective, it would be better to have a new dam because a new water intake would be included to ensure operation during and more importantly following an earthquake.

How quickly should GVRO move toward filtration and which sources should be filtered first?

The trade-offs are costs for filtration versus better water quality and higher compliance with Canadian Drinking Water Quality Guidelines. Moderate levels of compliance with turbidity and primary disinfection standards can be met in the very near term without filtration using the Westerly Transfer, but compliance rapidly diminishes beyond year 2015 because of increasing water demands to the east. Filtration is the only answer to remove turbidity to gain and retain a high level of compliance. Seymour is the logical first source to be filtered, followed by Capilano. The nonfiltration options (2 and 6) have the flexibility to have filtration added now or in the future. The filtration plant for the Seymour source would be smaller and less costly for Options 2,4, and 6 than for Options 1,3, and 5 because the Seymour source is not expanded when the dam is upgraded.

16

-

For Position A, choose either Option lor 2.


Conclusions

A full range of treatment has been investigated, ranging from nonfiltration to filtration of all sources including use of ozone instead of chlorine, if desired, as a primary disinfectant in conjunction with filtration. Ozone treatment costs have not been included in the costs of the six options, but are outlined separately in Appendix A. Decisions need to be made now to commence the process. Options 5 and 6, which involve rechlorination without a commitment to filtration of all sources, are not expected to be viable long-term options. Those two options ignore the likelihood that THM levels will be lowered from the current, interim level of 100 ppb, and that maximum allowable levels for other disinfection byproducts such as haloacetic acids will be set in the future. Furthermore, if the levels of THMs are lowered and filtration of all sources is not employed, then chloramination would have to be installed system-wide to meet future guidelines and the GVRD would have 50 to 60 rechlorination stations throughout the region that would be abandoned. Thus, by eliminating Options 5 and 6 from further consideration, the choices are narrowed to Options 1, 2, 3, and 4, as shown on Exhibit 10 on page 19. Using the decision tree (Exhibit 10) as a guide, the issues are reduced to the following two positions. Position A - Chloramination, allows flexibility to choose which sources are to be filtered and when; whereas Position B - Rechlorination, makes a commitment to immediate filtration of all sources likely.

Position A - Chloraminate

Select chloramine as the secondary disinfectant, with more health benefits, lower costs, but potentially greater environmental impacts. Then the next decision involves choosing either Option 1 or 2:

Option 1: The moderate cost option that provides high drinking water quality and includes the following:

o Seymour as next new source of supply, o Seymour Falls Dam is replaced with a new larger structure designed to

meet earthquake standards along with a new water supply intake, o Filtration of an expanded Seymour source is immediate, and o Flexibility is retained for future improvements.

Option 2: The lowest cost option that provides moderate water quality improvements and includes the following:

o Coquitlam as next new source of supply, o Seymour Falls Dam is upgraded, but the supply is not expanded, o Filtration can be deferred, if desired, and o Flexibility is retained for future improvements.

17

For Position B, choose either Option 30r4.


Position B - Rechlorinate

Select rechlorination as secondary disinfectant with greater environmental benefits, but higher costs. Then the next decision involves choosing either Option 3 or 4:

Option 3: A high cost option which gains high water quality, and includes the following:

o

o o

Filtration of all sources immediately, including the expanded Seymour source, Seymour as primary new source, and Seymour Falls Dam is replaced with a new larger structure designed to meet earthquake standards along with a new water supply intake.

Option 4: The highest cost option which gains high water quality, and includes the following:

o Filtration of all sources immediately, o Coquitlam as next new source, and o Seymour Falls Dam is upgraded, but the supply is not expanded.

18

-


Exhibit 10. Water Treatment Decision Tree

Position A* aminate Select Chlor

(Optio n 1 or 2) Secondary Disinfectant

" Phase 1

Upgrade Chlorine Primary Disinfection, Corrosion

Control and Chloraminate at 3 Sources

"

'Phase 2

Filter Seymour and

I Continue Chloraminating

I

Phase 3

Filter Capilano and

Continue Chloraminating

(1994 Decision)

1994 Decision Minimum Works

Required

Additional D\VQIP

\Vorks Now or in the Future

...

Position B** Rechlori

(Option 3 nate or 4)

,r Phase 1 - Upgrade

Chlorine Primary Disinfection and Corrosion Control

Phase 2 - Filter Seymour Phase 3 - Filter Capilano

Additional - Filter Coquitlam

Construct 20 - 30 Rechlorination Stations

-------,,---------------,,-----()/Z:>P(' to I~,,~plaCt-:

C~ll1.('rine ~tS Prirn~.lr)'

·t~lnt anci

* Filtration phases can be delayed, if desired. ** Immediate filtration of all sources likely required.

19

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

L,

Appendix A - Drinking Water Quality Improvement Plan

Appendix A Drinking Water Quality Improvement Plan Table of Contents

Section 1.0 - Report Purpose ....... ............................................... A-1

Section 2.0 - Background ........ .................................................... A-2

Section 3.0 - Drinking Water Quality Issues ................................ A-3

Section 4.0 - The Drinking Water Quality Improvement Plan ...... A-7

Section 5.0 - Predesign and Planning Studies .......................... A-13

Section 6.0 - Environmental Impact Assessment of Secondary Disinfection .... .......................................................... A-19

Section 7.0 - Public Consultation .............................................. A-32

Section 8.0 - Conclusions .......... ... '" .......................................... A-33

Glossary .................................................................................... A-36

Attachment I - DWQIP/EIA Public Consultation ........................ A-39

Attachment II - Disinfection Practices in Selected Cities and Countries .................................................................. A-46

Attachment III - Letters from Metropolitan Board of Health of Greater Vancouver and the Department of Fisheries and Oceans ........................................................... A-47


Appendix A Drinking Water Quality Improvement Plan List of Exhibits

Exhibit A-1 Summary of Annual On-Line Average Turbidity Data ......................................................... A-5

Exhibit A-2 Disinfection By-Product Testing Results .............. A-16

Exhibit A-3 Benefits, Risks and Costs of Implementing the Phases of the DWQIP .................................... A-18

Exhibit A-4 Drinking Water Treatment Costs .......................... A-27

Exhibit A-5 Comparison of Rechlorination and Chloramination ..................................................... A-31

Exhibit A-6 GVRD Water Quality Inquiry Phone Line -Summary 1991 - 1992 ......................................... A-39

Exhibit A-7 Summary of Information Requests and Comments Made Throughout the Regional Drinking Water Consultation Program to September 1993 .................................................. A-40

Exhibit A-8 Summary of Information Distributed .................... A-41

Exhibit A-9 Workshops and Presentations ............................. A-44

Purpose is to summarize the recent develop-ments o/the DWQIP.


Section 1.0 Report Purpose

The Drinking Water Quality Improvement Plan (DWQIP) was adopted in principle by the GVWD Administration Board in 1990. Since that time the Predesign and Planning Studies, which were the first step in implementing the DWQIP, have been completed. In addition, the Environmental Impact Assessment (EIA) of Secondary Disinfection was carried out. As part of the DWQIP and EIA the GVRD has carried out a number of initial public consultation activities with further programs planned in early 1994.

The purpose of this report is, firstly, to bring together and summarize the historical aspects, the various technical issues, and reports and public consultation initiatives since 1990 that now make up the DWQIP. Secondly, the report provides summary conclusions on the various implementation options for the DWQIP.

The two primary initiatives summarized herein are as follows:

o Predesign and Planning Studies (9 reports) o Three Stage Environmental Impact Assessment (EIA) of

Secondary Disinfection (3 reports)

A-J

The DWQIP was developed in response to health concerns related to the region's drink-ing water.

GVRDBoard Policy is to im-plement the DWQIP.

Section 2.0 Background


2.1 Historical Perspective The Greater Vancouver Water District (GVWD) was formed in 1926 and became part of the Greater Vancouver Regional District (GVRD) in 1971. The GVWD is a wholesale drinking water supplier, providing water to 18 municipal entities. The surface water is unfiltered with only coarse screening and chlorination currently used at the source lakes. Chlorine has been used to disinfect Greater Vancouver water since the early 1940s, when the federal government insisted the GVWD chlorinate water to protect the supply of water on ships bound for war.

Water quality concerns identified in the early 1980s led to a report to the Board in June 1986 which provided preliminary information on the system's water quality as well as individual municipal operating practices. It identified improvements that were needed in both of these areas to improve water quality and recommended increased levels of chlorination of the water supply and further testing and investigative work. The approach was confirmed in a subsequent consultant report. In January 1988, the GVRD embarked on a comprehensive study to improve the drinking water quality supplied to its member municipalities. The Drinking Water Quality Improvement Study, undertaken by consultants, included literature reviews, laboratory analyses, extensive pilot treatment testing and a fullscale demonstration secondary disinfection water treatment project in Surrey. The purpose of the study was to develop the most satisfactory improvements which would enable the GVWD and member municipalities to meet provincial and federal drinking water quality standards. The Study culminated in 1990 with the Drinking Water Quality Improvement Plan approved, in principle, by the Administration Board.

2.2 GVRD Board Policy on Drinking Water Quality

In 1990, the GVRD Board adopted Creating Our Future, which established an action plan for all regional activities. Creating Our Future was updated in 1992 to reflect current GVRD Board Policy and adopted on February 26, 1993 as Creating Our Future 1993. Maintaining a Healthy Environment, one of the five main themes, includes specific objectives and actions related to drinking water. The specific policy related to the Drinking Water Quality Improvement Plan (DWQIP) includes adoption of the Plan by the Board in 1990 and in Creating Our Future 1993 - Drinking Water Quality, the GVRD Strategic Policy is to Continue to develop and implement the Drinking Water Quality Improvement Program.

A-2

-

Greater Van-couver is the only major cen-tre in Canada that does not comply with all Canadian Drinking Water Quality Guidelines.

B.C. Safe Drinking Water Regulation sets legal require-ments.


Section 3.0 Drinking Water Quality Issues

3.1 Drinking Water Quality Standards

The Guidelines for Canadian Drinking Water Quality are published by Health Canada, and are used by water utilities in Canada as the standard to meet. Greater Vancouver is the only major centre in Canada that does not comply with all the Guidelines. The DWQIP developed for the GVWD and its members follows sound drinking water treatment and supply practices by establishing a course of action that will enable compliance with these Guidelines.

In British Columbia, the operation of most waterworks systems falls under the jurisdiction of the Ministry of Health through the Health Act. The B.c. Ministry of Health uses the Guidelines for Canadian Drinking Water Quality to judge the quality of water provided by the various waterworks systems. In October 1992, the Ministry of Health established the Safe Drinking Water Regulation which essentially makes the Canadian Guidelines for fecal and coliform bacteria an enforceable standard in British Columbia. There is, therefore, a legal requirement for the GVWD and its members to meet the Safe Drinking Water Regulation with potential legal liabilities for noncompliance. Contravention of this regulation, or an order made pursuant to it, is an offense and subject to a fine of up to $2,000 or to imprisonment for up to six months, or both. The Regulation empowers the Medical Health Officer (MHO) to require improvements to bring the water into compliance with the microbiological standards for potable water.

3.2 Overview of Drinking Water Quality Issues

For the GVRD, meeting drinking water standards requires solutions to four main concerns:

o Vulnerability to an outbreak of giardiasis (waterborne disease) from the source waters.

o Bacterial regrowth resulting in unacceptable total coliform counts in the water distribution system.

A-3

Four Water Quality Issues:

• Giardiasis • Bacterial

Regrowth • High

Turbidity • Corrosion

Some source water samples contain Giardia cysts. The pre-sent treatment system is not capable of killing or removing cysts.

Bacteria levels in tap water are un-acceptably high.


o Unacceptable periods of high turbidity (cloudiness) exceeding 5 Nephelometric Turbidity Units (NTU) thereby compromising primary disinfection.

o Corrosive nature of the water resulting in health, economic, and aesthetic concerns.

Each of these concerns is briefly discussed in the following sections.

3.2.1 Giardiasis Vulnerability

The present chlorination system at the sources (primary disinfection) is not adequate to ensure inactivation of Giardia cysts in water supplied throughout the region because there is an inadequate concentration of chlorine and insufficient contact time. An outbreak of giardiasis (commonly referred to as beaver fever or rocky mountain fever). linked to the water supply has not occurred to date in the Greater Vancouver area. Giardia cysts, however, have been detected in the source waters. Monitoring by U.B.C.'s laboratory has found approximately 10% of the water samples collected at the source intakes positive for Giardia cysts. The Canadian Guidelines state "It is desirable ... that no virus or protozoa (e.g. Giardia) be detected." Furthermore, outbreaks of this waterborne disease have occurred without warning on other surface water supplies in British Columbia and Washington State in recent years necessitating the need for prompt remedial action.

3.2.2 Bacterial Regrowth in the Transmission and Distribution System

Water quality sampling for the GVWD member municipalities indicates that the ten percent maximum coliform standard in the B.c. Safe Drinking Water Regulation was exceeded on a regional average for each municipality for about two months of the year for 1991 and 1992. In the same two year period, five municipalities exceeded the coliform standard for five or more months per year, typically in the warmer summer months and early fall. Even one period (30 days) over the ten percent standard contravenes the B.c. Safe Drinking Water Regulation and the Canadian Drinking Water Quality Guidelines.

Another determination for the presence of elevated levels of bacteria is the heterotrophic plate count (HPC) measured as colony forming units (cfu) per millilitre (rnL). HPC bacteria can also interfere with the measurement of coliform and pathogenic bacteria (e.g., Salmonella) and therefore result in a false indication of potability. The Canadian Guidelines require HPCs to be less than 500 cfu/mL. Greater than 500 cfulrnL occurs throughout

A-4

Lack of chlorine residual allows bacteria to grow.

Periods of high turbidity may compromise disinfection of water and are unacceptable from an aesthetic perspective.

Capilano


the year for the GVWD reservoirs, the GVWD trunk mains, and all municipal distribution systems.

Increased levels of coliform growth and HPC bacteria in the warmer summer and fall months are a result of low or zero chlorine residuals in about eighty percent of the water samples. While not a significant health problem by itself, the presence· of bacterial growth also indicates that opportunistic pathogenic bacteria (e.g., Pseudomonas and Legionella) could thrive and develop into a serious health concern.

3.2.3 Turbidity

Excessive turbidity in the water is primarily a result of heavy winter rains causing erosion of flooded streams in the watersheds and natural slides on steeper, unstable areas. High turbidity, while undesirable from an aesthetic perspective, is a health concern as the presence of the suspended matter can impede the ability of a primary disinfectant, chlorine (or ozone), to provide adequate disinfection. Exhibit A-I presents on-line average turbidity data for each source from April 1989 to April 1993. Prior to 1989 only grab samples were available for turbidity analysis. The

>5NTU 55 days per year

(15%)

Coquitlam

Seymour


(1.1%)


(5.2%)

Canadian Guidelines state an average maximum acceptable concentration (MAC) of 1 NTU of turbidity, but will allow up to 5 NTU, provided it can be shown that disinfection is not compromised.

NTU - nephelometric turbidity units

As indicated in Exhibit A-I, Capilano water exceeded turbidity guidelines of greater than 5

Exhibit A-1. Summary of Annual On-Line Average Turbidity Data (April 1989 to April 1993)

NTU 15% of the time, Seymour 5% of the time, and Coquitlam 1% during the four year period.

During the most recent worst twelve month period for turbidity, November 1990 to October 1991, Capilano and Seymour sources exceeded 5 NTU approximately 38% and 18% of the time, respectively. From February

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The corrosive na-ture of the water is a significant con-cern to the region.


1990 to January 1991, Coquitlam exceeded 5 NTU 2% of the time. Greater Vancouver is the only major city in Canada that does not meet the 5 NTU turbidity limit set out in the Canadian Guidelines. The primary objective of the turbidity guideline is to ensure that disinfection and prevention of waterborne disease is not compromised.

3.2.4 Corrosion

The GVWD has very soft water because it is derived from rain water and snowmelt, and it's short contact time with the soil and low mineralization of geologic features in the watersheds significantly reduces the opportunity to acquire buffering minerals before entering the lakes. The low mineral content of the water results in an acidic water which corrodes plumbing systems and leaches lead and copper into water that has been standing for a period of time such as overnight. The result is that plumbing in the Region has a relatively short life, the leached lead is a health concern, and the corroded copper causes plumbing fixture (blue-green staining) and laundry staining which are aesthetic concerns. The cost of the corrosion to the community was estimated in the 1990 study to be about $10 million per year in terms of plumbing maintenance and replacement costs. There are also reports of individual high-rise building plumbing replacement costs of over $0.5 million in as little as 12 years after construction.

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-

DWQIP approv-ed in principle in 1990.

Phase 1 includes supplying clearer Coquitlam water to the west side of the region during high turbidity.


Section 4.0 The Drinking Water Quality Improvement Plan (DWQIP)

4.1 DWQIP - Overview

The DWQIP adopted in 1990 proposes a three phased solution to the water quality issues discussed above. Phase 1 includes upgraded primary disinfection, introduction of secondary disinfection and corrosion control facilities at all three water sources, and construction of facilities to transfer less turbid Coquitlam water in a westerly direction. Upgraded disinfection will include new facilities to increase chlorine levels during primary disinfection and increasing contact times needed to inactivate Giardia cysts. Introduction of secondary disinfection will also require new facilities to ensure a disinfectant residual is maintained throughout the distribution system. Corrosion control will involve increasing the existing water pH of 6 to about pH 8 and increasing alkalinity from less than 5 mg/L to between 20 and 30 mg/L through the addition of dissolved carbonate minerals, as well as the possible addition of corrosion inhibitors.

Phases 2 and 3 of the DWQIP include filtration plants at Seymour and Capilano, respectively, to address the turbidity and primary disinfection concerns. The DWQIP recommended Predesign and Planning Studies be carried out for Phase 1 and Phases 2 and 3, respectively, to further define the costs and requirements of implementing the plan. Since the adoption of the DWQIP in 1990, a significant program adjustment has been made that may alter the overall character of the DWQIP. This was the initiation of an Environmental Impact Assessment (EIA) of Secondary Disinfection which required a review of this aspect of the DWQIP.

4.2 DWQIP - Phase 1

4.2.1 The Westerly Transfer

The upgrading of the distribution system network to permit source interchangeability between Coquitlam and the Seymour and Capilano service areas will improve system reliability and emergency water supply capabilities. In addition, this could allow the GVRD to remove either the Capilano or Seymour source, but not both, from service when turbidity events occur at these sources during lower winter time flows. The demand would be met with additional water pumped from the Coquitlam source. The facilities being built to provide this capability are collectively termed

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The effectiveness of the westerly transfer is limited due to population growth in the eastern parts of the region.

Phase 1 also in-cludes upgrading primary disinfec-tion, corrosion control, and secondary disin-fection using rechlorination (higher chlorine levels) or chlora-mination.


the Westerly Transfer. Based on future demand forecasting in the eastern area of the GVRD and current source supply capacity, the westerly transfer of water from the Coquitlam service area may not be possible, depending on actual demands during winter months, beyond about the year 2015. Increased source supply and transmission capacity are expected to be required by this time. The details associated with this issue are being investigated under the Comprehensive Regional Water Supply Study (CRWSS).

The beneficial limits of the Westerly Transfer are apparent, in terms of water quality improvement, when the last four years of turbidity data are evaluated. During this period, Greater Vancouver experienced a number of extreme rainfall events. Turbidity levels at both Capilano and Seymour sources exceeded 5 NTU at the same time for 74 days. On two occasions measurements above 30 NTU occurred simultaneously at two sources. Under these conditions only one source could be removed from service.

The Westerly Transfer also would probably not be effective for the unusual circumstances of turbidity events in the summer, such as occurred in August 1991, and during the summers of 1972 and 1973. The Westerly Transfer cannot meet flow demands to fully replace even one source during the higher water demand of the summer months.

The Westerly Transfer will, however, help to reduce the frequency of excess turbidity introduced to the system. Based on continuous on-line data collected from April 1989 to April 1993, the excess turbidity occurrence in the total system could have been reduced from 15.3% of the time, an average of 56 days per year, down to 5.0% of the time, or 18 days per year. The worst twelve month period from the recent on-line data occurred between November 1990 and October 1991. During this period the Westerly Transfer could have reduced turbidity events greater than 5 NTU from 37.5% to 18.1 % of the time (137 days to 66 days).

4.2.2 Enhanced Treatment Without Filtration

This part of Phase 1 includes upgrading of primary disinfection facilities for Giardia cyst inactivation (considered reliable only when turbidity is less than 5 NTU), pH and alkalinity adjustment for corrosion control, and secondary disinfection using distribution system rechlorination (higher chlorine levels) or chlorarnination at the source. The B.c. Safe Drinking Water Regulation, which only addresses coliform bacteria, is expected to be satisfied with these measures. There will be significant improvement towards complying with the Canadian Guidelines with construction of Phase 1, however, some health risks would still be present. This includes continued risk of giardiasis with high turbidity (above 5 NTU). Of lesser concern (primarily aesthetic) would be continued episodes of coloured

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GVRD needs to improve main-tenance, opera-tionaland construction practices.

More flushing and cleaning of watermains would help prevent water quality deteriora-tion.

Currently $0.8 million is spent per year on flushing and cleaning.


water associated with high iron. Corrosion of copper piping is expected to be reduced by between 50 and 60 percent following completion of Phase 1. If rechlorination is used as a secondary disinfectant without filtration, levels of disinfection by-products will probably exceed the proposed Canadian Guidelines. In the range of 50 to 60 rechlorination stations will be required in the Region if rechlorination (higher chlorine levels) is selected as the method of secondary disinfection.

4.2.3 DWQIP - Operations Program

In addition to the construction of upgraded treatment facilities, the DWQIP, in conjunction with Phase 1, includes a program to improve system operating procedures. Both GVWD and municipal systems need to improve their operations and maintenance procedures as they relate to protection of water quality.

For GVWD and some municipalities, a primary problem relates to the lack of circulation in balancing reservoirs in the transmission system, which contributes to the loss of chlorine residual and the growth of bacteria. GVWD may need to modify the existing reservoir structures and the method of operation to encourage water circulation and deter loss of chlorine residual and resulting bacterial growth. This should be assessed further after secondary disinfection has been implemented.

Municipal systems need to initiate or continue procedures to design, construct and operate their facilities to prevent water quality deterioration. For example, areas with pipelines that have poor circulation need to be looped to improve circulation, and water main flushing and/or cleaning programs need to be initiated or continued. Repairs and new water main construction need to be performed using recognized sanitary procedures. Standards and operating procedures of the American Water Works Association, a long established North American water works association, need to be adopted and adhered to, where not already done so.

The GVRD has continued to monitor municipal operations practices through questionnaires in 1988 and 1992. The findings indicate that all municipalities practice flushing of water mains to improve water quality. Mechanically cleaning ("pigging") of water mains has been used by up to eight municipalities but is presently used to varying degrees by only seven municipalities. Pigging may help to reduce the concentration of the secondary disinfectant required in some municipalities, but it does not eliminate its need. Municipalities have improved their design, construction and operational practices since the mid-1980s to improve water qUality. There is currently $0.8 million spent annually on flushing and cleaning water mains in the region, however, some of the programs are limited and further improvements can be made.

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Phase 2 is filtration of the Seymour source to improve water quality and to ensure compli-ance of this source with standards.

Phase 3 is filtra-tion ofCapilano to improve water quality and en-sure compliance of this source with standards.


