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Plan

Stormwater Pollution Prevention Plan (Rev. 6) Derwent Way Soil Transfer and Barge Facility

i Project 12943 / November 2017

PREFACE

This Stormwater Pollution Prevention Plan is designed to conform to the Port Metro Vancouver’s July 2015 Project and Environmental Review Guidelines: Developing Your Stormwater Pollution Prevention Plan in support of the conditions outlined in the Project & Environmental Review (PER No. 16-022) Application Submission Requirements dated February 16, 2015. Revision 6 addresses comments provided by the Vancouver Fraser Port Authority (VFPA) and third-party technical reviewers in September 2017, and incorporates the 90% design drawings for the facility, issued in October/November 2017.

The Barge Loading Facility is a transfer facility for soils that have concentrations less than BC Hazardous Waste Regulation criteria. The transfer station facilitates delivery of contaminated soil to soil treatment facilities in the Lower Mainland and Fraser Valley.

Trucks bring soil to the facility where it is temporarily stored before being transferred to a barge for transport to an approved treatment facility in Mission BC.

Summit Earthworks Inc. (Summit) minimizes any possible impact of its operations by utilizing best available control technologies and operating procedures.

The purpose of this document is to provide stormwater management planning in conjunction with overall site planning, design, and future construction, beginning at the outset of the Project (operation of a Barge Loading Facility at this location by Summit Earthworks Inc.).

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Rev. 6) Facility

r 2017

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iv Project 12943 / November 2017

LIST OF APPENDICES

Appendix A Site Drainage Plan Appendix B Infiltration System Design Appendix C Stormwater Design Calculations

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Project 12

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2943 / November

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Project 12

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2943 / November

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3 Project 12943 / November 2017

The Waste Storage Area (refer to Drawing No. 17-12943-01) will be contained by lock-block walls and a high-density polyethylene (HDPE) liner, and covered with a parabolic roof to prevent the majority of precipitation during heavy storm events from coming into contact with the soils temporarily stored on Site. This roof covers the Waste Storage Area and the road immediately south of the Waste Storage Area, minimizing stormwater contact with the stored material and the area before the truck wash where contaminated soils could potentially be tracked. Stormwater and runoff that is generated inside the Waste Storage Area will be collected in a collection sump that will flow by gravity to a pumping station to be pumped to the water storage tank and treatment system. Roof runoff will not come into contact with the stored material, and will infiltrate to the ground via underground infiltration pits to the north and south of the Waste Storage Area.

The Gravel Storage Bays (refer to Drawing No. 17-12943-01) are contained with berms. Water from this area will percolate into the soil or drain to ditches/swales to the north.

The Barge Ramp Area (refer to Drawing No. 17-12943-01) is comprised of the sloped area down to the barge ramp. The runoff in this area will flow to a separate small sump and will be pumped to the water storage tank and treatment system.

The Site area outside of these three areas is referred to as the Remaining Site Area. It is noted that this area contains several small sub-catchments (the small asphalt road area at the northernmost edge of the site that drains northwards, the asphalt road area along the western edge of the Site that drains to ditches/swales to the east, and the unpaved areas surrounding the Gravel Storage Bays and Waste Storage Areas that drains to ditches/swales to the north). These sub-catchments within the Remaining Site Area do not experience traffic from trucks that have recently unloaded soils or entered the Waste Storage Area without having passed through the Wheel Wash. Trucks that move through this area will be exiting with washed wheels or will be entering the Site with ‘clean’ wheels. Site areas excluded by the offset buffer zones (from the railway right-of-way to the west, and the Fraser River to the south) were also included in the Remaining Site Area as they will similarly not experience any traffic or materials impacts from Project operations, and pose a low risk for pollutant entrainment into stormwater.

The Waste Storage Area and Barge Ramp Area have the potential to generate a higher concentration of solids and contaminant runoff while soil is being loaded and/or unloaded during a storm event. Following Port Metro Vancouver’s July 2015 Project and Environmental Review Guidelines: Developing Your Stormwater Pollution Prevention Plan, SPPPs should address two types of rainfall events: Water Quality Events and Storm Drainage Events. Runoff as a result of the first rain after a dry period mobilizes a greater concentration of contaminants in a short period of time. This initial surface water runoff is known as the “first flush” and represents a Water Quality Event. A Storm Drainage Event is defined as a design storm event used to size on Site infrastructure and environmental responses – in this case, storage tank, pumps, treatment system capacity, and containment berms.