4.3 DWQIP - Phase 2, Filtration of Seymour Source

There were 76 days (5% of the time) exceeding 5 NTU between April 1989 and April 1993 in the Seymour service area. Filtration of the Seymour source would result in consistently high quality water of about 0.1 NTU, removing any Giardia cysts that may be present and ensuring primary disinfection is not compromised. The combination of the Westerly Transfer with a filtered Seymour source would significantly reduce the risk of exceeding 5 NTU if Capilano could be removed from service during periods of high turbidity, and replaced with increased flows from Seymour and Coquitlam. The combination of filtering Seymour and constructing the Westerly Transfer would see a reduction in risk of supplying water exceeding 5 NTU from 15% down to 1% of the time, based on recent historical records and short term flow demand projections. The remaining risk would be that associated with Coquitlam's inability to provide low turbidity water, which averaged 4 days per year (about 1 % of the time) greater than 5 NTU between April 1989 and April 1993.

The coloured water problem, a result of high iron, is usually experienced only at Seymour. Filtration at this source would eliminate this problem.

Possible future dam upgrades to raise the water level at Seymour for water supply would be expected to cause significant short term deterioration of water quality from this source due to the expected failures of saturated slopes around the lake until the reservoir restabilizes. Based on the records of turbidity in Capilano and Seymour Lakes after construction of Cleveland and Seymour Falls Dams in the 1950s and 1960s, frequent high turbidity episodes might last from 5 to 10 years. Turbidity previously acceptable in the 1950s and 1960s is not acceptable by either the current health standards or the public. Construction of a filtration plant prior to or in conjunction with future dam construction would ensure the quality of the water from this source is protected.

4.4 DWQIP - Phase 3, Filtration of Capilano Source

There were 219 days (15% of the time) exceeding 5 NTU between April 1989 and April 1993 in the Capilano service area. Filtration of Capilano would result in consistently high quality water from this source of about 0.1 NTU, removing any Giardia cysts that may be present and ensuring that primary disinfection is not compromised. With all three phases of the Drinking Water Quality Improvement Plan completed, the only risk of high turbidity water would be the Coquitlam source which had 16 days

A-IO

The 1990 DWQIP does not include filtration of the Coquitlam source.


(1 % of the time) greater than 5 NTU between April 1989 and April 1993, or about four days per year. With Phases 1, 2 and 3 of the DWQIP completed it would be possible, by reversing the westerly transfer of water, to remove high turbidity Coquitlam source water from service depending on the flow demands, at least in the initial years. Upgrading and expansion of the Seymour source supply capacity would help facilitate this option as is being considered in the Comprehensive Regional Water Supply Study (CRWSS) now in progress.

4.5 Coquitlam Source Issues

The DWQIP does not include filtration of Coquitlam because of the historically low incidence of turbidity. As a result of higher than normal precipitation, there has been a slight increase in turbidity events exceeding 5 NTU amounting to eight events in the last four years or about 1 % of the time. The longest duration was four days.

Some of these high turbidity incidences coincided with the recent draw down of the reservoir by B.C. Hydro for repairs at the dam site. Rain eroded the silt on the exposed lake shore at the south end of the lake, generating turbid water in the area of the GVWD intake. Increased water use for domestic purposes, lower lake levels for downstream flood control, and maintenance requirements could produce similar lake levels in the future, resulting in the potential for more frequent turbidity events greater than 5 NTU.

In terms of solving the occasional high turbidity events, consideration should be given to the application of remediation measures such as geotextile fabric and rip-rap along the easily eroded surfaces at the south end of the lake before proceeding to costly filtration of the Coquitlam source.

If rechlorination is selected as the secondary disinfectant, disinfection byproducts such as trihalomethanes will exceed possible future Canadian Guidelines unless this source is filtered.

4.6 Balancing Risks, Benefits and Costs

The objective of the phased DWQIP adopted in 1990 was to maximize the public health benefits of improving drinking water quality while minimizing costs. The environmental impact risks associated with secondary disinfection utilizing chloramination were not anticipated as no other water systems had encountered similar impacts. The challenge that now lies ahead when considering disinfection and treatment of the region's water is

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Microbiological and disinfection by-product con-cerns and en-vironmental risks must be balanced at a cost accept-able to the public.


the issue of balancing microbiological and disinfection by-product health concerns and environmental risks, all at a reasonable cost.

In order to resolve the serious microbiological health risks related to bacterial regrowth as identified in the DWQIP our drinking water must be adequately disinfected. Disinfection technologies, however, such as chlorination, chloramination, and ozone can all produce disinfection byproducts (DBPs) in varying amounts, depending on the disinfectant, that are identified as low risk carcinogens. These DBPs are produced by the disinfectant altering or reacting with compounds found naturally in the water. Even though the risks are very low and the substantial benefits of disinfection are universally recognized, the public concern and increasing scrutiny of the health risk of these compounds indicate that DBPs as a water quality issue must be addressed.

There are readily available technologies to minimize the risks and increase benefits, however, there are increasing costs associated with this path.

Pilot plant studies conducted as part of the Predesign and Planning Studies discussed in Section 5.0 investigated the resultant levels of DBPs under proposed and alternative treatment technologies. Section 5.0 also summarizes the benefits, risks and costs of phasing the DWQIP. The Environmental Impact (EIA) of Secondary Disinfection summarized in Section 6.0 raises and discusses the issues of microbiological and DBP health concerns and environmental risks and provides costs for various treatment options.

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Predesign for Phase 1 has been completed.

Filtration plant planning includ-ing possible future use of ozone has been completed.


Section 5.0 Predesign and Planning Studies

5.1 Overview

The Predesign and Planning Studies, as recommended in the 1990 nWQIP, were the first step towards implementation of the plan. The GVRn Board at the June 26, 1991, meeting awarded the Predesign and Planning Studies, which included filtration pilot plant studies for the proposed drinking water quality improvement facilities to the consultant consortium of Stanley, Crippen, Black and Veatch (SCBV) Consultants Inc.

The Predesign and Planning Studies undertaken by SCBV Consultants Inc., were defined in three parts and included the following:

o Predesign of disinfection and corrosion control facilities at Capilano, Seymour and Coquitlam Sources (nwQIP Phase 1).

o A pilot filtration plant study conducted to establish unit process criteria and general design concepts needed for planning filtration plants at Capilano and Seymour Sources (nWQIP Phases 2 and 3). This included evaluation of ozone as a primary disinfectant and extensive disinfection by-product testing.

o A planning study performed to develop the conceptual design and preliminary siting for the Seymour and Capilano water filtration plant(s) in order to accurately estimate the filtration plant costs (nwQIP Phases 2 and 3).

The studies resulted in the production of eight reports and a Summary Report. The Summary Report, dated June 1993, was forwarded to the GVRD Water Committee on July 15, 1993. In addition, the Summary Report was circulated to the Regional Engineers Advisory Committee (REAC) , municipal Water Quality Technical Committee (WQTC), Regional Medical Health Officers, and representatives of the B.C. Ministry of Health and Health Canada for their review. Environment Canada, Fisheries and Oceans, B.C. Environment, the Regional Water Advisory Committee (RW AC), interested non-government organizations and interested public have also received copies of the report.

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Final site selec-tion will be subject to public consultation.

New disinfection and corrosion control facilities and construction ofa4km long tunnel are required at Capilano.

A new disinfec-tionfacility is required at Seymour Dam and a corrosion control facility is required at Rice lAke.


5.2 Site Selection

Sites for the water treatment plants discussed in the following sections were determined through a screening process of economic, social, environmental and engineering feasibility constraints as part of the Predesign and Planning Studies. Final selection of sites, however, are still subject to public consultation.

5.3 Predesign of Disinfection and Corrosion Control (DWQIP Phase 1)

The DWQIP Phase 1 calls for disinfection and corrosion control facilities to be constructed at the three sources as discussed below.

5.3.1 Capilano

A disinfection and corrosion control facility to meet a peak hour flow of 1140 ML/day (present capacity unchanged to year 2041) can be constructed at a new building near the base of Cleveland Dam at the site of the present chlorination station. Geographic and economic factors support the construction of a 4 kIn long, 4 metre diameter lined U-tunnel to serve as chlorine contact which would be constructed eastward for eventual extension (DWQIP Phase 3) to the water treatment plant site near Rice Lake in the Seymour Demonstration Forest. The primary disinfectant proposed is chlorine (the potential use of ozone as a primary disinfectant is discussed in Section 6.2 Drinking Water Treatment Alternatives), which would be added to the Capilano water at the tunnel entrance with the required cont~ct time being achieved in the tunnel. At the tunnel exit and prior to entering the distribution system, the pH and alkalinity of the water would be adjusted and the secondary disinfectant created by adjusting the level of free chlorine andlor adding ammonia to create chloramine depending on which is chosen as the secondary disinfectant.

5.3.2 Seymour

Primary disinfection would occur at a new facility constructed at Seymour Falls Dam, the existing 11 kIn pipeline would be used to achieve the required contact time, and corrosion control and secondary disinfection would occur at a site near Rice Lake. The facilities would be designed for a peak hour flow of 980 ML/day (present capacity unchanged to year 2041).

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New disinfection facility is requir-ed at Coquitlam Dam.

New corrosion control facility is required south of dam site near gravel pits.

Filtration pilot study reveals major savings can be achieved by using direct filtration.

Ozone was in-vestigated and could be used as primary disinfectant.

Filtration im-proves water qua-lity and lowers disinfection by-products.


5.3.3 Coquitlam

Primary disinfection would occur at a new facility constructed at the Coquitlam Dam. The existing 5.5 kIn pipeline would be used to achieve the required contact time for initial flows, and corrosion control and secondary disinfection facilities would be constructed downstream near the gravel pits on the dam access road. As the demands on the Coquitlam source increase the pipeline will have to be upgraded. The upgraded pipelines would satisfy the contact time for the increased flows. Initial disinfection and corrosion control facilities would be sized for a peak hour flow of 2390 ML/day (to the year 2017) and will eventually require expansion to 2840 ML/day (year 2041). Current peak hour flows are around 600 ML/day.

The estimated total cost of the Phase 1 disinfection and corrosion facilities, including the water quality share of the westerly transfer piping systems, is $130 million (1993 dollars) for chloramination, including mitigation costs, and $170 million (1993 dollars) for rechlorination.

5.4 Pilot Filtration Plant Study

The pilot filtration plant study program was conducted over a one year period (all water quality seasons) on both the Capilano and Seymour sources. The purpose of the program was to establish unit processes and conceptual design criteria for filtration plants for both sources. A number of different process options, including ozonation, were considered. Water quality and filtration performance goals were defined in cooperation with GVRD staff, the consultant and a Technical Review Board, to enable the evaluation of pilot plant test results. The Technical Review Board was a group of water treatment experts from North America and Europe who were retained to provide insight on issues critical to the future of water quality and treatment in Greater Vancouver.

The primary conclusion from the program is that direct filtration (without the use of settling tanks) using high flow rate filters with free chlorine or chloramine as a secondary disinfectant will meet the current and foreseeable Canadian Drinking Water Quality Guidelines. This substantially reduces the cost of filtration compared to conventional methods of treatment.

Pilot filtration plant testing summarized in Exhibit A-2 on the next page indicated that chloramine secondary disinfection produced lower levels of disinfection by-products than chlorine secondary disinfection and filtration reduced disinfection by-products formed by both secondary disinfectants. Ozonation with filtration and chloramination produced the lowest levels of disinfection by-products of all treatment scenarios. Health Canada has

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48-hour concentration. ugIL

100

80

60

40

20

o UnfIltered, ChlorineChlorine

Seymour Pilot Plant Effect of Treatment on 48-hour Daps Phase 3 28, 1992


_ Trihalometbane (Chloroform) ugIL

Unfiltered, Chlorine

Chloramine

Filtered, ChlorineChlorine

Filtered. Chlorine

Chloramine

Filtered, Ozone

Chlorine

(DCAAand

Filtered, Ozone-

Chloramine

Source: SCBV Consultants, Inc., Predesign and Planning Studies - Summary Report (June 1993)

lowered the Canadian Drinking Water Quality Guideline for trihalomethanes (THM) maximum acceptable concentration (MAC) from 350 JlglL for anyone sample to an interim MAC (IMAC) of 100 JlglL based on average quarterly Exhibit A-2. Disinfection By-Products Testing Results

A combined Sey-mourlCapilano filtration plant can be construct-ed at Rice lake.

A tunnel will connect Capilano and Seymour sources.

samples. A MAC of 50 J..1glL, as originally proposed, may be set at the end of the interim period. The impact of this is discussed in Section 6.3.2.

5.5 Filtration Planning Study for Seymour and Capilano (DWQIP Phases 2 and 3)

A number of potential sites were identified for locating water filtration treatment plants for the Capilano and Seymour sources (a site for possible future Coquitlam filtration was also identified for long range planning purposes). Final selection of site(s) will involve a public consultation program. The option that is the most economical for filtration of Capilano and Seymour sources, considering both construction and operating costs, is to use the GVWD owned site near Rice Lake for construction of a combined filtration plant to treat both sources. Phase 2 of the DWQIP would see a filtration plant with a capacity of 950 ML/day constructed to treat Seymour water initially. Phase 3 of the DWQIP would see the plant expanded to a total capacity of 1900 ML/day, the Capilano Disinfection and Corrosion Control facility converted to a pumping station and the Phase 1 V-tunnel extended to the Rice Lake site. Raw water from Capilano would then be pumped through one tunnel to the combined treatment plant and the treated water returned to the Capilano distribution system through the second tunnel. On-site underground geotechnical investigations are required to refine the tunnel concept.

Sufficient area is available at the Rice Lake site for further expansion of the treatment plant should the Seymour source capacity be expanded by raising Seymour Falls Dam. In addition, all predesign and planning has allowed for future addition of ozone and/or conversion to biological filtration, if required in the future.

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DWQIPcanbe implemented in phases or all three phases can be implemented immediately.


5.6 DWQIP - Implementation

In order to completely solve the four water quality concerns facing our region and to ensure that our drinking water meets the B.C. Safe Drinking Water Regulation and the Guidelines for Canadian Drinking Water Quality, full implementation of the DWQIP is required. If rechlorination is selected as the secondary disinfectant, filtration of Coquitlam, which is not included in the original DWQIP, would also likely be required to comply with future possible guidelines for disinfection by-products.

The benefits, risks and costs of delaying phases versus initial implementation of all phases of the program are summarized on Exhibit A-3. The degree of implementation (timing of the construction of each phase) of the plan will be the focus of the next stage of public consultation.

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ExhibitA-3 Benefits, Risks and Costs of Implementing the Phases of the DWQIP

Capital Cost (1993 $ million)

Benefits Risks Rechlorination Chloramination

Option A - Implement Phase 1 (Disinfection and Corrosion Control AU Sources)

Cl Phase I expected to satisfy B.C. Safe Cl Continued risk of giardiasis at high $150 $100

Drinking Water Regulation and turbidity. substantial increase in Canadian Cl Episodes of coloured water and high Drinking Water Quality Guidelines iron will continue with Phase 1. compliance.

Cl Cannot handle turbidity at both Cl Resolve bacterial regrowth and Capilano and Seymour at same time

corrosion control for all sources. with Westerly Transfer. Cl Resolve giardiasis risk at low Cl If rechlorination used, high DBPs

turbidity (below 5 NTU). (disinfection by-products) at Capilano, Coquitlam and Seymour until filtration built.

Cl If chloramination used, additional $101

costs proposed for mitigation. Cl Westerly Transfer (Water Quality

Improvement share) currently underway to reduce turbidity $20 $20

Total Option A $170 $130

Option B - Implement Phases 1 and 2 (Disinfection and Corrosion Control All Sources and Seymour Filtration) Cl Turbidity, giardiasis risk, iron and Cl Some continued risk of giardiasis and

colour in Seymour service area turbidity at Capilano when service eliminated, and with Westerly area demand too high to be handled Transfer risk is greatly reduced in by Seymour and Western Transfer. Capilano service area. Cl If rechlorination used as secondary

Cl If rechlorination used, reduce number disinfectant, high DBPs continue at $152 $152

of rechlorination stations in Seymour Capilano and Coquitlam without service area. filtration.

Cl Allow evaluation of effect of filtration on bacterial regrowth.

Cl If rechlorination used, reduce DBPs in Seymour service area.

Total Option B $322 $282

Option C - Implement Phases 1, 2, and 3 (Disinfection and Corrosion Control All Sources and Seymour and Capilano Filtration) Cl Turbidity, giardiasis, iron and colour Cl If rechlorination used, high DBPs $193 $193

eliminated in Capilano and Seymour. continue from Coquitlam source.

Cl Meets virtually all Canadian Cl Low risk of giardiasis when Guidelines (rare high turbidity Coquitlam source has high turbidity. continues at Coquitlam).

Cl If rechlorination used, meets proposed guidelines for DBP in Capilano and Seymour services areas.

Cl Less municipal water main flushing in Capilano and Seymour service areas.

Total Option C $515 $475

(I) This is a preliminary estimate for mitigation if chloramination is used.

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-

The Environ-mental Impact Assessment (EIA) was a three stage process.

Consensus was reached on the technical content of the Stage III Report.


Section 6.0 Environmental Impact Assessment of Secondary Disinfection

6.1 EIA Process

The 1990 DWQIP originally proposed chloramination as a secondary disinfectant to solve the bacterial regrowth problem discussed in Section 2.2. As a result of two fish kills in the chloramination demonstration area in South Surrey and a subsequent Section 37 Fisheries Act request, the GVRD undertook an environmental impact assessment (EIA) of secondary disinfection.

The three stage EIA process included a review of the DWQIP and alternative treatment technologies and compared the health, environmental, aesthetic and economic impacts of the two viable secondary disinfection options, rechlorination and chloramination. The environmental assessment was not able to predict numerical resource impact values, however, it was able to produce a comparative basis for the two alternative secondary disinfectants. The assessment of impacts of secondary disinfection alternatives and associated reporting was undertaken in three stages to enable input from the public and government agencies to be incorporated.

Three reports were prepared by Norecol Environmental Consultants Ltd., as follows:

o Stage I - Baseline Study, December 1992 o Stage II - Environmental Impact Assessment, May 1993 o Stage III - Summary Report, November 1993

Interested individuals and groups provided input to the process through a variety of communication mediums (e.g., surveys, newsletter, written submissions, and phone line). The Regional Water Advisory Committee (RW AC) is a citizens advisory group established to review a number of GVRD water programs including the DWQIP and EIA. The Department of Fisheries and Oceans (DFO), Environment Canada (EC), and Ministry of Environment, Lands and Parks (MOE), have reviewed and commented on the scope of work and the preliminary data collection as well as the content of the three EIA reports. As well, consensus with environmental agencies was reached on the technical content of the Stage III Report.

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Various alternative treatment techno-logies were investigated.

Filtration will reduce the number of rechlorination stations.


The key technical issues associated with the EIA were summarized in the Stage III EIA by Norecol Environmental Consultants Ltd., under the following categories: treatment alternatives, health, environment, water users, and cost. Each of these issues is discussed below followed by a summary of public opinion and conclusions of the EIA.

6.2 Drinking Water Treatment Alternatives

During the EIA process, questions were raised by the general public and government agencies regarding the choice of methods for secondary disinfection. They suggested that disinfection technologies other than rechlorination or chloramination should be considered further. Some of the technologies that were suggested included ultraviolet radiation and ozone. A number of people also believed that filtration of the water supply would negate the need for secondary disinfection. It was, however, concluded from consultant studies that secondary disinfection of the water supply is required for the GVWD to consistently meet the microbial standards legislated in the British Columbia Safe Drinking Water Regulation, even with filtration and ozonation. As well, a secondary disinfectant is normally used to provide protection against opportunistic pathogens that may develop into a serious health problem or contamination from pathogenic microorganisms that may enter the water distribution system as a result of accidents such as water main breaks or back siphonage.

Available disinfection technologies were reviewed during the development of the DWQIP, and this information was revisited and summarized in the EfA Baseline (Stage 1) Report. The following treatment technologies were considered: chlorine, chloramine, chlorine dioxide, ultraviolet light, potassium permanganate, filtration, ozone, and biological filtration. Chlorine, chloramine, and chlorine dioxide are used throughout the world as secondary (distribution system) disinfectants. Chlorine dioxide was initially considered by the GVRD for both primary (source water) and secondary disinfection, however, it is not being considered further because of potential severe odour concerns and health concerns related to byproducts produced by the process. Ultraviolet light is not widely used in large water systems for primary disinfection and is not used as a secondary disinfectant because it cannot provide a disinfectant residual in the distribution system to control bacteria levels. Potassium permanganate produces a pink to grey colour and black precipitate to the water making it unacceptable as a secondary disinfectant.

Conventional filtration of the water would reduce sediment and organics which contribute to bacterial regrowth and would reduce the chlorine demand in the water distribution system thereby reducing the number of rechlorination stations in the region.

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Ozone can be used as a primary disin-fectant, but not as a secondary disin-fectant.

Ozone and biologi-cal filtration produce highest quality water and minimize the use of chlorine or chloramine.


Ozone is a very effective primary (source water) disinfectant and has been extensively tested in recent pilot plant studies by the GVRD's consultants and reviewed by a team of European and North American experts in 1991-1992. To be effective as a primary disinfectant the water cannot contain even moderate turbidity (cloudiness) and, therefore, ozone must be used in conjunction with filtration. Future treatment plant planning has allowed for the possible installation of ozone. Testing, however, has shown its use could actually magnify the bacterial regrowth problem by breaking down naturally occurring organics and producing more bacterial food, which in turn may require greater amounts of secondary disinfectant to control increased bacterial regrowth. Ozone is never used as a secondary disinfectant because it cannot maintain a residual out in the distribution system.

Biological filtration could be employed along with ozone to reduce this food source. This technology would produce a water which is of very high quality with low bacterial food levels, thereby allowing the lowest amount of disinfectant possible. Some disinfectant would still be required, as recommended by public health authorities, to protect the water system from the growth of pathogenic organisms that may enter from cross contamination and sanitary breach. Minimizing the secondary disinfectant in the drinking water is currently not an objective of the DWQIP as it is not a requirement of the Canadian Drinking Water Quality Guidelines. However, if it is desired to go beyond the Canadian Guidelines and to provide water with the least disinfectant residual and disinfection byproducts, then the best available technology would be biological filtration (ozone enhancement of biologically active filters). A secondary disinfectant, although at low residual level, would still be required in the distribution systems to control the spread of contamination and low bacteria regrowth potential. The use of a secondary disinfectant is commonly used throughout the world as indicated in Attachment II. Of note are the North American cities using ozone as a primary disinfectant e.g., Montreal, Los Angeles, San Francisco, and Hackensack, New Jersey, each city still uses a secondary disinfectant.

6.3 Health

Health issues associated with secondary disinfection are related to the effective control of microorganisms in the distribution system and to the reduction of disinfection by-products.

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Chloramine is more effective than chlorine at controlling bac-teria regrowth in Surrey.

There is a world-wide trend to lower disinfection by-product levels.


6.3.1 Microbiological

Effective control of microorganisms is necessary to meet the microbial standards in the B.c. Safe Drinking Water Regulation and the Canadian Drinking Water Quality Guidelines.

In general, chloramine has been found in the Surrey secondary disinfection demonstration areas to be more effective in controlling microorganisms than chlorine as it persists longer and inactivates microorganisms in pipe biofilms more effectively. However, with multiple rechlorination stations positioned throughout the GVWD, chlorine is expected, along with increased cleaning, flushing and circulation and smaller rechlorination zones, to meet the microbial standards of the Safe Drinking Water Regulation. As stated previously, there is a legal requirement for the GVWD and its member municipalities to meet the Safe Drinking Water Regulation with potential legal penalties for noncompliance.

6.3.2 Disinfection By-Products (DBPs)

Trihalomethane (THM) is classified as a probable carcinogen by Health Canada based on studies that have shown that high doses of chloroform, which is the principal THM in GVRD water, has caused cancer in laboratory animals.

On April 10, 1992, Health Canada released a formal proposal to revise the drinking water guideline maximum acceptable concentration (MAC) for THM from a 350 /lglL maximum to a 50 /lgIL average. An agreement has recently been reached between the provinces and Health Canada on an interim MAC (!MAC) of 100 /lgIL average. An !MAC has been established rather than a MAC until concerns regarding other disinfection by-products are addressed, and then the earlier proposal of 50 /lglL will be reconsidered. Another chlorine disinfection by-product group that is scheduled for review by Health Canada is the haloacetic acid (HAA) group which is also a suspected carcinogen.

World and North American standards for these compounds are seeing a lowering of acceptable levels. The current maximum contaminant level (MCL) for THM in the USA is 100 /lglL, however, it is proposed by USEPA to lower this value. The USEP A has reached a tentative 11 consensus" on a proposed regulatory rule for disinfectants and disinfection by-products (DIDBP). Two stages are proposed for the rule. The new Stage I MCL for THM is 80 /lglL (effective 1998) and the Stage II (effective 2002) level is 40 /lglL. The Stage I MCL for total HAA is 60 /lglL and for Stage II, it is 30 /lglL.

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Combined ozona-tion, filtration and chloramination produced lowest DBPs.

Filtration is re-quired at Seymour and Capilano to solve high turbidity problem.

Filtration is re-quired at Coquit-lam to reduce DBPs only if rechlorination is selected.

Medical Health Officers favour chloramination.


With chloramination, simulated distribution system testing conducted as part of the Predesign and Planning Studies has predicted that THM levels in the GVWD supplied water would meet the proposed Canadian Guideline of 50 flglL as indicated earlier in Exhibit A-2. If the rechlorination option is selected, THM levels, based on bench scale testing, are expected to range between 80 and 130 flglL depending on residence times of two to seven days within the distribution system (chlorine disinfection byproducts increase with time in the distribution system while chloramine halts the reaction initiated by the primary disinfection process). Total HAAs for chloraminated water are expected to be about 20 flglL and for rechlorinated water about 50 flglL depending on residence time. Pilot filtration testing indicates that, with filtration, THM levels with rechlorination would be reduced to levels below the proposed Canadian Guideline of 50 flglL. Likewise, total HAA levels would be lowered to below 30 flglL for filtered rechlorinated water. As indicated in Exhibit A-2, a combination of ozonation, filtration and chloramination produced the lowest levels of THMs and HAAs.

It is probable, based on the results of pilot testing, that unfiltered, rechlorinated GVWD water, on an average basis, would meet the Canadian THM IMAC of 100 flglL, but would clearly not meet the proposed 50 flglL. However, some areas of the region's water system would likely exceed the 100 IlglL level.

The Drinking Water Quality Improvement Plan (DWQIP) indicates that frequent high turbidity events at Capilano and Seymour sources inhibit the effectiveness of primary disinfection and, therefore, filtration is required to ultimately meet the Canadian Drinking Water Quality Guidelines. Although the Coquitlam source also has occasional episodes of high turbidity (i.e. > 5 NTU) the duration is usually short and some easterly transfer of water is possible to mitigate these events. Therefore, filtration of the Coquitlam source had not been proposed in the DWQIP. However, as indicated above, filtration of all three sources would be required in order to meet future Canadian THM guidelines if a MAC of 50 flglL is established in the future, and if chlorine is used as the secondary disinfectant.

6.3.3 Position of Medical Health Officers

It should be recognized that the proposed THM levels are guidelines and there are presently no legal liabilities for failure to meet these Guidelines. However, the region's Medical Health Officers, who have authority under the B.c. Health Act, have recommended that the Canadian Guidelines for all drinking water quality parameters should be met as closely as possible.

The Medical Health Officers (MHOs) in the region have unanimously indicated their preference for the use of chloramination over rechlorination as the method for secondary disinfection. However, if rechlorination is

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Both chloramine and chlorine are toxic to fish.

Models indicate that the exposure concentrations (riskto fish) for chloramine will be 2.5 to 19 times higher than chlorine.

Recent testing indicates that the relative risk may be reduced to 1 to 8 times higher than chlorine.

Pipe breaks and fugitive releases of drinking water can not be completely mitigated.


selected and the THM guideline is lowered, the MHOs are recommending implementation of filtration as soon as it is possible (see November 16, 1993 letter - Attachment Ill).

6.4 Environment

The environmental issue related to secondary disinfection is the potential for impact to fish and other aquatic organisms and resultant legal liabilities with the release of disinfected water to the receiving environment. At the concentrations of disinfectant that are proposed for the water distribution system, both chlorine and chloramine are toxic to fish and fish food organisms such as aquatic invertebrates. The potential for environmental impact was heightened with the regulatory agencies and the public, particularly with respect to chloramine, when fish kills occurred as a result of release of chloraminated water from two separate water main breaks in the secondary disinfection test area in the City of Surrey.

To determine the magnitude differences between chloramine and chlorine, the Environmental Impact Assessment (Stage II) Report presented mathematical models of various chlorine/chloramine release scenarios based on 1992 treatment levels (1.0 mg/L chlorine and 2.5 mg/L chloramine). The models showed that under some circumstances either disinfectant can cause impacts, including fish kills. However, chloramine will present a higher risk than chlorine because the exposure concentrations in a receiving water body were from 2.5 to 19 times higher for chloramine than for chlorine during a release event and will result in greater impacts. The frequency of impact event would also be higher for chloramine than chlorine. However, since mid-1993, the South Surrey chloramination facility has been successfully controlling bacterial regrowth with a chloramine concentration of 1 mgIL leaving the treatment plant (residuals ranging from 0.4 to 0.8 mg/L in the distribution system). If this continues to be successful, exposure concentration would be reduced to about 1 to 8 times higher for chloramine than chlorine.

Releases of either disinfectant from most sources can be mitigated except for spontaneous water main breakslleaks and fugitive releases such as lawn watering and car washing. Spontaneous water main breaks cannot be completely mitigated because the time and location of the break cannot be predicted. In the event of a water main break, either chlorine or chloramine could reach concentrations that would impact the aquatic environment in a number of release scenarios, but impacts from chloramine would occur for a wider range of circumstances. Fugitive releases from domestic sources (lawn watering, car washing) are difficult to eliminate or mitigate. Although under some circumstances releases of either disinfectant from domestic sources could cause impacts, chloramine would pose the greater

A-24

, ..... I

Potential legal liabilities to GVRDandlor member munici-palities are much higher with chloramine.

Government En-vironment agen-cies are opposed to chloramine.

The taste of the water would be less chlorinous with chloramine.


risk because of its persistence in the storm water systems. Dechlorination of all storm water outfalls is theoretically possible but the cost would be greater than the rechlorination option (see Section 6.6). Dechlorination units can be installed for storm outfalls on the more sensitive streams. (Ten million dollars has been allowed for this.) Detailed environmental inventories would be undertaken to establish these locations.

Ammonia, a component of chloramine that can be released during dechloramination, would not be released at levels that could impact the receiving environment and is not a significant environmental issue.

The GVWD and/or member municipalities, staff and officials could be charged under the Fisheries Act, if a fish kill occurred as the result of a release of disinfected water, especially if it were released directly from the distribution system (e.g., water main breaks/leaks). Charges are less likely with the use of chlorine than with the use of chloramine. The fines under this Act are substantial (up to $1 million), and the Act includes provisions for jail sentences. Legal liability could also be incurred under the provincial Waste Management Act and Spill Reporting Regulations. Civil action for loss of income to the fishing industry may also be a liability.

Department of Fisheries and Oceans, Environment Canada, and B.C. Ministry of Environment advise that fisheries enhancement is not an acceptable form of mitigation as offsetting an anticipated pollutant impact by means of artificial propagation, physical habitat enhancement, or restocking, is not biologically sound and is not consistent with the National Policy for the Management of Fish Habitat. DFO requires that mitigation of chemical impacts must be conducted at source with an emphasis on the prevention of pollution.

6.4.1 Position of Government Environment Agencies

The Ministry of Environment has officially stated their opposition to the use of chloramination. Environment Canada and the Department of Fisheries and Oceans (DFO) have serious concerns about the use of chloramination in the region (see August 6, 1993 letter - Attachment ill). Section 6.8 describes the ultimate authority available to DFO to stop or modify the implementation of any project likely to cause an impact on the fisheries resource.

6.5 Water Users

Water users include domestic consumers and various industrial users who could be impacted by the implementation of secondary disinfection. Issues affecting water users include affects on the palatability of drinking water and requirements for certain users to dechlorinate their water.

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Users affected by chlorine or chloramine can remove them by treatment.

Dechlorination will be required for both disinfectants if discharge is to local water course.

Water treatment cost is lower for chloramine.


Chloramine treated water is expected to be more aesthetically pleasing to consumers as it has a significantly less chlorinous taste than rechlorinated water. The potential health impact of poorer tasting water is reflected in a report to Burnaby Council from their Medical Health Officer, Dr. A. King, which states:

"The primary goal oj providing a microbiologically saJe drinking water to the public may be significantly under-mined if an increased chlorinous taste and odour results in the proliferation oj poorly maintained home point-oj-use water filters. "

Experience in the Surrey test areas is almost no taste and odour complaints in the chloramine area and many complaints in the rechlorinated area.

Water users that require chlorine-free water (e.g. haemodialysis facilities, aquaculture operations, home aquarists and breweries) and do not have onsite dechlorination will need to implement treatment to avoid impacts from either secondary disinfection option. Many of these users currently dechlorinate their water and will not be significantly impacted, although some systems might require upgrading or retrofitting to offset the increase in chlorine concentrations. A number of users (e.g. aquaculture operations) might need to install ammonia removal facilities for the extra ammonia over that produced by fish wastes, if chloramination is implemented.

Certain municipal and industrial water users that discharge GVWD water as cooling water directly to receiving water or to storm sewers will need to dechlorinate ,their water prior to discharge. This requirement will be the same whether the secondary disinfectant is chlorine or chloramine.

6.6 Cost

There is a significant total cost difference between the secondary disinfection alternatives and the potential for a substantially greater cost difference. Of the two options proposed for secondary disinfection, rechlorination is the more expensive, with estimated construction costs ranging from $40 to $50 million and annual operating costs from $3 to $5 million. These disinfection costs would be reduced by 30 to 50 percent if the source waters were filtered first. The estimated cost for chloramination is approximately $1 to $2 million for construction and $0.5 to $0.6 million for annual operation with no cost reduction if the sources were filtered.

In addition, if the rechlorination option is selected and mitigation of disinfection by-products (DBPs) is required, then filtration of the Coquitlam

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Appendix A- Drinking Water Quality Improvement Plan

Exhibit A-4 Drinking Water Treatment Costs

(1993 Dollars)

Average Household2

Water Cost Per Year

Additional DWQIPI and Other Household

Advanced Water Capital Cost Water Cost Treatment Process ($ Million) Per year Chloramine Chlorine

Current Average --- --- $130 Water Cost 1993

Projected GVWD --- $40 $170 Base Increase for Non-Water Quality Works (1993 - 200W

DWQIP Phase 14 $130 - $170 $20 - $30 $190 $200

DWQIP Phase 2 - $150 $30 $220 $230 Filter Seymour5

DWQIP Phase 3 - $200 $40 $260 $270 Filter Capilano5

Total DWQIP Cost $480- $520 $90 - $100 $260 $270

Filter Coquitlam $360 $75 $335 $345

Ozone (filtration re- $60 $15 $350 $360 quired first)6

Biological Filtration $400 $85 $4357

Total Cost Including $1,300 - $1,340 $4357

Additional Treat-ment Processes

DWQIP - Drinking Water Quality Improvement Plan. 1. 2. 3. 4.

Average household costs include capital and operating costs. Does not include projection for municipal increases to year 2000.

5. 6. 7.

DWQIP Phase 1 includes primary disinfection using either chloramination or rechlorina-tion, the water quality share of the Westerly Transfer facilities and $10 millionfor mitigat-ion costs for chloramination. Estimated cost assumes 50% cost sharing with Province. Phases 2 and 3 costs assumes no cost sharing with Province. Neither ozone nor biological filtration eliminate the need for secondary disinfection. Assumes no rechlorination stations required as chlorine demands minimized. Therefore, DWQIP Phase I component would not require the extra $40 million capital cost for rechlor-ination secondary disinfection.

water source, in addition to the other two sources being filtered under the DWQIP, may be required at an estimated cost of $360 million for construction and $8 million for annual operation. These costs depend on the location of the filtration facilities.

Exhibit A-4 summarizes the costs of the Drinking Water Quality Improvement Plan (DWQIP), and more advanced water treatment technologies, indicating the annual cost of each option to the average household. For the consumer, the cost difference between rechlorination and chloramination would amount to about $10 per household per year, excluding the cost of filtering the Coquitlam source. The cost of filtering the Coquitlam source is $75 per household per year.

Either secondary dis-infectant will result in

similar Illitlgation costs for emergency response and other municipal releases, industrial discharges and most other water users. However, the need for ammonia removal might increase point-of-use water treatment costs for a few water users, if chloramine is selected as the secondary disinfectant. In addition, amendment of the GVRD Sewer Use Bylaw and corresponding municipal bylaws may be necessary to allow cooling waters

A-27

Mitigation costs are higher for chloramine and are difficult to estimate.

Rechlorination will take longer to implement than chloramine.


to be discharged to the sanitary sewers or be dechlorinated prior to discharge to the environment.

Chloramination will have significantly higher mitigation costs than rechlorination in the area of storm water discharges. These costs could range from $5 million to $10 million more in capital expenditure and $1 million in annual operating costs, if storm water dechlorination units are installed only in highly sensitive areas. Installation of dechlorination units on most or all storm water outfalls could range from $55 million to $105 million, and are not considered practical or cost effective.

Chloramination will also have significantly higher costs than rechlorination in the areas of fisheries resource compensation and potential legal prosecution liabilities though these costs have not been quantified. (Actual costs of legal liabilities and potential damage to fisheries resources cannot be realistically estimated. However, public input strongly requests that these factors be considered in the final selection of a secondary disinfectant).

6.7 Implementation

Rechlorination would take longer to implement than chloramination. Rechlorination would take eight to ten years to implement due to the extensive design, siting studies and public consultation required for the rechlorination stations. Chloramination could be implemented in approximately three years, without the same level of difficulty in facility siting.

Although the EIA has determined that chloramine is a larger risk to the environment than rechlorination it was not practical to quantify the actual impact that chloramination would or might have on the environment. In light of this and with the advantages of chloramine regarding health issues, palatability to consumers, and overall costs, full scale implementation of chloramination could be tried for relatively little cost. Implementation could be reversed if the level of environmental impact were unacceptable.

Such a trial period would allow a more thorough evaluation of the chloraminated system's impact to the environment. Storm water mitigation facilities would be added following the trial period, if required and if chloramination were to be continued. However, some units should be installed during the trial period to evaluate their effectiveness. Those mitigation facilities required for either secondary disinfectant, e.g. cooling water discharges, should be installed before a chloramine trial begins.

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-

Potential for contravention of the Fisheries Act is higher with chloramine.

DFOcould potentially stop construction of chloramination facilities.


6.8 Potential Prosecution and Legal Liability

Liabilities are usually financial but can involve jail sentences and may arise by statute or common law in the form of convictions for environmental offenses, administrative orders by government agencies (e.g. cleanup orders), and civil action. The Environmental Impact Assessment (Stage II) Report identified the following potential liabilities associated with the GVWD's proposed secondary disinfection.

o Provisions in the federal Fisheries Act represent the most significant liabilities related to proposed secondary disinfection. The GVWD and/or member municipalities could be prosecuted if a fish kill occurred as a result of a release of disinfected water, especially for releases directly from the distribution system (e.g., water main breakslleaks). Fines of up to one million dollars could be realized and there are provisions for jail sentences. The liability related to the Fisheries Act appears to be much greater for chloramine than chlorine arising from the greater stability of chloramine in the receiving environment.

0

0

In addition, the Fisheries Act gives the Minister the authority (with the approval of the Governor in Council) to require modification to or stop any work that is likely to cause a deleterious substance to be deposited in waters frequented by fish.

Failure to implement secondary disinfection could result in prosecution under the B.C. Health Act's Safe Drinking Water Regulation.

o Other potential liabilities are related to provisions in the federal Transportation of Dangerous Goods Act, provincial Waste Management Act, and Spill Reporting Regulations.

6.9 EIA Conclusions

Secondary disinfection of drinking water is required in order for the water to consistently meet the microbial standards of the British Columbia Safe Drinking Water Regulation and Canadian Drinking Water Quality Guidelines and to provide a degree of protection against contamination of the water supply from pathogenic microorganisms that may enter the system as a result of accidental water main breaks or back siphonage. Chloramine and chlorine are generally accepted by the drinking water industry as the only secondary disinfectants that are appropriate for the GVWD. Studies conducted by the GVRD show chloramine to be the more effective secondary disinfectant.

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Chloramine is a more effective disinfectant and is more palatable to consumers.

Chlorine is more acceptable from an environmental perspective.


Chloramine has advantages with respect to health issues, palatability to consumers, and overall costs of implementation. However, the disadvantage of chloramine is that it has a higher risk of impact to the aquatic environment. This impact could have significant legal ramifications as release of chlorinated or chloraminated water would contravene the federal Fisheries Act.

Chlorine is more acceptable from an environmental perspective because the frequency and magnitude of its impacts will be less than those from use of chloramine. The risk of contravening the Fisheries Act with spills, although present, is much less with rechlorinated water than with chloraminated water. Health concerns related to coliform bacteria regrowth can be met with rechlorination, however, filtration of the Coquitlam source, in addition to Capilano and Seymour may be required to satisfy future guidelines for disinfection by-products. A comparison of the two alternative secondary disinfectants is summarized on Exhibit A-S.

A-30


Exhibit A-5 Comparison of Rechlorination and Chloramination

Rechlorination Chloramination

Environmental Impact [J Severe to nil depending on CJ 1 to 20 times impact of receiving water quality and rechlorination depending on extent of aquatic organisms disinfectant levels, receiving present. water quality and extent of

[J DFO prosecution potential is aquatic organisms present.

low. [J DFO prosecution potential is high.

Health Impacts

Bacterial Disinfection Fair to good (if persistent) Good

Disinfection By-Products Filtration required to meet future Filtration not required to meet (THM) Concentrations possible guidelines. possible future guidelines.

Impact to Water Users

Without Mitigation Low Low

With Mitigation Nil Nil

Aesthetics

Taste and Odour More chlorinous than presently. Nil to slight chlorinous.

Costs (1993 Dollars)

Capital Costs of Secondary $40 - $50 million 1 $1 - $2 million Disinfection

Operating and Maintenance for $3 - $5 million 1 $0.5 - $0.6 million Secondary Disinfection

Filtration at Seymour and $350 million capital, $14.6 million $350 million capital, $14.9 million Capilano Sources (Phase 2 and operating and maintenance. operating and maintenance. 30fDWQIP)

Potential for Filtration Coquitlam: $360 million capital Nil Need over DWQIP and $8 million annual operating Nil

Mitigation Costs Significant More significant perhaps $5 - $10 million capital more ($10 million assumed)

Implementation

Time Required 8 - 10 years and more iffiltration is 3 years added.

Station Siting Studies Required Yes, throughout region. No, except at 3 sources

Stations Required 50 - 60 throughout the GVWD2 3 near sources

1. These costs would be reduced by 30% to 50% if the water is filtered. 2. Twenty to thirty percent rechlorination stations would be required if the water was filtered.

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Public needs more information on alternatives before selection of second-ary disinfectant.

Public support for filtration needs to be determined.


Section 7.0 Public Consultation

In 1992 the GVWD Water Committee and the Administration Board established a consultation program on regional drinking water issues. The Consultation Framework for this program established the topics to be considered in the consultation and the methods that would be used to gather public input on these issues.

The topics include the Drinking Water Quality Improvement Plan (DWQIP), Water Supply and Conservation, and Watershed Management. The methods to be used to gather public input include written submissions, surveys, community meetings, feedback from consultation events such as open houses and workshops, telephone calls, Council briefings, response to the consultation newsletter and meetings of the Regional Water Advisory Committee. Attachment I summarizes the public consultation activities carried out to date on the DWQIP and EIA.

Input to the public consultation process indicated that the public has a low level of awareness of drinking water quality concerns. They would also like more information before a choice is made between chloramination or rechlorination as a secondary disinfectant. When asked to select between the two in mid-199:3 surveys, the community was divided with approximately one third choosing chloramination, just over one third choosing rechlorination and the last third saying either that they do not know or that they prefer some other alternative.

Written responses from the public showed strong opposition to the use of chloramine. Most of these responses were through form letters and petitions and many responded to news media reports, not to the EIA report and, therefore, it is difficult to determine at this time what option the general public prefers.

Additional public consultation is required to determine which secondary disinfectant should be used and the implementation schedule (when filtration should proceed) for the DWQIP. In addition to the limited public support for either secondary disinfectant, there has not been enough public consultation to determine how much public support exists for the costs to implement filtration of the Seymour and Capilano sources (Phases 2 and 3 of DWQIP) and the costs of the program in general.

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'I

The goal of the DWQIPisto provide drinking water that meets standards.

Greater Vancouver is the only major centre in Canada that is not meeting the Canadian Guidelines.

Full implementa-tion of the DWQIP is required to meet drinking water standards.

Section 8.0 Conclusions

8.1 Conclusions


The overall objective of the DWQIP is to provide drinking water to the region's 1.6 million residents that meets the Guidelines for Canadian Drinking Water Quality (safe, clean, and aesthetically pleasing). Environmental concerns associated with secondary disinfection, identified in the EIA, require that an acceptable balance be found between health, aesthetics, environment and cost.

Concerns regarding our region's drinking water quality were first raised in 1984. The GVRD has completed numerous studies since that time and is now in a position to start detailed design and construction of facilities to improve water quality.

Greater Vancouver is the only major centre in Canada that does not meet the Guidelines for Canadian Drinking Water Quality and drinking water in the Region is not in compliance with the recently introduced British Columbia Safe Drinking Water Regulation.

There are four drinking water quality issues that must be addressed to meet the Canadian Guidelines as follows:

o Potential for waterborne disease (giardiasis), o Seasonal bacterial regrowth in the Region's water distribution sys

tems, o Turbidity (cloudiness) above 5 NTU which compromises primary

disinfection, and o Corrosive nature of the water.

Full implementation of the DWQIP, either in phases or completely, is required to ensure GVWD supplies safe water that complies with the Canadian Guidelines. Implementation of Phase 1 of the DWQIP is expected to provide compliance with the British Columbia Safe Drinking Water Regulation.

Public health risks related to high turbidity (primary disinfection is ineffective above a turbidity of 5 NTU) will continue until Phases 2 and 3, filtration of Seymour and Capilano, are completed.

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At this time, Phase 1 would improve water quality stan-dards compliance substantially with Phase 2 (Seymour filtration) adding significant benefits.

Chloramine is a more effective se-condary disinfec-tant, tastes better and is lower in cost, but is a high-er risk to the en-vironment and the fishery resource.