Water Quality Events represent small, frequent events, but are large enough as to account for the majority of annual stormwater generated on Site. The “first flush” design event selected as the design basis for this SPPP is a 1-in-2 year storm event. Several mitigation strategies (described further in the sections below) are utilized to address Water Quality Events in this



SPPP. These strategies minimize excess generation of stormwater in areas of concern, and contain and treat runoff from areas where stormwater may come into contact contaminated soils. This minimizes the concentrations of contaminants in runoff and reduces the impact of sediment-laden or contaminant-laden runoff from the “first flush.”

As this Site is relatively small but will temporarily store contaminated materials and occasionally experience elevated volumes of traffic (up to 60 trucks per day, as well as traffic from on Site equipment), this SPPP focusses on addressing Water Quality Events with elevated contaminant levels. Flooding or overflow events are expected to be less of a concern at this relatively small, flat Site with limited up-gradient stormwater inputs.

Storm Drainage Events are mitigated by selecting an appropriate design frequency to develop a stormwater system that can manage variable storm runoff rates and volumes. Design frequencies must be appropriate for the type of structures in question, and should consider the impacts and risk factors associated with flooding or overflow or bypass. The proposed stormwater system at this Site falls under “Minor Systems” listed in the City of New Westminster’s Design Criteria; therefore a 1-in-10 year design storm is sufficient design frequency. Given the industrial nature of the Site and the proposed Project works involving runoff coming into contact with stored soils, a 1-in-25 year storm event has conservatively been selected as the design basis for this SPPP for sizing of infrastructure.

3.3.1 Waste Storage Area

The following hydrological parameters were used to model hydrological properties of the proposed design with respect to the Waste Storage Area:

Waste Storage Area – 0.202 hectares Impervious area – 100% Average slope – 0.2% Time of concentration – 9 min Metro Vancouver Regional IDF Curve Zone 3

Results above are estimated using the City of New Westminster’s Design Criteria for Stormwater Drainage Systems, which is based on the Rational Method proposed in Port Metro Vancouver’s PER Guidelines for Developing Your Stormwater Pollution Prevention Plan.

As the Waste Storage Area has a roof to cover its entire surface area, it is assumed that only 22% of precipitation comes into contact with the waste material (based on approximate estimates of driving rain as a proportion of rainfall) – the remainder drains off the roof to infiltrate to ground via rock pits.

Waste Storage Area – Stormwater to Collection Sump

The peak flow for the Storm Drainage Event was calculated to determine sizing for pumps, tanks, equipment, and piping. The peak flow for the Water Quality Event was calculated to determine runoff volumes requiring retention and treatment on a regular basis. A peak flow of approximately 2.4 L/s (39 GPM) is expected for the Water Quality Event and a peak flow of



approximately 4.7 L/s (74 GPM) is expected for a Storm Drainage Event. The total first flush volume from the Waste Storage Area is estimated to be 4.7 m3 based on a 1 hour, 1-in-2 year design storm, and 8.9 m3 based on a 1 hour, 1-in-25 year design storm.

Waste Storage Area – Roof Runoff to Infiltration Pits

A peak flow of approximately 8.7 L/s (137 GPM) is expected for the Water Quality Event and a peak flow of approximately 16.6 L/s (262 GPM) is expected for a Storm Drainage Event. The total first flush volume from the Waste Storage Area is estimated to be 16.7 m3 based on a 1 hour, 1-in-2 year design storm, and 31.5 m3 based on a 1 hour, 1-in-25 year design storm.

3.3.2 Gravel Storage Bays

The following hydrological parameters were used to model hydrological properties of the proposed design with respect to the Gravel Storage Bays:

Gravel Storage Bays – 0.030 hectares Impervious area – 0% (storage bays expected to be packed gravel) Average slope – 0.7% Time of concentration – 8 min Metro Vancouver Regional IDF Curve Zone 3

A peak flow of approximately 1.0 L/s (16 GPM) is expected for the Water Quality Event and a peak flow of approximately 1.9 L/s (31 GPM) is expected for a Storm Drainage Event. The total first flush volume from the Gravel Storage Bays is estimated to be 3.2 m3 based on a 1 hour,1-in-2 year design storm, and 6.0 m3 based on a 1 hour, 1-in-25 year design storm.