Filtration of Seymour source (Phase 2) and replacing high turbidity Capilano water with the Westerly Transfer of Coquitlam water Phase 1 would reduce the number of days of high turbidity on average, from 18 days to 4 days per year. This is an interim solution as eventually increased water demand due to population growth in the region will not allow the westerly transfer of water from Coquitlam. At this point in the future, Capilano source will require filtration in order to maintain the highest water qUality.

Filtration of the Seymour source, in addition to the reduced Giardiasis risks discussed above, will eliminate the coloured water (high iron) problems associated with this source; it will reduce the number of rechlorination stations required and disinfection by-products in the Seymour service area if the rechlorination secondary disinfection option is selected; allow evaluation of the anticipated benefits of filtration on bacterial regrowth; and produce aesthetically pleasing low turbidity drinking water on a consistent basis.

Filtration of Capilano (Phase 3) would have very similar benefits but the region-wide improvement of water quality would be marginal at this time, compared to improvements provided by Phases 1 and 2.

The nonfiltration improvements (Phase 1) would improve compliance with water quality standards from an estimated 50 percent to 80 or 90 percent with chloramination or 70 to 80 percent with rechlorination. Filtration of Seymour (Phase 2) would increase compliance to about 95 percent and filtration of Capilano would further increase compliance to almost 100 percent based on chloramine secondary disinfection (rechlorination compliance is expected to be less).

Predesign and planning studies for DWQIP Phases 1, 2, and 3, respectively, have been completed to determine accurate cost estimates for the program.

The findings of the EIA of Secondary Disinfection can be summarized as follows:

o

o

Chloramine has advantages with respect to health issues, palatability to consumers, and overall costs of implementation. However, the disadvantage of chloramine is that it has a higher risk of impact to the aquatic environment. This impact could have significant legal ramifications as release of chloraminated water would contravene the federal Fisheries Act.

Rechlorination (higher chlorine levels) is more acceptable from an environmental perspective because the frequency and magnitude of

A-34

,"-

"

, \

Drinking water standards can be met with rechlo-rination and fil-tration and it poses less risk to the environment and the fishery resource.

Biological filtra-tion will reduce the amount of disin-fectant required to treat the water, but it is more costly.

Public is generally not aware of drink-ing water quality concerns.

0


its impacts will be less than those from use of chloramine. The risk of contravening the Fisheries Act with spills, although present, is much less with rechlorinated water than with chloraminated water. B.C. Health Act's requirements can also be met with rechlorination, however, filtration of all sources may be required to satisfy future drinking guidelines.

Filtration to a small degree and ozone with biological filtration to a greater degree will reduce or minimize the amount of secondary disinfectant required in the drinking water but will not eliminate it altogether. Allowances have been made for future addition of ozone/biological filtration if required, however, at this time these components are not needed to meet the Canadian Drinking Water Quality Guidelines and the additional cost of these technologies would increase the cost to the consumer.

A summary of capital costs and household costs of the basic DWQIP, secondary disinfection options and more advanced water treatment processes is presented in Exhibit A-4 on page A-27.

A considerable amount of public consultation has been carried out to date. The findings of the public consultation reveal the following:

o The public is generally not aware of the drinking water quality concerns identified in the DWQIP and that the Region's drinking water does not comply with the provincial regulations or federal guidelines.

o In mid-1993 surveys, the public was split three ways regarding the choice of secondary disinfection with just over one third preferring rechlorination, one third choosing chloramination and the last third saying either they do not know or prefer some other alternative.

o Written and telephone response to the EIA of Secondary Disinfection showed strong opposition to the use of chloramines.

o Additional public consultation is required to determine which secondary disinfectant should be used and the implementation schedule for the DWQIP.

o In addition to the limited public support for either secondary disinfectant, there has not been enough public consultation to determine how much public support exists for the costs to implement filtration of the Seymour and Capilano sources (Phases 2 and 3 of DWQIP) and the costs of the program in general.

A-35


Glossary

Alkalinity - the capacity of water to neutralize acids.

Bacterial regrowth - the growth of bacteria in a water distribution system after initial disinfection.

Biological filtration - advanced treatment process utilizing biologically active sand or carbon to remove biodegradable organic carbon from drinking water (Preozonation is usually used to enhance biological activity). This food source could otherwise sustain the growth of potentially harmful microbes in the distribution network.

Buffering - the potential of a solution to offer resistance to changes in pH as acids or bases are added to or formed within the solution.

Chloramine - compound of organic or inorganic nitrogen ammonia and chlorine at low concentrations in water.

Chlorination - the application of chlorine or chlorine compounds at low concentrations to water, generally for the purpose of disinfection.

Chlorine - a chemical available in gaseous or liquid (sodium hypochlorite or bleach) form, commonly used as a water disinfectant.

Chlorine dioxide - produced by reacting chlorine, sodium hypochlorite, and hypochloric acid together and used as a water disinfectant.

Chlorine residual - chlorine remaining in the water at the end of a specified period of time as combined or free chlorine.

Chloroform - most common trihalomethane compound formed via reaction of chlorine with various organics during drinking water treatment.

Disinfection by-Products (DBPs) - compounds formed when a chemical disinfectant (e.g. chlorine) reacts with organic compounds in water. DBPs referred to in this report are Trihalomethanes and Haloacetic Acids.

Giardia - an organism that may be carried by animals and humans. Giardia may be found in many surface waters and causes a waterborne disease called giardiasis (beaver fever).

Haloacetic Acids (BAA) - group of disinfection by-products identified as low risk carcinogens.

A-36


Hardness - caused by divalent metallic cations such as calcium and magnesium capable of reacting with soap to form precipitates. Hard waters require considerable amounts of soap to produce a foam or lather.

Heterotrophic plate count (HPC) - A broad group of bacteria, including , . nonpathogens, pathogens and opportunistic (grow under optimum conditions) pathogens indicative of poor general biological quality of the drinking water.

Kidney Dialysis - the cleansing of a medical patient's blood supply using equipment which duplicates the function of the human kidney. This is accomplished by pumping the blood through a semipermeable membrane.

Micrograms per litre (J.lgIL) - a measurement of concentration in water, essentially equal to parts per billion (ppb).

Milligrams per litre (mgIL) - a measurement of concentration in water, essentially equal to parts per million (ppm).

l\1L/day - a measurement of water flow, in millions of litres per day.

Nephelometric Turbidity Unit (NTU) - measurement unit for turbidity.

Ozone - unstable gas generated on-site by high voltage electrical discharges through air or oxygen gas. Injected into the water, ozone is highly effective against viruses, bacteria and parasites.

Pathogens - disease causing microorganisms (bacteria, viruses and parasites).

pH - a measure of acidity in water. On a 0 - 14 scale, 7 represents neutrality, decreasing values indicate increasing acidity and increasing values indicate more alkaline conditions. Vinegar (acetic acid), for example, has a pH of2.5.

Potassium permanganate - a strong oxidant which imparts a pink colour to the water.

Primary disinfection - initial disinfection of a water supply.

Secondary disinfection - provision of a disinfectant residual in a water distribution system through redisinfection or stabilization of the primary disinfectant.

A-37


Total coliform - a group of bacteria, widespread in nature, that is used to determine the potability (safe to drink) of water. Low levels of total coliform bacteria, although not desirable, are acceptable in drinking water.

Trihalomethanes (THMs) - a specific group of DBPs. Research has indicated a very low level of carcinogenic risk to humans from ingesting THMs in drinking water. A limit for the level of THMs in drinking water has been set in the Guidelines for Canadian Drinking Water Quality.

Turbidity - a cloudy condition in water caused by the presence of suspended matter, resulting in the scattering and absorption of light.

Ultraviolet light - biocidal radiation provided by low pressure mercury vapour lamps used for disinfection of drinking water.

A-38

In 1990 there were 1,000 calls receiv-ed from public, mainly concerned with high turbidity.


Attachment I DWQIP/EIA Public Consultation

This attachment summarizes public consultation activities and data such as phone line, information distribution, and presentations and workshops.

GVRD Water Quality Inquiry Phone Line (Quality Control Section)

The GVRD has for many years operated a "Water Quality Inquiry" phone line. In recent years the public has shown an increasing willingness to phone for information on water quality as well as to complain about the quality of our drinking water. The following is a brief summary of information gathered through this phone line over the last three years.

During 1990, Quality Control staff fielded in excess of one thousand calls related to water qUality. Of these, the majority were related to the high turbidity events at the Seymour and Capilano sources which occurred during November and December of 1990. Calls related to chlorine tastes and odours were the next most significant group. About one hundred calls on this issue were answered by Quality Control staff in 1990. Calls on green stains (related to copper corrosion) were significant but slightly less frequent than those for chlorine tastes and odours. Although the GVRD does not add fluoride to the drinking water, inquiries related to fluoride in the water were quite common, as were calls dealing with other water quality issues such as bottled water, water filters, and news items.

ExhibitA-6 GVRD Water Quality Inquiry Phone Line

Overall water quality in terms of turbidity improved in 1991 and 1992 and as a result there were fewer inquiries and complaints. Chlorine taste and odour, green staining (corrosion), and turbidity typically rank at the top of complaints received as indicated in Exhibit A-6. Yellow water complaints are associated with high iron mostly in Seymour water, which is not experienced every year.

Summary 1991 - 1992 1991 1992

Total Number of Calls 764 747 Inquiries 430 423 Complaints 334 324

Nature of Inquiry or Complaint Chlorine (taste and odour) 123 90 Green Staining, Corrosion 96 52 Turbidity 194 168 Fluoride 45 83 Hardness 20 46 Yellow Water 62 7 Taste and Odour (undefined) 46 50 Water Quality Information 52 63 Miscellaneous Complaints 61 45 Miscellaneous Inquiries 65 124 BTK (Gypsy Moth spraying) --- 19

A-39


Regional Drinking Water Cons Line and Information System

ExhibitA-7 Summary of Information Requests and Comments Made Throughout the

Regional Drinking Water Consultation Program to September, 1993 Total Number of

Requests for Information About: Persons Calling Drinking Water Quality Improvement Plan (Report or Executive Summary) 34 Predesign and Planning Studies (Report or Executive Summary) 26 EIA on secondary disinfection (Reports or Executive Summary) 353 Chloramine and where it is being used 5 Rechlorination 48 Water contaminants 1 Acidity of water and corrosion control program 9 Safety of water 16 Sources of water 2 Chemicals used in the water including fluoride 37

Discoloration in sinks 25 Water restrictions and conservation program 95 Role of provincial government in water issues 1 Hardness 18 Testing of water 28

Comments on:

Concerned about the effects of chloramine on fish 1 Concerned that chlorine in the water can cause cancer 1 Prefers chloramine over chlorine 2 Concerned about chlorinated water in fish ponds and aquariums 1 Dislike the smell of the water 19 Dislikes chlorine taste 5 I suspect I have a chloramine allergy 1 Chlorine allergy 1 Concerned about effects of chloramine on nematodes in raspberry growing I Markets water purifiers and believes these are the solution to quality problems 2 Concerned about the colour of the water 36 Support filtration at source 8 Point Roberts' use of our water and are they going to pay for DWQIP 1 Should not spend money on AirCare when the water is dirty 1

GVRD should have planned ahead for growth 3 Has GVRD looked at other methods other than chlorine and chloramine? 1

Limit growth 1 Supports Ozone options for water treatment 4 Not aware of public health concerns regarding regrowth, Giardia, low pH, 1 turbidity

ultation Phone

In addition to the permanent water quality mqUIry phone line a regional drinking water consultation phone line, and information system was created to handle a broader range of information requests relative to the DWQIP and the EIA. Exhibit A-7 summarizes the number of phone calls and information requests received to date. Exhibit A-8, on the next page, summarizes the breakdown of information requests by the public and documents sent.

Public Awareness of Water Quality Problems

There is a low level of awareness of drinking water quality issues. Only 25 percent of respondents in the attitude research (random telephone survey) said that water quality was a problem. Although the public is not

A-40


Exhibit A-a Summary of Information Distributed

(December 1992 to October 1993)

Number of Documents

Title PublicI Government2

Environmental Impact Assessment

Stage 1 - Report 76 60

Stage 2 - Report 56 60

Executive Summary - Stage 1 120 34

Executive Summary - Stage 2 167 34

Predesign and Planning

Reports 40 45

Executive Summary 19 34

Drinking Water Quality Improvement Plan

Reports 10 See Note 3

Executive Summary 24 See Note 3

Others

Reflections Newsletter (December 13,0004 500 1992 and September 1993 issues contained information on the DWQIP and the EIA)

DWQIP Discussion Paper 2,5004 500

I. Includes reports sent to all public, university and college libraries within the GVRD(33).

2. Reports sent to government agencies including: municipal clerks, municipal water quality technical committee (WQTC), medical health officers, municipal environmental officers and municipal councilors, GVRD Water Committee and Board members.

3. Previously sent in 1990. 4. There are 1,400 persons included on this list who have requested to be on the

GVRD Water Consultation mailing list.

aware of the water quality issues facing our region, the City of Vancouver, at the City Plan Ideas Fair in May, 1993, found drinking water quality and conservation improvements to be the most important of 14 issues to the public. A low level of awareness of water quality issues was also indicated in the December 1992 focus group discussions as well as at the June 10, 1993 RW AC meeting and in the feedback from the Critical Choices consultation.

Public understanding of drinking water quality is very closely related to how the water looks and tastes as indicated from the telephone inquiry information. An increase in the taste or smell of chlorinated water leads most of the public to the conclusion the water is decreasing in qUality.

Taxes and Perceived Value for Taxes

Results from the Critical Choices Consultation (approximately 2,000 persons) show that 73.9 percent of the participants are prepared to pay at

A-41

About 55% of the population are willing to pay between $50 and $200 per year to reduce the levels of turbidity.

Attitude survey indicates public does not support chloramination as the secondary dis-infection option.

Written response shows strong opposition to chloramine.


least $17 per $100,000 assessed residential property value (the current average level of taxes for water). Fifty-one percent of participants are prepared to pay at least $24/$100,000 of assessed residential property value.

Attitude survey respondents were asked how much more per year they would be willing to pay for drinking water in order to decrease the cloudiness, which can reduce the effectiveness of the disinfectant used to keep water quality high. About 55% of the survey respondents would be willing to pay at least $50 more per year with some willing to pay up to $200 more per year.

Results from the attitude research show that 85% of residents rate receiving moderate to high value for the taxes they pay for their water.

DWQIP - Secondary Disinfection

Results from the Critical Choices Consultation show that when asked to consider only the health and environmental impacts 32.6% of participants prefer rechlorination and 29.1% of participants prefer chloramine. A significant number said that they did not know (15.2%) or prefer some other solution (23.1 %). Results from the Critical Choices Consultation show that when asked to consider costs and all other factors 32.6% selected chloramine and 32.6% selected rechlorination. A significant 34.8% said they "do not know" or preferred another option.

In the February 1993 attitude research (random telephone survey), when asked to consider only the health and environment risks, participants preferred rechlorination (42%) over chloramination (27%) with 26% saying neither. In general, when asked to include costs there was still a preference for rechlorination (37%) over chloramination (33%) with 25% of the respondents saying they did not like either option. In the December 1992 focus group research there was a slight preference for rechlorination.

When asked to indicate a preference, the Regional Water Advisory Committee could not agree on an option. Most members of the Committee want more information before making a recommendation. However, if the 13 members of the Advisory Committee present on June 22, 1993 were forced to choose, 7 members said they preferred chloramine and 4 said they preferred rechlorination. Two members said they preferred a water distribution system that allows for using rechlorination in more environmentally sensitive areas and chloramine in less sensitive areas.

Written responses show strong opposition to the use of chloramine. Most of these responses were through form letters and petitions. In general,

A-42

-

-Regional Water Advisory Com-mittee supports full implementa-tion of the DWQIP immediately.


when asked to select between the two, the community is divided with approximately one third saying chloramination, just over one third saying rechlorination and the last third saying they do not know or want some other choice. The consultation program to date indicates that people would like more information before a choice is made between chloramination or rechlorination as a secondary disinfectant.

DWQIP - Predesign and Planning Studies

The Water and Construction Department released the Predesign and Planning Studies for the Drinking Water Quality Improvement Plan in August 1993. The report was provided to the Regional Water Advisory Committee in late August 1993. The Regional Water Advisory Committee met on September 22, 1993 to discuss the Predesign and Planning Studies. SCBV Consultants, the firm responsible for the study, provided a presentation on the report at this meeting and the Advisory Committee discussed the report. The Advisory Committee did not come to any conclusions on the issue as information critical to their discussion of the study was not yet available. This missing information includes the regional health officer's position regarding the GVRD's need to meet federal guidelines for water quality; the position of the Ministry of Environment, Lands and Parks on the use of chloramine; the Fergus Creek Report (recovery of Fergus Creek from a chloramine spill); and storm sewer sampling results from the chloraminated and rechlorinated areas of Surrey.

The Advisory Committee met to discuss this report on November 24, 1993. The committee discussed the implementation schedule of the DWQIP. Seven of the eleven present favoured immediate full implementation of the three phased plan (including filtration of Seymour and Capilano sources), one favoured proceeding to Phase 2 (Filtration of Seymour source immediately) and three members favoured proceeding with only Phase 1 (non-filtration) at this time.

Although not asked to specifically comment on the DWQIP, during the Creating Our Future: Critical Choices consultation, one of the more frequent comments was that participants supported filtering at source, as well as comments that more information on the options for this program was needed for people to be able to decide about this program.

Seymour Demonstration Forest (SDF)

The proposed site for water treatment facilities for Seymour DWQIP Phase 1 and Seymour and Capilano DWQIP Phases 2 and 3 is the south end of the Seymour Demonstration Forest (SDF). GVRD staff have met

A-43


with the SDP Technical Subcommittee and t Committee to discuss the use of this area for w

he full SDP Advisory ater treatment facilities.

oposed area as impact on s the proposal to dispose tated this could be done

Overall there was no objection to the use of the pr the SDP is minimal. The only concern raised wa of water treatment sludges in the area and it was s in an environmentally responsible manner.

Presentations and Workshops

Exhibit A-9 Workshops and Presentations

Groups InvitedlParticipating or Requesting Topic Date

Municipal Councilors and staff DWQIPIEIA May 1992

Municipal staff, MHOs, DFO, MOE, EC DWQIPIEIA September 1992

AQUA 1992 Conference DWQIPIEIA September 1992

Regional Water Advisory Committee (RWAC) DWQIP November 1992

Regional Water Advisory Committee (RWAC) EIA Stage I December 1993 January 1993

Municipal staff, MHOs, DFO, MOE, ECl Stage lElA January 1993

Regional Water Advisory Committee (RWAC) DWQIP/DBP February 4, 1993

City of Burnaby Environment and Waste DWQIPIEIA February 9,1993 Management Committee

Canadian Journalism Foundation DWQIPIEIA March 23,1993

Salmon Enhancement Task Group DWQIPIEIA May 29,1993

Municipal staff, MHOs, DFO, MOE, ECl Stage II EIA June 1993

Municipal staff and MHOs DWQIP Predesign June 1993 and Planning

Studies

Regional Water Advisory Committee (RWAC) EIA Stage Ii June 1993 (2 meetings)

City of Coquitlam Environment Committee DWQIPIEIA June 10, 1993

Regional Water Advisory Committee (RWAC) DWQIP Predesign September 1993 and Planning

Studies

Vancouver Angling and Game Association DWQIPIEIA September 7, 1993

North Shore Fish and Game DWQIPIEIA September 22, 1993

Corporation of Delta Environment Committee DWQIPIEIA October 20, 1993

Municipal staff of Port Moody, Port Coquitlam DWQIPIEIA October 1993 and Coquitlam

SurreylRichmond Golden Rods and Reels DWQIPIEIA November 18, 1993 Clubs

Exhibit A-9 summarizes the number of the workshops and/or presentations held with government agencies, municipalities, RW AC, and nongovernment organizations regarding the DWQIP and EIA.

The general consensus from the two fish and game clubs noted in Exhibit A-9 was that they objected to the use of chloramine and favoured rechlorination with filtration. When asked what they were willing to pay, members of the two fish and game clubs (approximately 50 people each) said $100 per household for the DWQIP was reasonable as long as chloramine was not used. When told that rechlorination would in-

1. Medical Health Officers (MHOs), Department of Fisheries and Oceans (DFO), Ministry crease the cost of the of Environment (MOE), Environmental Canada (EC). DWQIP to $175 per

household per year I there was overall agreement that this was the right thing to do.

A-44

The public wants more information on DWQIP before a decision is made.


Future Public Consultation

Generally, the public lacks information on the need for the DWQIP and on the options within the plan. It is the intention of the department to provide more information to the public in early 1994 and to conduct a series of forums and a public attitude survey to discern public attitudes to the DWQIP. As well, the Regional Water Advisory Committee (RWAC) will be discussing this issue and providing further input to the Water Committee.

A-45

1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1

~ 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1


ATTACHMENT II

Disinfection Practices in Selected Cities and Countries

Primary Disinfectant Secondary Disinfectant Canada 0::\ CI02 NH2CI Cl2 CI02 NH2CI CI,

Brantford X X (1960s) Calq;ary X X Edmonton X X X (1940s) Montreal X (1978) X (1918) X (1918) Ottawa X X (1992) Toronto (City) X X Toronto (Metro) X X (1972) Victoria* X X (1940s) D.A.R.D.* X X (1992)

United States Ann Arbor X X Boston* X X (1940s) Chicago X X Denver X X (1917) Des Moines X X Hackensack X X (1982) Los Angeles (City) X (1987) X Los Angeles (Metro) X X (1985) Miami X X (1981) New York* X X Philadelphia X X (1960s) Portland* X X (1920s) San Diego X X (1982) San Francisco X X X (1981) X Seattle ** X X (1970s) Tampa X X (1982)

Germany Dusseldorf X X Frankfurt X Koeln X Wiesbaden X X - Other Countries Australia X X X Denmark X X X France X X X X X X Hungary X X X Italy X X X X Netherlands X X X X Switzerland X X X X United Kingdom X X X X X X

1. All Cities filtered unless denoted by *. 2. ** Tolt River supply to be filtered by 1998. 3. Informationfor other countries extracted from Black & Veatch survey report (October 1992). 4. 0 3 (Ozone), CI02 (Chlorine Dioxide), NHzCI (Chloramine), Clz (Chlorine). 5. D.A.R.D. (Dewdney-Alouette Regional District). 6. Disinfectant implementation dates shown in parenthesis.

A-46


Attachment III

Letters from Metropolitan Board of Health of Greater Vancouver and the Department of Fisheries and Oceans

A-47

MET'ROPOUTAN BCARO OF HEAL.TM OFGREA~COUVER

V Mr. Ben Marr Commissioner Greater Vancouver Water District 4330 Kingsway Burnaby, B.C. V5H 4Ga

Dear Mr. Marr:

ADMINISTRATIVE OFFICES . 1060 W. 8th AVE.

VANCOUVER. B.C. V6H 1C4

TELEPHONE 736·2033

November 16, 1993

Re: Drinking Water Quality lmpro'iement Plan - Chlorination versus;'Chloramlnation

The Metropolitan Board of Health (Burnaby, North Shore, Richmond and Vancouver) and the Fraser Valley (Boundary, Simon Fraser, Central Fraser and Upper Fraser Valley Health Units) Medical Health Officers met on October 13th to clarify our position on chlorination versus chloramination. As you know, our position all along had been that both secondary disinfectants will achieve public health drinking water quality objectives. The ultimate aim is to achieve a diSinfectant residual at the ends of the lines and to have a good product which is acceptable to the public. In the fIVe year secondary disinfection comparison program in Surrey, chloramination has consistently provided a residual to the ends of the lines while rechlorination has not and will require more effort by the municipalities to do so.

A new concern added to the debate is the level of disinfection byproducts, particularly Trihalomethanes (THM). Health and Welfare Canada classify THM as a probable human carcinogen and plan to lower the maximum allowable amounts of THM in Canadian Drinking Water from the current 350 ppb to 100 ppb. It is likely that rechlorination would just meet this new standard in most locations. Chloramination would meet a 50 ppb standard that is unlikely to be introduced at this time, but could be the new level in the future.

If the 50 ppb THM standard is eventually selected, rechlorination will require filtration at all watersheds. Chloramination secondary disinfection of unfiltered water will meet this possible future standard, and filtration needs at Capilano and Seymour to reduce ~riodic turbidity could be delayed some time to overcome the immediate cost impact.

Chloraminated water has significantly less (almost no) chlorinous taste and odour than does rechlorinated water. If the public does not like the taste and odour of the water, they will seek out alternate sources which will defeat one of the major aims of our distribution program, Le. good tasting water.

Since chloramination appears to give the best tasting water, will adequately provide good diSinfection, will meet the new 100 ppb THM (and would meet a 50 ppb THM) and will delay or reduce the need for filtration, the Medical Health Officers unanimously support chloramination as the future secondary disinfection process for the GVRD.

Yours sincerely,

~~~~~~:-~~~~~,~.~~>~; .;John Blatherwick (Vancouver)

r. John Garry (Richmond) Dr. Arlene King (Burnaby) Dr. Brian O'Connor (North Shore)

Dr. Lorna Medd (Boundary) Dr. Bill Meekison (Simon Fraser) Dr. Roland Guasparini (Central Fraser Valley)

1+1 FISheries and Oceans

Pacific: Region Suite 400 - 55S West Hastings St. Vanc:c>IJIIef'. B.C. V6S5G3

!o~ - 6 1993

Peches etOceans

Region du PacifiQue Piece 400 - 555 rue Hastings ouest Vanc:.oI.Ner (C.-B.) Ve85G3

7430-1

- •. - "'-:r • , F' 1 ; , . ' .. ',-: .J !~ "'11:.3 'J" ; -

: CR1::;~~AL .. _!;;;: ::..~ .. ___ ._._ ACT1C OIl .............. _ .. _ .. _ .... __ .. __ ._._

Mr. B. Marr, Commissioner Greater Vancouver Wata District 4330 IGngsway

, ....... " ................. I

Burnaby, B.C. V5H4G8

Dear Mr. :Mart:

STAGE II EIA OF PROPOSED SECONDARY DJSlNFECTION AL~ FOR DRINKING WAlp.

1bis is in response to your letter of June 25, 1993 which referenced' an earlier request made by the Department pursuant to Section 37 of the Fisheries Act.

As I indicated in my letter of Jurie 14, 1993, the District is still required to satisfy the DFO regulatory requirements outlined in our Section 37 (1) request of April 24, 1991. The ETA and public review process which have been adopted by the GVWD have not yet satisfied this requirement. The Stage II document which is an overview of the various d.rin.king water disinfec;tion options, does not constitute a reSponse to our Section 37 request as it does not present a proposal for a specific work or undertaking. \Vhile I understand that Stage ill will represent such a proposal DFO wishes to advise you at this time ( based on information provided in the Stage n ) that we have serious reservations concerning the use of chloramine. Specifically the mitigative measures identified in Stage n to prevent chloramine impacts to fish and fish habitat are considered inadequate. I also wish to reemphasize that compensation to offset anticipated impacts to fish and fish habitat from chloramine or other chemical releases is unacceptable.

Canada

,

-2-

DFO will await the Stage m report before developing a regulatory position pursuant to Section 37 (1). Notwithstanding, in my view the Board. and member municipalities should be made aware of the Department's outStanding· concerns with regard to chloramines.

Yours sincerely,

P.S.Cbamut Director-General Pacific Region

cc: D. Bevan D. Deans J. Clark C.Fraser E. Anthony J • McCracken D. Paterson

-

Appendix B Future Water Supply Table of Contents

Appendix B - Future Water Supply

Section 1.0 - Purpose .................................................................. 8-1

Section 2.0 - Study Overview ...................................................... 8-2

Section 3.0 - Present Supply Facilities ........................................ 8-3

Section 4.0 - Hydrology of Existing Sources ............................... 8-8

Section 5.0 - Regional Water Demand ...................................... 8-11

Section 6.0 - Future Supply Sources ......................................... 8-14

Section 7.0 - Alternative Regional Plans ................................... 8-20

Section 8.0 - Conclusions .......................................................... 8-29

Appendix B Future Water Supply List of Exhibits


Exhibit 8-1 Greater Vancouver Water Supply Sources and Systems ............................................ 8-4

Exhibit 8-2 GVRD Source Water Storage Capacity ................. 8-5

Exhibit 8-3 GVRD Water Supply System Normal Operations ............................................................. 8-6

Exhibit 8-4 Population Support Capacity ................................. 8-9

Exhibit 8-5 Watershed Supply ................................................ 8-10

Exhibit 8-6 GVRD Water Consumption Projections ............... 8-12

Exhibit 8-7 Supply Status ....................................................... 8-13

Exhibit 8-8 Alternative Supply Sources .................................. 8-15

Exhibit 8-9 Economic Comparison of Project Alternatives .......................................................... 8-18

Exhibit 8-10 GVRD - Source and Seymour Dam Seismic Decision Tree ......................................... 8-23

Exhibit 8-11 GVRD Water Supply Alternatives ........................ 8-24

Exhibit 8-12 Project Costs for Supply Options ......................... 8-26

Exhibit 8-13 Net Present Value of Options .............................. 8-28

Exhibit 8-14 Summary Comparison of Options ........................ 8-28

Exhibit 8-15 Water Treatment Options ..................................... 8-31

- Purpose is to summarize re-sults of on-going Com-prehensive Regional Water Supply Study.

Section 1.0 Purpose


This Appendix summarizes the principal information and findings resulting from a Comprehensive Regional Water Supply Study being conducted by the Greater Vancouver Regional District (GVRD).

Among many functions, the GVRD is responsible for providing wholesale water service to most of the cities and municipalities of the Greater Vancouver area In the past, planning and management needs were addressed through development of progressive five-year capital improvement programs.

In 1990, the GVRD identified a need to develop a more comprehensive plan for assuring the region a high quality supply meeting demands for the next 50 years. A study with this objective is in progress. The study has progressed to the point where significant policy issues are identified. These issues are being addressed in a coordinated way by the GVRD as described in the Summary Report. Once these policy decisions are made, the Comprehensive Regional Water Supply Study will be completed and an appropriate capital improvement plan will be prepared.

B-1

Two review groups pro-vided technical oversight to the Comprehensive Regional Water Supply Study.

Section 2.0 Study Overview


Two committees have participated in the study and provided technical advice and guidance. These committees are described below.

2.1 Municipal Technical Committee

This Committee was formed shortly after the study commenced. It is composed of representatives of the engineering departments of the municipalities served with water supplied by the GVRD. The Committee has met throughout the study to review and comment on discussion papers prepared by the GVRD and its consultants.

2.2 Review Panel

A Panel of three individuals from outside the GVRD membership was created to perform an independent review. Each individual was recognized for professional experience and expertise in municipal water supply planning. This Panel provided independent review and critique of the methodology, criteria, and results of key aspects of the study.

B-2

The Greater Vancouver regional water supply system dates to 1886 and presently serves about 1.6 million people.

Wholesale water is supplied to 18 jurisdictions.

Water is obtain-ed from three watersheds managedfor drinking water supply: Capi-lano, Seymour, and Coquitlam.


Section 3.0 Present Supply Facilities

3.1 Development History

The origin of the regional water system serving the Greater Vancouver area dates back to 1886. In that year, the Vancouver Waterworks Company began development of the CapUano River as the source of supply for the newly incorporated City of Vancouver. By Act of the Provincial Government in 1926, the Greater Vancouver Water District (GVWD) was created. Since that time, the GVWD has developed a network of mountain lakes, dams, reservoirs, pump stations, and supply mains which now serve potable water to about 1.6 million people. With the formation of GVRD in 1971, the GVWD became part of that larger organization for administrative purposes, although remaining a separate legal entity.

The GVRD presently provides a reliable source of supply on a wholesale basis to nearly all of the municipalities and cities in the Greater Vancouver area. This service area is shown in Exhibit B-1. Membership in the GVWD has gradually grown through the years from the charter member of the City of Vancouver in 1926 to entry of the newest member, City of Langley, in 1991. Water service is currently provided to sixteen members and two non-members (University Endowment Lands and Point Roberts).

3.2 Primary Facilities

Water supply is obtained from three river sources: Capilano, Seymour, and Coquitlam as shown in Exhibit B-1 on the following page. Dams and reservoirs exist at each supply point. Since the watersheds above the supply points are managed and protected, only screening and chlorination has taken place at the source intakes.

Storage within each watershed is a major component of supply during the summer months. Storage data and the relative contribution of each watershed to total water use are presented in Exhibit B-2 on page B-S.

B-3

ST1IA1T OF G80RGlA

BOUN1JAKT ~y

CANADA USA

Exhibit B-1 Greater Vancouver

Water Supply Sources And Systems

B-4


LEGEND ~ WAlCRSHED

....---..... COAS11JNE. LAKES ". STREAMS

MUNICIPAl. BOUNDARY

GoY.W.O. WATERMAIN


Exhibit 8-2 GVRD Source Water Storage Capacity

The supply system for the region is schematically shown in Exhibit B-3. This system consists of twenty reservoirs and tanks, fourteen pumping stations, over 500 kilometres (310 miles) of supply mains, three primary chlorination treatment stations, six pressure regulating sites, and 113 metering stations. The entire system is managed and controlled from a central operations centre that is continuously staffed.

Available Storage Capacity

Top Water Annual Elevation Use (%) in Metres Megalitres Acre-Feet

Capilano Lake 40 146 56,770 46,000

Seymour Lake 45 213* 25,280 20,450

Coquitlam Lake 15 155 241,910 196,000

Burwell Lake 838 15,090 12,600

Palisade Lake 887 19,500 15,800

Loch Lomond 1,017 7,040 5,700

* Installation of stoplogs on a seasonal basis raises the elevation by 1.8 m; increasing the available storage by 5,590 megalitres (4,550 acre-feet).

Provincial water licenses exist for current use ofCapilano and Seymour; conditional licenses auth-orize increased storage at Seymour.

3.3 Water Licenses

Under laws of the Province of British Columbia (Water Act, RS Chapter 429), water is a Crown-owned resource. Authorization to use surface water is obtained through application to and issuance of a license by the Ministry of Environment, Lands and Parks, and Water Management Division.

The Water Act provides that licenses may be issued for uses of water considered to be beneficiaL Among the several purposes identified are:

o

o

Waterworks - the carriage or supply of water by a municipality, improvement district, utility, or person for the use of the residents of a locality; and

Storage - the collection and impounding of water; normally the stored water is used to support a diversion license.

The GVWD holds diversion and storage licenses for current use of the Capilano and Seymour watersheds. In addition, conditional storage licenses exist for future development of about 123,340 megalitres (100,000 acre-feet) of water in the Seymour watershed. These licenses were secured in anticipation of eventually raising the existing Seymour Falls Dam.

B-5

t@ TANK

CAPILANO

CAPILANO LAKE

ClEVEtAND DAM PUMPHQUSE

MAlHERS AVE ( ______ ~ MAIN

MAHON PUMP STA.

SASAMAT PUMP STA.

1st NARROWS CROSSING

KERSLAND RESERVOIR

OAJ( STREET BRIDGE CROSSING

DrAS ISLAND CROSSING

FERRY AD PUMP STA.

'-../ TO

PT. ROBERTS U.S.A.

) GREENWOOO PARK

RESERVOIR

VANCOUVER HTS. RESERVOIR

UntE MTN PUMP STA.

PEBBLE HILL BOOSTER PUMP

SEYMOUR

SEYMOUR LAKE

SEYMOUR CHLORINA nON

PLANT

BEACH YARD PRESSURE

REDUONG STA.

HELUNGS TANK

2nd NARROWS CROSSING

aENTRAL PARK RESERYOIR

LOCH LOMOND

aENTRAL PARK PUMP STA.

ANNACIS ISLAND CROSSING

) NORTH DELTA PUMP STA.

.... _--{f-:.J--..... _)

BURNABY MTN PUMP STA.

WESTBURNCO PUMP STA.

KENNEDY PARK RESERVOIR

...-----

COQUITLAM LAKE

COQUITLAM CHLORINA nON

PLANT

~MOODY~S~~--------~ L -i.FUTURE...L -Y'

CAPE HORN RESERVOIR

CAPE HORN PUMP STA.

MAPLE RIDGE PUMP STA.


MAPLE RIDGE RESERVOIR

BARfISTON ISlAND CROSSING

\./'- PORT MANN

WHALLEY RESERVOIR

........ ~ ...... ~ CROSSING

B-6

CLAYTON RESERVOIR

I I I I I __________ .L ___ .J

( FUTURE )

Exhibit B-3 Greater Vancouver Regional District

Water Supply System Normal Operations

Roth R.C. Hydro and the GVWDhoid water licenses for use of Coquitlam; terms of joint use are set forth by Agreement.

Approximately $15 million of remedial work is required on Seymour Falls Dam to meet current earthquake standards.


At Coquitlam, licenses are held by the GVWD dating to 1886 and 1903 for use of 227 Megalitres per day (ML/day). The British Columbia Hydro and Power Authority (B.C. Hydro) owns Coquitlam Dam and holds licenses for power generation for the remaining watershed waters. These waters are diverted at Coquitlam Lake to Buntzen Lake and then to the power plant on Indian Arm. However, by terms of a 1988 Agreement between the GVWD and B.c. Hydro, the GVWD is to:

o Continue to use up to a maximum of 227 ML/day as authorized by license;

o Utilize up to a maximum annual average of 682 ML/day and a peak of 1,182 ML/day, including the 227 ML/day permitted by license;

o Reimburse B.C. Hydro for use of water in excess of 227 ML/day under a schedule defined in the Agreement as "Long Run Marginal Cost." The 1991 rate of payment under this schedule was $0.049 per kilowatt hour, which is equivalent to $13 per Megalitre; and

o Should waters from adjoining watersheds (Widgeon Lake, Or Creek, Hixon Creek) be diverted by the GVWD into the Coquitlam watershed, the diverted waters may be used by the GVWD with no payment to B.C. Hydro.

3.4 Dam Safety

In compliance with requirements of the Dam Safety Branch of the Ministry of Environment, Water Management Branch, safety inspections were recently conducted by the GVRD of its water storage dams. Structural deficiencies under current earthquake standards were found at Capilano and Seymour Falls dams. At Capilano, the necessary improvements have been made together with modifications necessary to safely pass the maximum design flood flow. However, at Seymour Falls Dam, improvements will cost about $15 million. Since additional supply can be developed by either raising the existing dam or replacing it with a higher structure, remedial construction is being deferred pending a decision by the GVRD on new source of supply development. A more detailed discussion of the dam safety/seismic considerations is presented in Appendix C (Seymour Falls Dam Safety).

B-7

Computer sim-ulation studies of streamflow and storage were conducted to determine the number of peo-ple that can be served from the three developed watersheds.


Section 4.0 Hydrology of Existing Sources

4.1 Water Supply Analysis

In response to low water/drought conditions experienced in recent years, the GVRD commissioned a series of hydrologic studies of the Capilano, Seymour, and Coquitlam watersheds.

The objective of these studies was to determine the population that can be served (Population Support Capacity) from each of the three watersheds under a range of predicted flow conditions/reoccurrence intervals and given the following circumstances:

o Existing facilities with removal of all hydraulic constraints which limit flow;

o Optimum use of watersheds by developing additional storage and transmission facilities; and

o Diversion of waters of Widgeon Lake, Or Creek, and Hixon Creek to Coquitlam Lake.

The Population Support Capacity (PSC) for each of these conditions was determined by:

o Analysis and synthesis of streamflow records for the period 1914 through 1992;

o Use of a variable monthly average day per capita demand requirement based on historical data. This data represents an annual average water consumption of 808 litres per capita per day (Lpcd);

o Assuming fish flow bypasses are required at Capilano and Seymour Falls dams;

o Considering return intervals of 100-, 50-, 10-, and 2-years; and

o Model simulation of streamflow and water demand data.

B-8

lation Support city was devel-based on a 50-

Popu Capa oped year return period.


4.2 Population Support Capac it y

Results of the watershed analysis are shown in E xhibit B-4. Since the riterion of 98 percent ers are reported.

GVRD has adopted a water supply planning c reliability (50-year return interval), only these numb

Exhibit 8-4 Population Support Capacity

(50-year Return Period)

Operating Condition Capilano Seymour Coquitlam Total

Three conditions should be noted with respect to Population Support Capacity (PSC). First, the hydrology analysis determined that the Capilano watershed has potential for serving 1.6 million people if 201,000 megalitres (163,000 acre-feet) of storage is provided (compared to

Existing Development 670,000 565,000 730,000 1,965,000 (without hydraulic con-straints and per 1988 Coquitlam Agreement)

With Seymour 237 m Dam 670,000 1,250,000 730,000 2,650,000

Existing with Coquitlam 670,000 565,000 830,000 2,065,000 Tributaries

Optimum Development of 670,000 1,250,000 1,900,000 3,820,000 Three Watersheds

Optimum de-velopment of three water-sheds would serve 3.82 million people.

Significant de-velopment po-tential exists in Seymour and Coquitlam watersheds.

current 56,700 megalitres or 46,000 acre-feet). Since a reservoir site with this potential has not been identified, the present development is considered optimum for purposes of this study. Second, by raising the existing or building a new Seymour Falls Dam to water surface elevation 237 m, use of the Seymour River watershed would be optimized. The Seymour Falls dam site will accommodate a dam to elevation 237 m. Third, to fully utilize the waters of the three small streamsllakes to be diverted into Coquitlam Lake, the Lake must have a storage capacity of 296,000 megalitres (240,000 acre feet) (as compared to current 241,750 megalitres or 196,000 acre-feet). Without raising Coquitlam Dam the three streams provide only a small increase in PSc.

4.3 Yield of Watersheds

For purposes of this study, the PSC numbers were converted to watershed yield as expressed in ML/day. The conversion was based on:

o

o

The annual average supply equaling the PSC multiplied by 808 Lpcd, and

A peak day to annual average day demand ratio of 2.0 to 1.0.

B-9


Under the converAverage Flow (MLlday)

1,600 ,------------------------sion, the average day supply status is graphically shown in Exhibit B-S. The current and optimum yields for Capilano are shown as the same since a dam site . for increased storage has not been identified. The Coquitlam optimum yield does not include the inter-basin transfer of

1,455

1,400 0 Current Development

&ill Current Yield

1,200 mlIIl Optimum Yield

1,000

800

600

400

200

o L--..l--_

Capilano Seymour Coquitlam

Exhibit 8-S. Watershed Supply

the three small streams/lakes. As may be noted, the potential for future development of the

Seymour and Coquitlam watersheds is significant. However, the Coquitlam option will require a new agreement with B.C. Hydro that could include buy-out of the rights and interests in the Buntzen Hydroelectric Project.

B-lO

Future popula-tion and water consumption were forecast.

Population increase of 1.2 million people projected in next 50 years.

Three alterna-tive water de-mand forecasts were made with progressive in-creased empha-sis on water conservation.


Section 5.0 Regional Water Demand

5.1 Forecast Approach

Two tasks were completed to forecast regional water demands through the year 2041: the first was to predict population growth, and the second to forecast per capita water consumption. The product of each was then combined for a forecast of the future water requirements for the region.

Both tasks examined each member entity of the GVWD individually. Individual forecasts were required for hydraulic modeling of the regional system. However, for purposes of this report, demand forecast results are reported only at the regional level.

5.2 Population Projections

Using standard techniques which consider aging of the population, and fertility, mortality, and migration rates, the Strategic Planning Department of the GVRD forecasted the population growth for the region through the year 2041. In reporting its results, Strategic Planning emphasized that its normal forecast period does not exceed 25 years and the confidence level was high only through the year 2026. With this qualification, the population forecast for the GVWD service area is summarized as follows:

Year

1991 2001 2011 2026 2041

5.3 Water Requirements

5.3.1. Forecast A

Population

1,557,900 1,861,569 2,133,933 2,507,559 2,776,260

A statistical method called regression analysis was used to predict future per capita consumption. A linear model using data from 1980 to 1990, with a trend factor, annual cooling degree days, and summer precipitation as variables was found to be the most appropriate. This analysis forecast a gradual and continued increase over time from 737 Lpcd in 1991 to 1,024 Lpcd in 2041. This yields an average annual increase in per capita

B-ll

ForecastB (moderate conservation) was selected.


consumption of about 0.7 percent. Similar forecasts were made for peak day and peak hour per capita requirements.

The analysis described above did not consider the effects of water conservation on trends in per capita consumption. Based upon experience during the summers of 1992 and 1993, when outdoor water use was curtailed, Forecast A analysis was considered to produce a high forecast. Two alternative forecasts were developed which placed emphasis on future water conservation (Exhibit B-6). Assumptions in these forecasts are discussed below.

5.3.2 Forecast B

Forecast B assumes that recent water conservation efforts will continue and be expanded in the future and that the public will gradually become

Annual Average Consumption (MUday)

more supportive of reduced water use. It further assumes that the rate of regional per capita consumption growth will gradually decline and consumption will stabilize at about the current level of the City of Van-

3,000 ,.-----------------------------,

2,500

2,000

1,500

1,000

500

Current Yield of Capilano, Seymour _ andCoquitl~Watersheds __ ~=~

Regional Supply Deficit

@ Trend Projection

® Base Water Conservation

© Vigorous Water Conservation

1966 1971 1976 1981 1986 1991 1996 2001 2006 2011 2016 2021 2026 2031 2036 2041

Year

Exhibit B-6. GVRD Water Consumption PrOjections

5.3.3 Forecast C

couver (808 Lpcd). By the year 2041, the projected use is an estimated 20 percent below Fore-cast A.

Forecast C assumes that a very aggressive conservation program will be implemented with substantial costs incurred. There will be metering of all residential connections. By the year 2041, a further reduction of at least 10 percent will be achieved below Forecast B.

B-12

5.4 Supply Status

Exhibit B-7 Supply Status

Supply (ML/day)

Source Current* Optimum

Capilano 540 540

Seymour 459 1,014

Coquitlam 590 1,455

Total 1,589 3,009

Year 2041 Demand

2,245


Based upon results of the watershed analysis and demand forecast, the supply status is summarized as shown in Exhibit B-7 (all numbers are average daily flow in megalitres):

From this analysis, it is concluded that:

* With removal of hydraulic constraints.

Further devel-opment of the Seymour water-shed and/or Coquitlam watershed will meet year 2041 demands.

o

o

o

Current development is inadequate to fully meet current needs under drought conditions.

With improvements to the existing transmission facilities, current yield will carry the region to the year 2005. The next increment of supply must be on line by that year.

Either 1) full use of Coquitlam or 2) construction of a higher Seymour Falls Dam along with a modest increase in use of Coquitlam will meet regional demands for the next 50 years.

B-13

Criteria were adopted to guide the selec-tiono/new supply sources to be evaluated.

One option is to expand use 0/ existing sources.


Section 6.0 Future Supply Sources

6.1 Screening Criteria

The demand forecast identified a supply deficiency of approximately 655 ML/day (average) for the 50 year planning period. To meet this need, supply alternatives were examined in three general categories: 1) expanded use of existing sources, 2) development of new surface water sources, and 3) groundwater development.

A number of planning criteria were adopted to guide the selection of sources to be evaluated. These criteria are summarized as follows:

o Water Quantity. The quantity of water available should be significant from a regional standpoint.

o Water Quality. Give preference to those sources requiring the least extensive treatment.

o Efficiency. Make full use of the eXIstmg supply system and develop new sources most complementary to this system.

o Reliability. Select sources with the highest potential for operation during failure of other system sources and/or facilities.

6.2 Sources Evaluated

By applying the above criteria to sources local to the planning area, seven primary sources were selected for evaluation as shown in Exhibit B-8 and listed below.

6.2.1 Existing Sources

o Capilano - Remove hydraulic constraints in transmission facilities.

o Seymour - Repair Seymour Falls Dam and remove hydraulic constraints; or, construct a new and higher replacement dam.

o Coquitlam - Remove hydraulic constraints in transmission facilities and fully utilize supply within limits of 1988 Agreement; or, acquire all ofB.C. Hydro's interests in the Coquitlam watershed

B-I4

LOCH LOMOND

BURWELL LAKE

PAUSADE LAKE

« (3 0:: o W o k o


SEYMOUR LAKE

COQUITLAM LAKE

I GROUND WATER I 1

Exhibit B-8 Alternative Supply Sources

B-15

BRITISH COLUMBIA WASHINGTON

Another option is to develop new surface or groundwater sources.

Technical criteria were established to assure uniform comparison of alternative supply sources.


and fully utilize the source; and/or, divert three streams/lakes in adjoining watersheds to Coquitlam Lake and utilize the transferred waters.

6.2.2 New Sources

o

o

o

Pitt LakelPitt River - Pump and filter the waters of Pitt Lake or Pitt River as an alternative to full development of Coquitlam Lake.

Fraser River - Pump and filter the waters of the Fraser River as an alternative to building a new Seymour Falls Dam.

Groundwater - Construct wells in the Fraser Lowland and pump groundwater into the regional transmission system.

A number of development options exist for enlargement of the existing sources depending upon water transmission (pumping or gravity flow) and decisions regarding filtration. In all, 29 alternative development options for the seven sources were examined in detail.

6.3 Technical Criteria

The objective of the evaluation was to develop and compare capital construction and operation and maintenance (O&M) costs per unit of water (megalitres/day) for each supply option. The evaluation was to result in a selection of the most cost effective options for further analysis. To assure uniformity in comparison, a number of technical criteria were adopted. These included:

o

o

o

Unit cost values were developed for transIlliSSlOn pipelines, pumping plants, and treatment/filtration facilities.

Supply from a source was to meet the standard of 98 percent reliability (shortage occurring only once every 50 years).

The peak day to average day flow factor is 2.0 to 1.0.

o Transmission pipeline capacity shall be designed for peak day flow.

o Water filtration plant design capacity shall be based on peak day flow.

o For alternatives which assume GYRD will acquire full interest in Coquitlam waters, payment to B.c. Hydro is included for two accounts, as identified by B.C. Hydro, as follows:

B-16

TheGVRD hydraulic model was used in the analysis of new sources of supply.


• Long-term loss of energy at the long-run marginal cost as per the 1988 Agreement. At the 1991 rate of $13 per megalitre, this payment is calculated as $13 x 1,227 MLiday x 365 days = $5,820,000 per year.

• Loss of capacity at the long-run marginal cost. This payment is calculated as $40,000/MW/yr x 73 MW = $2,920,000 per year.

Revenue benefits were also considered based upon:

o Sale of firm and non-firm power generated by water available in excess of regional water supply demands.

o An offset for power presently purchased from B.c. Hydro by the GVWD.

6.4 Modeling of Regional System

An existing model of the regional system had been developed on the GVRD computer system during the 1980' s. The WATER hydraulic analysis software is used. After detailed comparison with the merits of other software, the existing model was retained and updated to reflect current regional system conditions. Full calibration then took place to assure the model reflected actual field conditions. Information from the calibrated model was used to analyze the hydraulic conditions of each source option and to determine transmission pipeline and pumping requirements.

6.5 Results of Evaluation

The total project cost of each supply option was determined and reported as a real levelized unit cost as expressed in million dollars per ML/day of water produced. This analysis did not result in a ranking of supply sources, but it did provide an economic comparison of the options for water supply on a unit cost basis. These unit costs are graphically shown in Exhibit B-9. Groundwater is not shown since it was concluded that sufficient information was not available to confirm that groundwater was a viable regional supply source.

B-17


M$lMLIday

0.120-

0.100-

0.080-

0.060-

0.040-

Pumping and Filtration

Supply Alternative

Exhibit 8-9. Economic Comparison of Project Alternatives (Real Levelized Unit Costs)

Based on the economic com-parison, the least cost alternatives are expansion of the existing supply sources.

The technical conclusions reached through this analysis are summarized as follows:

o

o

Although the watershed yield of Capilano exceeds current development, the site for a new and higher dam has not been identified. Within the current planning time frame, further development options appear to be limited to utilizing the full capability of Cleveland Dam on the Capilano source through removal of existing hydraulic constraints.

A new and higher dam could be built at the approximate site of the existing Seymour Falls Dam. Complete re-building is less costly than raising the old dam. A new dam raising the maximum water level about 23 m (to elevation 237 m) will optimize use of runoff from the watershed. The additional supply could meet the water demands of the region to about the year 2031.

o From a system operation standpoint, an alternative to expanding the Seymour supply is construction of a pumping plant and treatment works drawing water from the Fraser River. Year-round pumping and extensive treatment (granular activated carbon) of Fraser River water is required. Due to these factors, the unit cost of Fraser River water is about 1.75 times greater than the comparable cost of water from a new dam and filtration plant at Seymour Falls.

B-IS

Fraser River, Pitt River and Pitt Lake water require exten-sive and expen-sive treatment.

Adequate data is not available to assess the availability of groundwater.


o The existing Coquitlam Lake dam fully develops the runoff from the watershed. A large portion of this runoff is used by B.C. Hydro for hydropower generation at the Buntzen powerhouse. B.C. Hydro has indicated that long-term payment for lost hydropower generation and revenue will be required to transfer rights and interests in this hydropower water to the GVRD. However, the transfer would meet regional drinking water needs beyond the planning period (year 2041).

o Also from a system operation standpoint, development and use of Pitt River or Pitt Lake are alternatives to expanding use of Coquitlam Lake. Extensive filtration is required at these new sources and the availability of adequate year-round supply at Pitt Lake is questionable. In comparing unit cost of water, the Pitt River and Pitt Lake alternatives are 1.6 and 1.3 times greater, respectively, than the full use of Coquitlam if filtration of Coquitlam is provided. However, without filtration at Coquitlam, the Pitt River and Pitt Lake unit costs are 8.1 and 6.3 times greater than full use of Coquitlam.

o Unit costs for supply from a new Seymour Falls Dam (with associated filtration plant) and fully utilizing Coquitlam water (also with filtration) are essentially equal. However, Seymour unit cost with filtration is 5.2 times greater than Coquitlam without filtration.

o Development of groundwater was determined not viable at this time since sufficient information was not available to document supplies of a regional significance. A three year study initiated in 1993 by the Geological Survey of Canada will provide a better data base on groundwater of the Fraser Lowland for future consideration.

B-19

Two supply sources were se-lected for further analysis:

1. Build new and higher Seymour Falls Dam,

2. Fully utilize Coquitlam.

Must also consider:

1. Water quality requirements, and

2. Dam safety needs.


Section 7.0 Alternative Regional Plans

7.1 Future Supply Sources

Based upon the evaluation of the seven primary sources of supply described in Section 6, two supply sources were determined to be the most viable from an economic standpoint. These sources were carried forward in the study for more detailed consideration.

7.1.1 Seymour First, Followed by Coquitlam

Construct a new Seymour Falls Dam to water surface elevation 237 m. The dam would be at the approximate site of the existing dam. Since the existing dam would be replaced, it is assumed that only limited seismic repairs would be made for the interim period.

It is expected that the new and larger reservoir will result in higher turbidity levels for a number of years. For this reason, a filtration plant must be constructed simultaneously with the dam.

At about the year 2031, additional water supply is required. Increased use of Coquitlam Lake above the limits of the current (1988) Agreement with B.c. Hydro would then take place.

7.1.2 Coquitlam

Through complete buy-out or other contractual arrangements, acquire full interest in the Coquitlam watershed from B.c. Hydro. Consistent with demand, gradually reduce use of water for hydropower production and transfer use to regional water supply. Eventually phase out the Buntzen power plant.

Immediately repair Seymour Falls Dam to meet seismic standards.

7.2 Related Considerations

As noted in Section 3 (Present Supply Facilities), since the watersheds are managed and protected for public water supply, water treatment of the existing water sources has consisted of screening and chlorination. However, based on the results of increased water quality monitoring in the early 1980s, a series of water quality studies were undertaken by the

B-20

GVRDhas adopted a 3-phase Drinking Water Quality Improvement Plan.

Phase I - Non-filtration Improvements

Phase II-Filter Seymour

Phase IIIFilter Capilano


GVRD. These studies resulted in GVRD Administrative Board adoption in 1990 of a Drinking Water Quality Improvement Plan (DWQIP).

The water quality studies, DWQIP, and cost for implementation are described in detail in Appendix A (Drinking Water Quality Improvement Plan). For summary purposes, the three phases of the DWQIP are briefly described as follows:

o Phase I - Consists of four programs for immediate implementation.

o

o

• Improved primary chlorination and contact facilities would be added at all three source reservoirs.

• Secondary disinfection to control bacterial levels and to provide continuing disinfectant protection throughout the municipal systems would be achieved through the use of a chlorine ammonia compound known as chloramine added downstream from the three source treatment facilities, or rechlorination at a series of up to 60 rechlorination stations.

• A pipeline and associated pumping stations (the Westerly Transfer) would be built to transfer water from the Coquitlam reservoir into either the Seymour or Capilano distribution systems, but not both, during periods of high turbidity at the westerly sources.

• Significant corrosion of metal plumbing pipes, particularly copper, would be reduced by raising the pH and alkalinity levels through mineral additions.

Phase II - A filtration plant on Seymour would be built near Rice Lake further reducing turbidity in water distributed to municipalities in its service area.

Phase III - The Seymour filtration plant site would likely be expanded to accommodate the filtration of Capilano to further reduce turbidity in water distributed to municipalities in its service area. To accomplish this, Capilano water would be pumped through a tunnel to an expanded filtration plant at the Rice Lake site.

Since adoption of the DWQIP in 1990, two areas of concern have arisen. First, the question of whether chlorine or chloramine is used for secondary disinfection in Phase I has become extremely controversial. The decision on this question significantly impacts the structure of the regional water supply plan. Second, filtration of Coquitlam is not included in the

B-21

The regional water supply plan must address the Seymour Falls Dam safety issue.

Supply plan must consider water quality, water supply, and dam safety together.

Six supply options have been developed.


DWQIP because of its historical low turbidity and high water qUality. However, tightening of the water quality guidelines particularly with respect to disinfectant by-products, coupled with a rechlorination option for secondary disinfection could result in the need for filtering Coquitlam in the future.

In addition to water quality relationships, the regional supply plan must consider design and construction requirements related to the seismic/earthquake vulnerability of the region. This relationship is described in Appendix C (Seymour Falls Dam Safety). Of primary concern is the need to upgrade Seymour Falls Dam to bring it into conformance with modern standards. Estimated cost for upgrade is $15 million. If the dam is to be replaced in the near future, limited repairs could be made at a lesser cost, subject to the approval of the Provincial Dam Safety Branch.

7.3 Merging of Issues

Water quality improvements, selection of the next water source, and dam safety are all interrelated. Merging of these key issues is necessary to facilitate development of alternatives that provide a balance to meeting all GVRD water supply objectives.

Relationships that must be addressed are:

o Construction of a new Seymour Falls Dam will trigger filtration of this source because construction related turbidity will otherwise be unacceptable for five to ten years.

o If rechlorination is chosen as the secondary disinfectant, and future guidelines for disinfection by-products are more restrictive, filtration of all sources will likely be required.

o Comprehensive repairing of Seymour Falls Dam may not be required if Seymour is selected as the next source since anew, higher dam would be constructed in the near future.

Based on these key interrelationships, six options have been developed for further evaluation as shown in Exhibit B-lO. All options assume that at least Phase I of the DWQIP will be implemented to comply with the B.c. Health Act. Further, the two sources evaluated are expanded use of Seymour and Coquitlam. If Seymour is selected as the next source, earthquake concerns are addressed by a new dam. If Coquitlam is selected, Seymour Falls Dam will be upgraded in place.

B-22

•


,-___ -::::Ch=.:lo:::raIIU='na=te'-j Secondary Disinfection Decision Rechlorinate

'-------~ Because of the costs and health implications, drinking water quality should be the driving force in the decision process. Once decisions about secondary disinfection have been made, the next source of supply can be more readily determined.

O~~g:'c:l Seymour

Seymour Filtration

Plant

New Dam at Seymour

Falls

Ultimately Fully Utilize Coquitlam

o~~g:'c:Z Coquitlam

Upgrade Seymour Falls Dam

Fully Utilize Coquitlam

y"r Disinfectant By-Products ~NO aConcem?

t t , t O~~g:'c:3 O~~~~4 O~~g:'c:5 O~~g:'c:6 Seymour Coquitlam Seymour Coquitlam

Filter All Filter All Seymour Upgrade Seymour Sources Sources Filtration Falls Dam

Plant New Dam at Upgrade Seymour Fully Utilize

Seymour Falls Dam New Dam at Coquitlam

Falls Fully Utilize Seymour

Falls 45 -60 20-30 Coquitlam Rechlorination 30- 50 Rechlorination

Stations 20-30 Rechlorination Stations Rechlorination Stations

Ultimately Stations Fully Utilize Ultimately Coquitlam Fully Utilize

Coquitlam

Exhibit 8-10. GVRD - Source and Seymour Dam Seismic Decision Tree

Elements of plans vary depending upon choice of secondary disinfectant.

7.4 Elements of Optional Plans

Referring to Exhibit B-lO, Options I and 2 assume chloramine is used and that filtration of all sources is not needed because disinfection byproducts are less than proposed standards. Filtration is needed for control of turbidity associated with new dam construction on Seymour (Option 1). Options 3, 4,5, and 6 assume rechlorination is used and provide choices of both Coquitlam and Seymour as future sources. Options 3 and 4 are forward looking and are based on the premise that disinfectant by-products are presently, and will remain a significant issue. These options also include immediate filtration of all sources to enable GVRD to meet present and future water quality standards. Options 5 and 6 are based on the premise that disinfection by-products are not major concerns and filtration is not immediately required at Capilano and Coquitlam. This is just the opposite of Options 3 and 4.

7.5 Economic Evaluation

The overall time lines for implementation of the alternative regional supply plan options are shown in Exhibit B-11 on the following page. Significant variables within these options are the requirements for pumping and water transmission facilities and for water quality improvements. The pumping and transmission works were determined by hydraulic modeling of that portion of the regional system generally north of the Fraser River. Elements of the system that are outside this area have

B-23

3,000

2,500 ,.-...,

~

:3 62,000 "0 § 8 (l)

o 1,500

1,000

3,000

2,500 ,.-...,

~

:3 62,000 "0 § 8 (l)

o 1,500

1,000


First Source is Seymour, Followed by Coquitlam - Options 1, 3 and 5


2144

Projected Demand


1991 1996 2001 2006 2011 2016 2021 2026 2031 2036 2041 Year

First Source is Coquitlam, Followed by Seymour - Options 2, 4 and 6


Full Coquitlam

Coquitlam

Projected Demand


1991 1996 2001 2006 2011 2016 2021 2026 2031 2036 2041 Year

Exhibit 8-11. GVRO Water Supply Alternatives

B-24

" ,

Project costs were developed for the specifzc elements of each option.

Costs and revenue were scheduled for each option.

Net present value was determined for each option.


been considered because their size and cost are unlikely to be affected by choice of the supply source. Required improvements were phased in over a 40-year period.

Project costs used in the analysis of the six supply options involved capital, O&M, and purchased water costs. Unit and lump sum costs, as appropriate, were developed based upon past GVRD construction projects and recent studies conducted by GVRD consultants. For those options involving full use of Coquitlam, revenue from hydropower generation was included in the analysis. These costs, in 1993 dollars, are summarized in Exhibit B-12.

Implementation schedules were developed for each option. For those options involving the construction of a new Seymour Falls Dam, the new dam and associated water filtration plant were scheduled to be on line in the year 2005 (Options 1, 3, and 5). For options requiring water filtration plants at all three sources (Options 3 and 4), the treatment plants were also assumed to be on line and in use by the year 2005. For Coquitlam options (Options 2, 4, and 6), the existing Seymour Falls Dam would be repaired by 1997 and a new agreement with B.C. Hydro would be reached by 2005.

Based on the implementation schedule for each option, capital expenditures, operation and maintenance costs, purchased water costs, and revenue from hydropower generation were allocated over the analysis period. A net present value determination was then made of each option for purposes of economic comparison. The economic criteria used for the analysis are:

o Inflation Rate = 3.5 percent o Real Discount Rate = 4.8 percent o Nominal Bond Rate = 8.5 percent o Bond Term = both 10 and 20-year terms were analyzed

The net present value of the options for the period 1994 through 2041 is presented in Exhibit B-13 on page B-28.

B-25


Exhibit 8-12 Project Costs for Supply Options

Capital

Project Element Cost (1993$)

Repair Existing Seymour Falls Dam $15 million

New Seymour Falls Dam $90 million

Transmission Pipeline Unit cost ranging from $828/ft for 150-inch diametre pipe to $228/ft for 24-inch diametre pipe

Pumping Station Unit cost based on dollarslHP = 1,763.71 - O.oI8 HP

Filtration Plant Based upon consultant studies with variable costs in $1,000 as shown below.

Filtration Process Costs

Peak Hydraulic Capacity Unit Capital Costs (1,000 $IMLlday)

Conventional Conventional ML/day Direct Conventional with Ozone Ozone and GAC

455 948.0 1,117.1 1,206.9 1,759.5

910 890.6 1,042.9 1,129.3 1,681.9

1,365 833.2 968.7 1,051.6 1,604.2

1,820 775.8 894.5 974.0 1,526.6

2,275 718.4 820.2 896.3 1,488.9

2,730 660.9 746.0 818.7 1,371.3

Operation and Maintenance

Project Element Unit Costs (1993$)

Pumping Power Five centslkilowatt-hour

Filtration Plant Direct = $7,700/peak MLlday

Conventional with ozone = $9,240/peak MLlday

Conventional" with ozone/GAC = $11,11 O/peak MLiday

Payment to B.C. Hydro Long-term loss of energy at the long-run marginal cost as per the Agreement. At the 1991 rate of $13 per megalitre/day, this payment is $5.82 million per year.

Loss of generating capacity at the long-run marginal cost. The cost is estimated as $40,000 per megawatt capacity per year. For a 73 megawatt plant, the annual cost is $2.92 million.

Revenue

Hydropower generation declining Under Options 1,3, and 5, which assume Coquitlam ownership in the over time. year 2031, the annual revenue declines from $6.9 million in 2031 to

$6.6 million in 2041, due to increasing use of power to meet GVRD's own needs.

Under Options 2, 4, and 6, which assume Coquitlam ownership in the year 2005, the annual revenue declines from $6.9 million in 2005 to $2.3 million in 2041. All revenue is calculated in 1993 dollars.

B-26

-

Net present value provides a valid com-parison of option costs.


7.6 Economic Comparison of Options

The net present value (NPV) analysis was made for both a 20 and 50 year period to allow for a relatively short and long term comparison. It should be noted, that because of the method of repayment of the bonds, the NPV does not contain all of the funds which must be repaid. There are still unpaid balances on bonds remaining at the end of the 20 and 50 year intervals which do not appear in the NPV. However, where the largest capital expenditures (filtration plant and dam construction) entered the financial stream in the same year for each option, as applicable, the analysis provides a valid comparison of option costs. Also, the financing term or evaluation period does not change the relative economic ranking of the options.

To better summarize and display this comparison, the NPV for 20 year bond term financing over a 50 year period is shown in Exhibit B-14 together with the primary elements of each option. The dominance of the filtration plant costs is apparent (Phases II and ill, plus Coquitlam filtration under water treatment).

From an economic standpoint without consideration of other criteria, this analysis has shown that:

DUsing Coqllitlam as the first selection of new source is favoured over Seymour for Options 1 and 2 (cWorarnination) and Options 5 and 6 (chlorination) without concerns for disinfectant by-products. In both comparisons, the NPV of the Coquitlam option is about 60 percent of the NPV for the Seymour Option.

o For the alternatives where disinfectant by-products are a concern (Options 3 and 4), the NPV for the Seymour option is about 95 percent of the NPV for the Coquitlam option even though a new dam is built. This difference is basically due to the higher cost of the Coquitlam filtration plant compared to the Seymour plant.

o Full use of Coquitlam as the next source (Option 2) is the most cost effective supply plan, without regard for water quality issues and other important criteria.

B-27


Exhibit 8-13 Net Present Value of Options

With lO-year Financing With 20-year Financing

Net Present Net Present Net Present Net Present Value 1994-2013 Value 1994-2041 Value 1994-2013 Value 1994-2041 (1993 $Million) (1993 $Million) (1993 $Million) (1993 $Million)

Option 1: Seymour $706 $995 $644 $1,054 Chloramination

Option 2: Coquitlam $471 $594 $465 $619 Chloramination

Option 3: Seymour Chlo- $1,107 $1,545 $991 $1,642 rinationlDBPs*

Option 4: Coquitlam Chlo- $1,296 $1,620 $1,179 $1,729 rinationlDBPs*

OptionS: Seymour $743 $1,051 $676 $1,114 Chlorination +

Option 6: Coquitlam $526 $674 $514 $703 Chlorination +

* Disinfection by-products are a concern. + Assumes disinfection by-products are not a concern.

Exhibit 8-14 Summary Comparison of Options

Cost (1993$ Elements of Options Million)

Options and Upgrade or Secondary Next Source Water Quality Build New Net Present

Disinfectant (year) and Treatment Seymour Falls Dam Value

Option 1 Seymour (2005) Phase I plus filter Build new, higher $1,054 Chloramination Coquitlam (2031) Seymour (Phase II) dam

Option 2 Coquitlam (2005) Phase I Upgrade existing dam $619 Chloramination

Option 3 Seymour (2005) Phase I, II, III, plus Build new, higher Rechlorination filter Coquitlam dam

Coquitlam (2031) 20 - 30 rechlorina- $1,642

tion stations

Option 4 Coquitlam (2005) Phase I, II, III plus Upgrade existing dam Rechlorination filter Coquitlam $1,729


Option 5 Seymour (2005) Phase I plus filter Build new, higher Rechlorination Coquitlam (2031) Seymour (Phase II) dam $1,114


Option 6 Coquitlam (2005) Phase I Upgrade existing dam Rechlorination 45 - 60 rechlorina- $703

tion stations

B-28

A new agree-ment is needed with B.C. Hydro to expand use of Coquitlam Lake.

In predicting future demand, it is assumed that a regional water conserva-tion program will be imple-mented.


Section 8.0 Conclusions

Studies conducted by the GVRD over the past several years have evaluated the status of the existing regional water supply system and addressed issues of future growth and supply. The primary conclusions to date of this Comprehensive Regional Water Supply Study are summarized as follows:

o

o

Storage, diversion, and use of water from the eXIstmg supply sources are fully authorized by Provincial water licenses. In addition, conditional licenses are held by the GVWD in sufficient quantity to allow for construction of a new Seymour Falls Dam to an elevation which optimizes the watershed supply potential.

Although current GVWD use of Coquitlam Lake is authorized by Provincial license and agreement with B.C. Hydro, a large portion of the watershed yield is licensed to B.C. Hydro for power generation. Further agreement with B.C. Hydro, possibly involving complete buy-out of hydropower rights and interests, is required to fully utilize Coquitlam Lake for water supply purposes.

o The population served by the GVWD regional system is forecast to grow from about 1.6 million people in 1991 to 2.8 million in the year 2041.

o

o

Currently developed supply from the Capilano, Seymour and Coquitlam watersheds is adequate to meet present regional needs in most water supply years. During periods of drought, as experienced in 1992 and 1993, summer curtailment of water use is required.

Predictions of future regional water supply needs were made separately under these three assumptions (1) past trends in growth of per capita water consumption will continue, (2) implementation of a water conservation program will reduce the rate of per capita water consumption growth, resulting in a 20 percent reduction below the first (trend) prediction by the year 2041, and (3) implementation of a more aggressive water conservation program, including metering of all residential customers, will result in a further reduction of at least 10 percent by the year 2041. The assumptions under prediction (2) were adopted for purposes of this study.

B-29

A new source of supply is required by the year 2005.

After evaluation of29 alterna-tives for new source develop-ment, expansion of Seymour and Coquitlam were determined most viable.

Repair of exist-ingSeymour Falls Dam must be addressed.

Net present value of options range from $619 million to $1.7 billion.

Filtration is dependent upon selection of secondary disinfectant.

o

o

o

o

o

o


The demand forecast was compared to the supply available from full utilization of the three existing sources as currently developed, with some improvements provided to remove impediments to flow in the transmission facilities (removal of hydraulic constraints). Based on this comparison, a new source of supply is required by the year 2005 to meet predicted regional annual average daily demands.

Alternative future supply sources local to the GVRD regional area were identified, evaluated and compared as to supply potential and project cost. Sources considered were (I) further development of the three existing watersheds, (2) new development of the Fraser River, Pitt River, or Pitt Lake, and (3) groundwater development. In all, 29 variations for use of these sources were considered. It was determined that expanded use of the Seymour watershed and/or Coquitlam watershed were the most viable sources for meeting the regional quality and supply needs through the year 2041.

In considering options for expanded use of the Seymour watershed, it was recognized that the existing Seymour Falls Dam must be modified at an early date to meet current standards for safety under earthquake conditions. Remedial cost is estimated to be $15 million.

Upon merging the results of the supply study with the Drinking Water Quality Improvement Plan (DWQIP) and dam safety investigations, six options involving Seymour and Coquitlam were identified. These options cover the full range of water treatment from no filtration of any source to full filtration of all sources. All six options will provide ample supply to meet regional needs through the year 2041.

A NPV analysis was conducted of each option over the 50 year planning period. The analysis included capital costs, operation and maintenance costs, and power revenues associated with Coquitlam Lake options. A range of costs was determined from a low of $619 million for Option 2 to a high of $1.7 billion for Option 4 (all in 1993$). This range of costs is driven primarily by the number of water filtration plants required in an option.

It was determined that the extent of filtration required is directly tied to selection of the secondary disinfectant to be used by the GVRD. Based upon the water quality studies described in Appendix A, chloramine and chlorine are both under consideration.

B-30

.. jill


Generally, more extensive filtration and higher costs are associated with the options using chlorine as the secondary disinfectant.

o Four options involving rechlorination have been evaluated. Of these, two options (Options 5 and 6) assume that disinfectant byproducts associated with the use of chlorine will not exceed current or future water quality guidelines and water filtration will not be necessary. The other two options (Options 3 and 4) assume that disinfectant by-products will be a future concern and that filtration of all sources will be required. Based upon current trends in government guidelines and regulations, there is the likelihood that lowering of water quality standards for allowable concentrations of disinfectant by-products will take place in the foreseeable future. For this reason, Options 5 and 6 are not considered viable for long range planning.

Exhibit 8-15 Water Treatment Options

With Chloramine as Secondary Disinfectant

Option 1

Moderate CostlHigh Water Quality

D Seymour is next new source of supply,

D A new and higher Seymour Falls Dam is constructed consistent with earthquake standards,

D Filtration of Seymour is immediate, and

D Flexibility is retained for future improvements.

Option 2

Lowest CostIModerate Water Quality

D Coquitlam is next new source of supply,

D Seymour Falls Dam is upgraded,

D Filtration can be deferred, if desired, and

D Flexibility is retained for future improvements.

With Rechlorination as Secondary Disinfectant

Option 3

High Cost/High Water Quality

D Seymour is primary new source,

D A new and higher Seymour Falls Dam is constructed, and

D Filtration of all sources immediately.

Option 4

Highest CostlHigh Water Quality

D Coquitlam is next new source,

D Seymour Falls Dam is upgraded, and

D Filtration of all sources immediately.

B-31

To screen the remaining four options to a lesser number requires a basic decision. That decision is whether chlorine or chloramine is selected as the secondary disinfectant. Once that decision is made, the choice of options between Seymour and Coquitlam is as shown in Exhibit B-15. At this point, it is expected the selection will be based on many factors, including economic efficiency.

Appendix C - Seymour Falls Dam Safety

Appendix C Seymour Falls Dam Safety Table of Contents

Introduction ................................................................................. C-1

Concrete Dam ............................................................................. C-2

Flood Conditions ......................................................................... C-6

Bedrock Foundation .................................................................... C-7

Stability of Concrete Dam Elements ............................................ C-7

Buttresses - Lateral Stability ........................................................ C-8

Buttresses - Upstream/Downstream Stability .............................. C-8

Intake .......................................................................................... C-8

Geological Setting ..................................................................... C-1 0

Description of the Earthfill Dam ................................................. C-11

Stability of the Earthfill Dam ...................................................... C-13

Conclusions and Summary ....................................................... C-14

Glossary .................................................................................... C-16


Appendix C Seymour Falls Dam Safety List of Exhibits

Exhibit C-1 Seymour Falls Dam Site Plan ................................ C-3

Exhibit C-2 Seymour Falls Dam Buttress Dam ......................... C-4

Exhibit C-3 Seymour Falls Dam Buttress Dam Non-Overflow Buttress ........................................... C-5

Exhibit C-4 Stability Assessment-Phase II Seymour Falls Dam - Section A .......................................... C-12

I _

Due to possible earthquake accelerations ex-ceeding original design, an eval-uation of the seismic stability of Seymour Falls Dam was completed.

Two earthquake conditions were considered for evaluation.


Appe~dix C Seymour Falls Dam Safety

Introduction

Seymour Falls Dam is located on the Seymour River, approximately 18 km north of Burrard Inlet, at about El. 215. The facility is owned, maintained and operated by the Greater: Vancouver Water District (GVWD) and is used for potable water supply.

Seymour Falls Dam is a 450 m long composite structure, the eastern half of which consists of a slab and buttress concrete section. The western half is an earthfill embankment and is founded on alluvial sediments which vary in thickness from zero at the concrete/earthfill transition to more than 120 m at the western abutment. The embankment is protected by an extensive upstream impervious earthfill blanket. The dam was constructed to a height of 33 m with provision for future raising of a further 17 m. The 30 year old structure is in excellent condition, evidence of a high standard of construction. It was designed in 1958 and construction was completed in 1961.

In the past 33 years since the dam was built, there has been a growing awareness of the tectonic activity in the Pacific Rim, and it is now believed that significantly higher earthquake accelerations could be experienced at the site than were assumed in the original design. Therefore, an evaluation of seismic stability of the dam has been carried out using current seismic design methods.

In accordance with the classification system recommended by the International Commission on Large Dams (ICOLD), Seymour Falls Dam is rated as a large dam. Consequently, two earthquake conditions have to be considered in the dam stability evaluation, namely the Design Basis Earthquake (DBE) and the Maximum Design Earthquake (MDE).

According to ICOLD criteria (ICOLD, 1983) the structures are required to withstand the DBE without damage. Damage during the MDE, however, is acceptable provided it does not cause failure resulting in uncontrolled release of reservoir water. Because the dam is classified as a high hazard structure with potential for major damage and loss of life if it fails, the MDE is taken as the Maximum Credible Earthquake (MCE).

The DBEIMCE requirements are used by most large agencies in North America and world wide. The requirements are consistent with B.C.

C-l

Seymour Falls Dam is classified as a high hazard dam.

The dam must also pass the Probable Maxi-mum Flood.


Hydro seismic guidelines, according to which Seymour Falls Dam is classified as a high incremental hazard structure due to downstream damage potential.

The existing dam was designed for earthquake accelerations of 0.1 g in the horizontal direction and 0.05 g in the vertical direction. The horizontal earthquake forces were taken to act parallel to the axis of the dam for the design of the buttresses, portal frames and struts between the buttresses.

Ground motions associated with current perceptions of earthquake risk are substantially larger than those used in the original design. The MCE horizontal ground acceleration is 0.5 g, a five-fold increase compared to the original design. In addition, the last twenty-five years has produced an increasing awareness and knowledge of the danger presented by loose granular soils in earthquake loading. (The earthfill portion of the dam is extensively underlain by loose granular soil.)

In addition to satisfying current earthquake safety criteria, the dam also must pass the Probable Maximum Flood (PMF) without failure and sudden, uncontrolled, release of reservoir water.

The spillway was designed using the standard of practice of the late 1950s which allowed for the l000-year return period. Current practice requires that release facilities be able to safely pass the PMF, the return period for which is watershed dependent and is usually far less than once in a thousand years.

Concrete Dam

The concrete structure is a typical Ambursen or slab and buttress type dam, similar to others which were constructed in the period between 1910 and 1940. The general arrangement ofthe dam is shown on Exhibit C-l, a site plan.

The structure consists of 27 buttresses at 6.7 m centres supporting 28 face slab spans. From west to east, the spans comprise five bays of nonoverflow section of varying height, three bays of spillway, one bay of intake structure, nine bays of spillway, three monolithic bays through which the axis of the dam rotates 30° in an upstream direction, then seven bays of non-overflow section of varying height. A downstream elevation is shown in Exhibit C-2, and a typical non-overflow section is shown in Exhibit C-3. A storage room and small hydro powerplant occupy the bays adjacent to the intake.

C-2

i-i


1----, I . ,~

:----'----',,---:----"-0;:----- -- ----------. - t---,--------. I

I LaKe b/onkef

I

;'

Note: All contour elevations are infeet (GVWD Datum).

Exhibit C-1. Seymour Falls Dam Site Plan

C-3

~

DOWNSTREAM ELEVATION

Exhibit C-2. Seymour Falls Dam Buttress Dam

-6" '" <I>

[ ~.

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f l:: ... ~ ~

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-


Ci~~·J);o"IP~~ ·/bm1Pcfholes Ibr honcfroJ/ PO:>""

.. -1ff----tI----..,.---'-~.b .. l.:...:;.._:,..:_"=""~ .-£:.1765.50

cho.~lyp

TYPICAL NON- OVER FLOW BUTTRESS

Note: All elevations are infeet (GVWD Datum).

Exhibit C-3. Seymour Falls Dam Buttress Dam Non-Overflow Buttress

C-5

bridge

The dam was designed to accommodate being raised.

Probable Maxi-mum Flood outflow estimate is 1143 ems.


The upstream face slab and the buttresses were designed for the raised height of the structure and the vertical downstream edges of the buttresses are provided with shear keys to facilitate their enlargement to the final size when the dam is raised.

Intake channels are formed between two adjacent buttress walls that extend upstream beyond the face slab. The inlets to the two water supply pipes are located at the bottom of each channel. Water passes through trash racks, hydraulic control gates, and traveling water screens before entering the two, 2 m diameter water supply pipes.

The overflow spillway occupies 12 bays and is 76 m in length. The ogee crest is at El. 213 and the apron lip is at El. 207.5, about 21 m above the bedrock river bed. Two low level outlets fitted with 1.5 m diameter Howell-Bunger valves are provided near the east end of the spillway at El. 190.

At the west end of the concrete structure a mass concrete gravity transition structure carries earth embankment loads to the foundation to prevent these forces from acting on the buttresses.

Flood Conditions

The Seymour reservoir is about 6.5 km long with a surface area of 2.6 km2• The total storage capacity is 25 million cubic metres with the reservoir level at the crest of the spillway at El. 213. The catchment area is 126km2•

The original design flood for the spillway was 990 cubic metres per second (cms), which was estimated as the flood with a WOO-year return period. The corresponding reservoir level required to pass the WOO-year design flood was El. 216.3. At this reservoir level, there would be 2.1 m of freeboard. (The WOO-year flood is now estimated to have a peak discharge of 776 cms.)

The design peak PMF outflow is estimated to be 1143 cms and would result in a maximum reservoir level of El. 216.8 which is 1.7 m below the dam crest and 0.8 m above the top of the existing impervious core. This PMF would occur during winter. The tail water level at PMF is estimated to be at El. 191 m.

The GVWD installs stoplogs on the spillway, usually between June 1 to late August, to increase reservoir capacity during summer months. This increases the spillway crest level by 1.8 m, from El. 213 to El. 214.8. The maximum summer PMF outflow is estimated to be 671 cms, and with the

C-6

Seymour Falls Dam cannot provide flood control.

Generally, the bedrock is complete.

Strengthening and upgrading of elements of Seymour Falls Dam would be required.


stoplogs in place, would result in a maximum reservoir level of El. 217.4. This is 0.6 m higher than the level resulting from the maximum (winter) PMF without stoplogs, and is 1 m below the dam crest.

The Seymour reservoir is drawn down in the summer months and controlled refilling takes place though the fall and winter.

There is little opportunity to regulate flood outflows from Seymour Falls Dam. Floods are discharged without regulation once reservoir levels are higher than the spillway crest. Operations of low-level outlets during an extreme flood event would cause a slight reduction in flow rate over the spillway but would not affect the total discharge released downstream. Analysis of floods in 1981 and 1983 and simulation of the PMF routing demonstrate that Seymour reservoir has little routing effect on reducing flood peaks. For the Seymour reservoir, the peak flood outflow (winter PMF) is estimated to be 1,140 cubic metres per second with the maximum reservoir level at El. 216.8 or 1.7 m below dam crest, assuming El. 212 as initial reservoir level. The existing dam can handle the winter and summer PMF without modifications.

Bedrock Foundation

The bedrock foundation of Seymour Falls Dam consists of highly competent, strong and non-compressible quartz diorite. Seepage through the foundation is well controlled by the tightly closed joints, although seepage pressures may be high locally.

Dam stability may be affected only by one discontinuity set on the east abutment .which dips 12-22° in a downstream direction. This joint set is moderately continuous and presents possible sliding surfaces beneath the east abutment buttresses and within the foundation.

Due to the high strength of the intact rock and the tightly interlocked blocks by minor weathered discontinuity surfaces, the shear strength of the rock mass is very high.

Stability of Concrete Dam Elements

During the studies, it was determined that certain elements of the Seymour Falls concrete dam would require strengthening and possibly upgrading. Investigations were undertaken and designs for the remedial works were prepared. This section describes the investigations and design work carried out for those concrete dam elements which required strengthening and/or upgrading.

C-7

The cross-valley vulnerability of the buttresses can be addressed with shear walls.

Post-tensioned anchors will prevent sliding of buttresses.

Damage to the in-take would pro-bably occur under both evaluation earthquakes.


Buttresses - Lateral Stability

It was found that the concrete dam would not be able to withstand either the MCE or the DBE loading in a cross-valley direction. The fundamental problem is that the individual buttresses do not have sufficient lateral strength to support the inertia loads generated during a cross-valley earthquake. Failure of a single buttress would lead to a catastrophic failure of the entire concrete dam due to the limited redundancy in the structure. Alternative methods for stabilizing the buttresses for crossvalley earthquakes were reviewed and the resulting recommendation was to install two rows of 50 cm thick concrete shear walls, parallel to the axis of the dam.

The shear wall concept provides lateral support for every buttress in the direction of the cross-valley earthquake. This allows the inertia loads to be carried by in-plane resistance of the shear walls, which is a more effective load path than through the lateral load carrying mechanism of the buttresses by themselves. The addition of the shear walls will reduce the stresses in the buttresses so that catastrophic failure will not occur.

Buttresses - Upstream/Downstream Stability

The assessments indicate that the buttress dam does not meet the required safety criteria in the upstream/downstream direction under DBE and MCE loading, and that post tensioned anchors are needed in the buttresses to improve the sliding stability to the required level of safety. The buttress dam is essentially a series of upstream face slabs simply supported by the sloping face of vertical buttress walls which have limited strength to resist cross-valley rotation about their base. The whole system achieves lateral stability by being wedged in position between the east rock abutment and the concrete gravity transition block. Sufficient movement of any of the buttresses in the downstream direction would cause adjacent upstream face slab panels to fallout between the buttresses, resulting in collapse of at least several bays of the buttress dam.

The engineering work analyzed each individual buttress and determined the number of anchors that are required to be installed.

Intake

A check was made of the stresses in the intake structure and significant overstress was found to occur in a number of locations. It became evident that damage probably would occur to the upper part of the intake structure under the MCE and the DBE loadings. In fact, it became the aspect which

C-8

-

Three alternative remedial works schemes were developed.

Alternative 1 is costly and does not eliminate the risk.

Alternative 2 requires lengthy cessation of intake operation.


now has a significant influence on the viability of raising the dam in the future.

A total of six different finite element analyses were performed on the Intake Substructure. Each analysis attempted to find a remedial works solution by modifying the structure, either by strengthening various portions of the structure or by removing portions.

The intake was analyzed under MCE loading in the cross-valley direction. As the seismic loading is applied parallel to the upstream face slabs, no hydrodynamic loads were applied to this face slab. However, the vertical intake walls protrude upstream from the inclined upstream face slab and will be subject to hydrodynamic loading.

Three alternatives for the remedial works to the intake were considered and evaluated. These are:

o Alternative 1: Modify the intake to comply with the requirements as analyzed by the finite element model and accept some damage under MCE loading;

o Alternative 2: Modify the intake substantially to ensure that is complies fully with all requirements;

o Alternative 3: Not modify it at all except for the construction of the shear walls and accept the risk of some damage occurring under DBE and MCE loading.

The evaluation of the three alternatives is as follows:

Alternative 1

This alternative, to partially demolish the intake and to install anchors, lowers the risk of the intake becoming inoperable after a DBE event, but does not eliminate it. It also limits damage after a MCE, but does not eliminate it. The cost of implementing these modifications is considerable and will possibly require the operation of the reservoir to cease for a short period of time during construction.

Alternative 2

This alternative, complete demolition of the protruding intake walls and reconstruction, will theoretically result in little damage to the structure after a MCE and will enable the reservoir to be fully operable after a DBE. The cost of executing these modifications would be substantial and would

C-9

Alternative 3 has some risks, but uncontrolled releases would not occur.

Alternative 3 is recommended in conjunction with emergency plan-ning.


result in the cessation of reservoir operations for a substantial period of time.

Alternative 3

This alternative, doing nothing to the intake walls and constructing the shear walls only, would result in the risk that the operation of the reservoir may be stopped for a short period of time after DBE. The length of this stoppage would depend upon the emergency planning done beforehand to get the reservoir back into operation, but could be reduced to a few hours if proper planning is carried out. Damage to the intake in terms of cracking of the concrete walls and damage to the screens, gates and trash racks is expected to be considerable after a MCE. Leakage would also occur through the bulkhead wall, but would not be significant in terms of water release, and could be readily repaired. Collapse of the intake structure is not considered likely, and damage to the portion of the dam that provides the main structural strength to support the reservoir loading would be minor. Uncontrolled release of the impounded water would not occur.

In view of the possibility that this dam could be raised in the near or intermediate future, the cost of implementing the partial demolition option is not justified as this alternative is considered to be unsuitable for the dam in its raised configuration. The intake, as originally conceived, in the raised configuration, is also unsuitable.

It is therefore recommended that the alternative of doing no remedial works to the intake except for the construction of the shear walls be implemented.. This is considered to be the most appropriate alternative to minimize the costs of the remedial works and accepting a small risk of a DBE causing a short stoppage of operation of the reservoir. In the long term, if the dam is to be raised, a completely new intake should be considered as part of the raising of the dam. With careful planning, the construction and commissioning of this intake would not affect the operation of the reservoir.

Geological Setting

The Seymour Falls dam site is located at a major constriction in the Seymour River Valley. The constriction is formed by a large alluvial fan cone projecting outward from the west rock Wall, and by a bedrock spur projecting outward from the east rock wall at right angles to the valley axis. The fan cone is the deposit of a tributary stream, Cougar Creek and is known as the Cougar Creek Fan.

C-IO

Cougar Creek Fan is a loose, deep deposit.

The earth fill dam is built on top of Cougar Creek Fan and is protected by an upstream "blanket. "


Drilling on the lower slopes of Cougar Creek Fan confirmed the overall make up of the deposit. The fan material varies from boulders over 3.7 m in diametre to fine sand. Cougar Creek Fan deposits are relatively loose and extend from ground surface to about El. 130. Ground surface is about El. 200 at the dam and rises to about El. 255 at the west valley wall. Below El. 130, dense pre-glacial deposits are thought to exist (Campbell, 1960).

The density of the Cougar Creek Fan deposit, as revealed by the Becker drilling technique is summarized as follows:

o Below the original ground level down to about El. 192, the Fan is dense. This elevation range is the known subaerial part of the deposit;

o From El. 192 to about El. 173, the Fan is loose; and

o Below El. 173, the Fan is dense.

Description of the Earthfill Dam

The existing earthfill dam extends across the valley from the rock ridge to tie into the Cougar Creek Fan at El. 218.5. The east abutment of the existing earthfill dam is founded on rock.

The embankment cross section consists of six major zones, as shown on Exhibit C-4. The impervious section of the embankment is an inclined central core composed of clayey silt. Upstream of the core, a transition section of sand and gravel was constructed between the core and the granular shell. The upstream granular shell is a well graded mixture of sand, gravel, cobbles and boulders. The outer 6 m of the upstream shell consists of boulders greater than 0.6 m in diametre. The core extends below the upstream shell and is connected to an impervious blanket of clayey silt at the toe of the dam. The impervious blanket extends about 200 m into the reservoir to tie into a natural lacustrine silt and clay layer. The impervious blanket is 1.5 m thick and was constructed in two phases consisting of a "lake blanket" in the pre-existing reservoir and a "land blanket" over the Cougar Creek Fan sediments. The land portion of the upstream blanket is covered with a protective layer of well graded sand, gravel, cobbles and boulders. The lateral extent of the upstream blanket is shown on Exhibit C-1.

The dam core extends to El. 216 and the crest is overlain by a filter sand 0.6 m thick, then sand and gravel. The crest of the dam is paved with asphalt with a finished grade at about El. 219. Downstream of the core are fine and coarse filter zones of clean, well graded sand, and clean gravel,

C-ll

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Significant de-formations could occur under the DBE, while the MeE would likely lead to uncontrol-led release of water due to ex-tensive liquefac-tion of the dam's foundation.

The earthfill dam and its founda-tion can be up-graded through a four-step program.


respectively. The coarse filter also extends horizontally along the stripped ground surface to the downstream toe of the embankment. The downstream shell is a random fill zone constructed of pit run gravel and sand with some cobbles.

Stability of the Earthfill Dam

Using data obtained from an extensive program of exploratory drilling and geophysical surveys of both the dam and its foundation, the liquefaction potential beneath the dam was analyzed. The results of the analyses indicated that certain soil units in the earth dam's foundation will experience large pore pressure rise and could potentially liquefy under DBE loading and cause significant deformations to the existing dam. As a result of these deformations, failure of the existing dam and release of the reservoir could occur.

Under the MCE almost complete liquefaction of the existing foundation is anticipated. This would probably lead to a catastrophic release of the reservOIr.

The Cougar Creek Fan which forms the west abutment of the earth dam, was also assessed for its resistance to earthquake loading. Generally, the results of this assessment are that it is considered to be stable under the DBE and the MCE although some localized deformations may occur upstream of the dam.

The recommended remedial works to address deficiencies related to the earth dam are designed to meet the criteria and are consistent with current practice. The steps to be undertaken in the remedial work program are as follows:

o

o

o

Partially excavate the existing dam downstream of the core.

Densify the foundation to El. 176 or to rock by a combination of blasting and dynamic compaction.

Reconstruct the dam on the densified foundation. The new dam centreline is to be displaced a maximum of about 43 m downstream, but ties into the existing dam at the west abutment and at the concrete transition block.

o The dam cross section is to include a thick drain and thick filters downstream of the core to allow for some cracking of the dam, differential movement between the earthfill dam and the concrete dam, and total failure of the upstream impervious blanket.

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Five sets of remedial works are required for the dam supply to safely withstand seismic loading.


o As a result of differential movement between the earthfill dam, and/or total failure of the blanket, damage may occur to the earthfill dam during an MCE or DBE. This would be addressed by an emergency action plan which would be prepared to respond to any damage. This action plan may include lowering the reservoir water elevation to reduce leakage and reduce the potential for long term soil piping failure, if required.

Conclusions and Summary

The engineering studies recommend extensive remedial work to both the concrete and earthfill dams to satisfy the safety criteria under DBE and MCE loading.

The remedial works recommended are compatible with the possibility of future raising of the earthfill dam.

No remedial works are required for the revised PMF loading nor to allow passage of the PMF over the dam.

The remedial works required for seismic loading are:

o Construction of transverse walls between the buttresses, denoted as shear walls, to improve stability of the buttress dam in the crossvalley direction. The walls are placed along two alignments, one along the axis of the dam or as close to the axis as practicable, and the other upstream of the axis of the dam. They are called the Downstream and Upstream shear walls respectively.

o Installation of post-tensioned anchors in the buttresses and transition block to improve stability in the upstream/downstream direction.

o Modifications to isolate the spillway bridge using laminated rubber and steel bearing pads to reduce transfer of the cross-valley seismic loads from the bridge into the spillway buttresses.

o Drilling of additional drainage holes on the east abutment to revitalize the drainage system and to improve stability of the rock abutment.

o Reconstruction of the earthfill dam immediately downstream of its present position. This would entail four stages of construction:

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• Installation of a cofferdam on the existing upstream berm to maintain the reservoir.

• Excavation of the central and downstream portions of the earthfill dam.

• Dynamic compaction and foundation blasting to consolidate the foundation materials to the required density.

• Reconstruction of the earthfill dam downstream of the original alignment on compacted ground.

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Glossary

alluvial soils

anchors

buttress

coffer dam

diorite

discontinuity set

finite element method

gravity transition block

hydrodynamic

intertia

joints or joint set

key

lacustrine soils

liquefaction


Transported by running water.

A piece of equipment which transfers load from the structure to the foundation.

A concrete pier at right angles to the slab, built to resist water pressure and transfer load into foundation.

A temporary dam, usually used to give access to an area which is ordinarily submerged.

A granite-like, granular rock.

See joints/joint set below.

A method of structural analysis to handle two and three dimensional structures such as plates, shells and solids.

A structural block which is prevented from overturning by its weight alone.

Relating to the flow or movement of water over weirs, through openings, pipes and channels, and against structures.

Resistance of a structural element to bending or to rotation.

A discontinuity in rock, where it breaks easily.

Mechanical bond or that type of it achieved by an irregular or serrated surface in a construction joint.

Deposited in quiet lakes.

A saturated soil that is loose is liable to liquefaction when it is shocked by earth tremors. The soil becomes temporarily quick and a flow slide may develop.

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mass concrete

ogee crest

piping

pore pressure

portal frame

post-tensioned

shear

shear strength

shear wall

slab

spillway

stoplogs

stress

subaerial

tectonic

trash racks


Concrete without reinforcement.

Spillway which is S-shaped in profile.

Subsurface soil erosion by the movement through a dam or cofferdam of a stream of water and soil.

The pressure of water in a saturated soil.

A frame consisting of two uprights rigidly connected at the top by a third member.

A method of prestressing concrete in which cables are pulled and locked in place after being pulled to designed loads.

The load acting across a beam or structural element near its support.

The stress at which a material fails in shear.

A interconnected reinforced-concrete wall running the full height of the buttress to stiffen them against the earthquake loading.

A comparatively thin part of reinforced-concrete between buttresses.

An overflow channel, particularly one over a dam.

Removable individual concrete boards stacked across the crest of a spillway which provide a means of raising the reservoir level when the spillway is not needed for releasing floods.

The force on a member divided by the area which carries the force.

Formed on the surface of the land.

Relating to deformation of the earth's crust or to structural changes caused thereby.

Parallel bars or a screen across the entrance to a raw water intake to catch floating debris.

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Responses to Commonly Asked Questions

Responses to Commonly Asked Questions and Public Concerns

Is the water safe to drink?

Yes. The water is currently safe to drink as determined by testing on a daily basis by the GVRD laboratory. However, the regular testing has also shown that the region's drinking water does not consistently meet drinking water quality standards and so the potential exists for the water to become unsafe if drinking water improvements are not carried out.

Which municipalities have unacceptable bacteria levels in their drinking water?

Unacceptable bacteria levels (non-disease causing indicators of poor water quality) occur to varying degrees in all municipalities and no municipality has maintained continuous compliance with the new B.c. Safe Drinking Water Regulation in recent years.

Why is a secondary disinfectant required?

A chlorine or chloramine disinfectant residual is required to control bacteria levels and restrict the growth of disease causing bacteria should they accidentally enter the water distribution system.

Why not use home filtration or bottled water instead of treating the water?

Relying on bottled water or home filtration for the entire community is much more costly than regional water treatment and not as reliable. Bottled water is not acceptable to the Medical Health Officers because it will not provide the protection required to meet public health objectives of providing affordable, clean, safe water to all consumers in the GVRD service area.

Would improved maintenance of pipes by cleaning (pigging) the water pipes reduce bacteria levels so that chloramine or chlorine are not required?

No. Flushing and pigging of water mains were identified in the Drinking Water Quality Improvement Plan (DWQIP) as good water system

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maintenance practices. They are required as part of the solution to the bacteria problem, but will not replace the need to maintain a disinfectant residual (adequate chlorine or chloramine level) throughout the system.

Can ozone be used as a secondary disinfectant instead of chlorine or chloramine?

No. Ozone can be used as a primary disinfectant, but not as a secondary disinfectant. Testing by GVRD's consultants indicated that ozone can be added as a primary disinfectant to filtration plants once they are installed for the GVRD, but chlorine or chloramine must still be added to protect the water entering the municipal water systems as is commonly practiced where ozone water treatment is used throughout North America and Europe.

Can hydrogen peroxide be used instead of chlorine or chloramine?

No. Expert consultants have advised us that hydrogen peroxide is not used by any cities as a secondary disinfectant. It is being tested in the USA with ozone to form "peroxone," a primary disinfectant for special water treatment problems. Hydrogen peroxide is a good oxidant, but a poor disinfectant.

Would filtering the water eliminate the use of chlorine?

No. Filtration would not eliminate the use of chlorine, but filtration would reduce somewhat the amount of chlorine or chloramine required in the distribution system. However, an adequate amount of chlorine or chloramine residual would still be required throughout the distribution system to keep the presence of bacteria at acceptable levels and to meet drinking water standards.

Are there any other organisms besides Giardia that the GVRD is concerned with?

Yes. A microorganism called Cryptosporidium is also a concern. It is a protozoan that has been identified as the cause of a ·large waterborne disease outbreak in Milwaukee, Wisconsin. Cryptosporidum is smaller in size than Giardia and is very resistant to disinfection with chlorine. Removal or inactivation of Cryptosporidium requires much higher disinfectant residuals and optimized filtration treatment. Studies are being

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conducted throughout North America on other treatment technologies for the removal of Cryptosporidium including ozone. Preliminary results indicate ozone contact times to be 3 to 5 times higher than that required for Giardia; however, studies also indicate chlorine is not feasible for Cryptosporidium inactivation. The chance of a disease outbreak from Cryptosporidium here is much less due to the GVRD's closed watersheds. The illness in Milwaukee was linked to spring runoff into Lake Michigan, an unprotected water supply, and a degradation of the treatment processes.

If the GVRD stopped logging, would that eliminate the need for water quality improvements?

No. In 1991, an independent panel of experts concluded that the practice of small scale logging does not appear to create water quality problems and stated "Halting of logging in the watersheds would not cause the issue of water quality improvement measures including filtration to be abandoned." Another consultant study in 1993 concluded that GVRD harvesting and road building operations produce practically untraceable amounts of turbidity generating sediment at the water supply intake. They concluded the primary source of sediment, including that which is responsible for turbidity, is from natural erosion originating either in undisturbed areas that have never been logged or from streambank and reservoir delta deposits that are unrelated to the current forest practices in the watershed.

The water already smells of chlorine. Won't adding more make the water taste worse?

If rechlorination is selected as the secondary disinfectant it will taste more chlorinous. If chloramine is used, the water will have less of a chlorinous taste then it does presently.

I have heard that chloraminated water spills will kill all the fish in the Fraser River. Is this true?

No, this is not true. This concern was addressed by the environmental consultant in the Stage III EIA report who stated:

While there may be some impacts to salmon resources in the Lower Mainland, the use of chloramine as a secondary disinfectant will in no way jeopardize the entire Fraser River fishery. A spill of chloraminated water would be a localized event that in most cases would not last more than a few hours. Although a severe spill could kill most of the

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fish in a small tributary, this loss would represent only a small fraction of the total Fraser River salmon population. In the worst case, chronic discharges of chlorine residuals via stormwater outfalls might reduce the productivity of streams over a wide area. However, the Lower Mainland supports only 2% of the total Fraser River salmon runs. Thus, even the worst case would not jeopardize the entire fishery.

If chloramine kills fish, how can it be safe for humans?

Both chloramine and chlorine react with fish gill tissue and prevent the transfer of oxygen from the water to their blood stream causing them to suffocate. This does not apply for humans breathing air or drinking water. Chloramine is used by about 25 percent of the larger cities in North America, some for over 75 years. Ottawa, for example, just converted to chloramine in 1992; Victoria has been using it for 50 years.

If chloramine is so stable, does it ever break down?

Yes. Chloramine breaks down on contact with "oxidizable material" such as sewage, dirt, and organic material, and larger water volumes and so depending on the circumstance, it will break down in either a few minutes or up to a few days. It breaks down to ammonia and chloride - both are natural to the environment.

Do chlorine and chloramine cause cancer?

There is no evidence indicating that chlorine or chloramine are carcinogenic at concentrations typically used in drinking water distribution systems. The combination of chlorine and natural organics in the water combine to form compounds known as disinfection by-products, which have been linked, using high doses, to cancer in laboratory animals, thus indicating a possible low risk to humans. Chloramine produces significantly lower levels of disinfection by-products than chlorine does. Acceptable levels for disinfection by-products are established by the health authorities in the Canadian Drinking Water Quality Guidelines.

Why are we concerned over adequacy of water supply when it rains so much of the time?

Most of the rain falls during the fall-winter-spring period when public demand for water is lowest. We have only limited capacity to store that

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water for higher demand periods. In summer, the demand can readily soar to double the winter level and strain our limited storage reserves.

Why not implement water conservation instead of increasing supply capacity?

More active water conservation is one of the GVRD's priorities, and is necessary to help minimize the cost of providing service; however, with the predicted rate of growth of the population in this region, even the most effective conservation program will only serve to delay the need for major supply improvements for 5 to 7 years. A new source of supply will be needed soon, and given the planning and construction time required, a decision must be made shortly.

Why can't GVRO use the water from Coquitlam Lake after B.C. Hydro has generated power with it?

The water used by B.C. Hydro is discharged from their power plant directly to the ocean, in Indian Arm. It is not feasible to convey the water from this low elevation point to the GVRD's higher pressure water system. It could be done, but pumping would be required and would use more energy than that generated by passing the same amount of water through B.C. Hydro's turbines.

How strong an earthquake is expected in the Lower Mainland?

The most likely source for an earthquake which would affect the Lower Mainland is the subduction zone off the west coast of Vancouver Island where one slab of the earth's crust is trying to slide underneath another. This zone was the subject of many recent reports in the local media. The predicted magnitude 8.0+ earthquake in this zone would produce ground motions and shaking effects throughout the Lower Mainland similar to that experienced in San Francisco during the October 1989 earthquake. According to the experts, this event is likely to occur once every 475 years.

A less likely source is one of the many currently inactive faults in the Greater Vancouver area. A magnitude 6.5 earthquake on one of these faults would produce much more powerful shaking, equal to or perhaps exceeding that felt in Los Angeles during the January 1994 earthquake. The approximate likelihood of this event occurring is less than once in 2000 years.

Q-5


What size earthquake can the current Seymour Falls Dam withstand?

If the Seymour Falls Dam site was subjected to earthquake generated ground motions and shaking similar to that felt in San Francisco and Los Angeles during those recent earthquakes, the dam would likely suffer severe damage. It can, however, safely withstand less severe ground motions and shaking, up to and including an earthquake which likely occur once every 300 years.

Q-6

-

Terms

Glossary of Terms and Abbreviations


Bacterial regrowth - the growth of bacteria in a water distribution system after initial disinfection.

B.C. Health Act - governs the operation of most waterworks systems in British Columbia under the jurisdiction of the Ministry of Health.

British Columbia Safe Drinking Water Regulation - established by the B.C. Ministry of Health in 1992, the B.C. Safe Drinking Water Regulation essentially makes the Canadian Drinking Water Quality Guidelines for fecal and total coliform bacteria a legal, enforceable standard in B.C.

Canadian Drinking Water Quality Guidelines - published by Health Canada, they are used by water utilities in Canada as the standard to meet. The B.C. Ministry of Health uses the Guidelines to judge the quality of water provided by various waterworks systems.

Carcinogen - a cancer causing substance.

Chloramine - compound of organic or inorganic nitrogen ammonia and chlorine at low concentrations in water.

Chlorination - the application of chlorine or chlorine compounds at low concentrations to water, generally for the purpose of disinfection.

Disinfection By-Products (DBPs) - compounds formed when a chemical disinfectant (e.g. chlorine) reacts with organic compounds in water. DBPs referred to in this report are Trihalomethanes and Haloacetic Acids.

Filtration - water treatment process for the removal of particulate matter. Granular media beds using sand or other granular materials are commonly used. Direct filtration is a filtration process without presettling of particulate matter from the water.

Giardia - an organism that may be carried by animals and humans. Giardia may be found in many surface waters and causes a waterborne disease called giardiasis (beaver fever).

Haloacetic Acids (HAA) - group of disinfection by-products identified as low risk carcinogens.

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Medical Health Officers - are empowered by the B.C. Safe Drinking Water Regulation to require improvements to bring the water into compliance with the microbiological standards for potable water.

Micrograms per litre (JlgIL) - a measurement of concentration in water, essentially equal to parts per billion (ppb). One ppb is comparable to one second in 32 years(11,600 days).

Milligrams per litre (mgIL) - a measurement of concentration in water, essentially equal to parts per million (ppm). One ppm is comparable to one second in 11.6 days.

ML/day - a measurement of water flow, in millions of litres per day.

Nephelometric Turbidity Unit (NTU) - measurement unit for turbidity.

Ozone - unstable gas generated on-site by high voltage electrical discharges through air or oxygen gas. Injected into the water, ozone is highly effective against viruses, bacteria and parasites.

Pathogens - disease causing microorganisms (bacteria, viruses and parasites).

Potassium permanganate - a strong oxidant which imparts a pink colour to the water.

Primary disinfection - initial disinfection of a water supply.

Secondary disinfection - provision of a disinfectant residual in a water distribution system through redisinfection or stabilization of the primary disinfectant.

Trihalomethanes (THMs) - a specific group of DBPs. Research has indicated a very low level of carcinogenic risk to humans from ingesting THMs in drinking water. A limit for the level of THMs in drinking water has been set in the Guidelinesfor Canadian Drinking Water Quality.

Turbidity - a cloudy condition in water caused by the presence of suspended matter, resulting in the scattering and absorption of light.

Ultraviolet light - biocidal radiation provided by low pressure mercury vapour lamps used for disinfection of drinking water.

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Abbreviations


DBE - Design Basis Earthquake

DFO - Department of Fisheries and Oceans

DWQIP - Drinking Water Quality Improvement Plan

EIA - Environmental Impact Assessment

GVRD - Greater Vancouver Regional District

GVWD - Greater Vancouver Water District

HAAs - Haloacetic acids

MAC - Maximum acceptable concentration

MCE - Maximum Credible Earthquake

MHOs - Medical Health Officers

ML/day - million litres per day (megalitres per day)

MOE - Ministry of Environment

NPV - net present value

ppb - parts per billion

ppm - parts per million

THMs - trihalomethanes

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List of Reports

List of Reports

Analysis of Anticipated Foundation Settlements, Seymour Falls Dam, M.Sc. Thesis, by D.B. Campbell, University of Illinois (May 1960).

Seymour Falls Dam, Volume I, Record of Design; report to GVWD, by Crippen Wright Engineering Ltd. (August 1962).

Seymour Falls Dam, Volume II, Record of Construction; report to GVWD, by Crippen Wright Engineering Ltd. (May 1963).

Seismicity and Dam Design; Bulletin 46. International Commission on Large Dams (ICOLD) (1983).

Preliminary Report on the Status of Water Quality in the Metropolitan Vancouver Area, by the Water Quality Technical Committee (May 1986).

Evaluation of Region's Drinking Water Quality and Treatment Procedures, by Economic and Engineering Services, Inc. (July 1987).

Seymour Falls Dam: Supporting Documents for Operation and Maintenance Manual, Hydrologic and Hydraulic Aspects; report to GVWD, by Klohn LeonoffLtd. (August 1987).

The Use of Penetration Tests to Determine the Cyclic Loading Resistance of Gravelly Soils During Earthquake Shaking; Ph.D. Thesis, Department of Civil Engineering, University of California, Berkeley by L.F. Harder (1988).

Cleveland Dam: Proposed Modifications to Pass the Probable Maximum Flood, Preliminary Design; Appendix I (Tailwater Studies at Cleveland Dam and Seymour Falls Dam); report to GVWD, by Klohn Leonoff Ltd. (December 1989).

Summary Report on Watershed Hydrology Analysis, by Kerr Wood Leidal Associates Limited (December 1989).

National Building Code of Canada, National Research Council, Ottawa, and Supplement to the National Building Code of Canada (1990).

Drinking Water Quality Improvement Plan, Final Secondary Disinfection Report, by Economic and Engineering Services, Inc. (March 1990).

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List of Reports

Drinking Water Quality Improvement Plan, Final Primary Disinfection Report, by Economic and Engineering Services, Inc. (April 1990).

Report on Ultimate Potential of Existing Watersheds, by Kerr Wood Leidal Associates Limited (April 1990).

Seymour Falls Dam, Stability Analysis, Phase I, Volumes I and II; report to GVWD, by Klohn-Crippen Consultants Ltd. (KCCL) (July 1990).

Drinking Water Quality Improvement Plan, Final Summary Report, by Economic and Engineering Services, Inc. (September 1990).

Seismic Hazard Review Study for Cleveland and Seymour Falls Dams, British Columbia, Canada; final report to Greater Vancouver Regional District, Job No. 20819-002-004 by Dames and Moore (February 1991).

Seymour Falls Dam, Stability Assessment, Phase II; report to GVWD, by Klohn-Crippen Consultants Ltd. (KCCL) in association with BCHIL (May 1991).

Cleveland and Seymour Falls Dam: Stability Assessment, Phase III Design Basis Memorandum; report to GVWD, by Klohn-Crippen Consultants Ltd. (KCCL) (August 1991).

Watershed Management Evaluation and Policy Review, Final Summary Report, by Economic and Engineering Services, Inc. et al. (August 1991).

Seymour Falls Dam Stability Assessment - Phase III Design Report (Draft), by Klohn-Crippen Consultants Ltd. (KCCL) (September 1991).

Seymour Falls Dam Site Development Options (Draft No.2), by KlohnCrippen Consultants Ltd. (KCCL) (November 1991).

Seymour Falls Dam Earthworks - Phase III Engineering, Start-Up Memorandum (Draft), by Klohn-Crippen Consultants Ltd. (KCCL) (August 1992).

Environment Impact Assessment of Proposed Secondary Disinfection of Drinking Water, Baseline (Stage I) Report, by Norecol Environmental Consultants, Inc. and Dayton & Knight Ltd. (December 1992).

Discussion Paper, Seymour System Hydraulics, by Kerr Wood Leidal Associates Limited (Draft, January 1993).

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List of Reports

Assessment of Turbidity-Generating Sediment Sources and Transport in the Capilano, Seymour and Coquitlam Watersheds, by Thurber Engineering Ltd. (March 1993).

Discussion Paper, Capilano System Hydraulics, by Kerr Wood Leidal Associates Ltd. (March 1993).

Environmental Impact Assessment of Proposed Secondary Disinfection of Drinking Water, Stage II Report, by Norecol Environmental Consultants, Inc. and Dayton & Knight Ltd. (May 1993).

Technical Memorandum: Estimate of Rechlorination Stations III the GVWD Service Area (staff report) (May 1993)

Technical Memorandum: Mechanical Cleaning (Pigging) Water Mains (staff report) (May 1993)

Capilano and Seymour Water Filtration Pilot Study, Volumes 1 and 2, by SCBV Consultants, Inc. (June 1993)

Disinfection and Corrosion Control Predesign Report, Volumes 1 to 4 and Process Design Criteria Report, by SCBV Consultants, Inc. (June 1993)

Predesign and Planning Studies for Drinking Water Quality Improvement Plan, Draft Site Selection Report, by SCBV Consultants, Inc. (June 1993)

Summary Report, Predesign and Planning Studies, by SCBV Consultants, Inc. (June 1993)

Water Filtration Plant Planning Report, by SCBV Consultants, Inc. (June 1993)

Status of Predesign and Planning Studies for the Drinking Water Quality Improvement Facilities (staff report to the GVRD Administration Board) (July 1993)

Seymour Falls Dam, Stability Assessment - Phase ill, Interim Design Report (Draft); report prepared for GVWD, by Klohn-Crippen Consultants Ltd. (KCCL) (September 1993).

Design Basis Memorandum, Revision 1 (Draft); report prepared for GVWD, by Klohn-Crippen Consultants Ltd. (KCCL) (September 1993).

Technical Memorandum: Analysis of Recent Turbidity Records Relative to the Drinking Water Quality Improvement Plan (staff report) (October 1993)

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List of Reports

Summary Report, Environmental Impact Assessment of Proposed Secondary Disinfection of Drinking Water, Stage III Report, by Norecol Dames & Moore Inc. (November 1993)

Technical Memorandum: Evaluation of Future Supply Alternatives, StafflEconomic and Engineering Services report (November 1993)

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