3.3.3 Barge Ramp Area

The following hydrological parameters were used to model hydrological properties of the proposed design with respect to the Barge Ramp Area:

Barge Ramp Area – 0.005 hectares Impervious area – 100% Average slope – 6.7% Time of concentration – 1 min Metro Vancouver Regional IDF Curve Zone 3

A peak flow of approximately 0.3 L/s (4 GPM) is expected for the Water Quality Event and a peak flow of approximately 0.5 L/s (8 GPM) is expected for a Storm Drainage Event. The total first flush volume from the Barge Ramp Area is estimated to be 0.5 m3 based on a 1 hour, 1-in-2 year design storm, and 1.0 m3 based on a 1 hour, 1-in-25 year design storm.

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Project 12

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4.2 Potential Pollutant Sources

An assessment was conducted to identify materials and practices that may reasonably be expected to add significant levels of pollutants to stormwater or that may result in the discharge of pollutants during dry weather from separate storm sewers draining from the facility. This section will provide a description of potential sources that may contribute to the presence of contaminants in stormwater runoff.

Soil receiving, handling, transferring, storage, and ship loading could result in soil being spilled onto the ground.

Dust from the temporary soil piles could spread across the Site during dry weather periods. Fuel, oil, or coolant from service vehicles or barges could leak due to damage, normal wear

and tear or during fuelling or preventative maintenance.

4.3 Potential Sensitive Receptors

The Fraser River provides habitat for fish and is a potential sensitive receptor.

4.4 Identified Issues

No outstanding issues have been identified at this time. Section 5.1 outlines the management strategy to address prevention, containment, reduction, and treatment measures.

4.5 Identified Pollutant Pathways

Pollutant pathways identified in the preparation of this SPPP include:

1. Runoff coming in contact with soils stored in the Waste Storage Area; 2. Runoff coming in contact with soils tracked outside the Waste Storage Area by trucks

or equipment. 3. Runoff in contact with fuel or oil from equipment maintenance or refuelling.

The Waste Storage will be isolated from the rest of the Site by a 1.5m high concrete curb, lined with an HDPE liner under an asphalt cover. This design will prevent runoff water from this area from infiltrating into the ground and will inhibit the ability of stormwater runoff from either running into or out of the Waste Storage Area via overland flow. The Waste Storage Area will have a roof over the entire containment area (including the asphalt road directly south of the Waste Storage Area, where trucks unload material), to prevent excess precipitation from coming into contact with the stored soils. The roof will drain to the north and south where runoff that has not come into contact with Site soil handling activities and will infiltrate into the ground via rock pits installed along the northern and southern edges of the Waste Storage Area.

Rainfall and snowmelt that is windblown under the roof structure and falls within the Waste Storage Area will be captured by the containment wall and collected in the collection sump. The pumping station will be arranged such that the first flush water from the Waste Storage Area will be captured and pumped to the onsite water storage tank, upstream of the treatment process.



Trucks and site equipment must manoeuvre around the Site in order to move soil to and from the Waste Storage Area. Trucks are expected to enter the Site with ‘clean’ wheels -- construction/excavation sites in Metro Vancouver (typical generating sites for the type of material accepted) would be equipped with a truck wheel wash. Once trucks have offloaded materials to the Waste Storage Area, they must pass through the truck wheel wash before proceeding through the rest of the site to the exit approach. Loaders will be used on Site to move soils from the Waste Storage Area to the barges.

The areas between where the trucks offload and the wheel wash, and also the paths taken by the loaders to move materials onto barges have the potential to contain tracked soils and contaminants from the Waste Storage Area. This area will be covered and contained to minimize stormwater contact with stored soils and prevent water pollution on Site. Catch basins will capture runoff from these areas during storm events, and convey stormwater to the on-Site treatment system. Effluent from the truck wash will also be pumped to the water storage tank.

A 2,500 litre, above-ground storage tank (AST) may be present on Site for fuelling of site equipment. This storage tank will be a double-walled vacuum-monitored tank placed on a concrete pad. The concrete pad will provide an impervious surface for small drips and leaks during filling and refuelling. The tank and concrete pad will be protected with bollards to provide a visual barrier and prevent impact from trucks and on-Site equipment. Engineered drawings will be produced for the tank and the design will be registered with the Petroleum and Allied Petroleum Products Storage Tanks Regulations. Fuelling will be completed at a minimum distance of 30 m from the high water mark.

Water will be conveyed to the water storage tank from the Waste Storage Area Collection Sump and the Barge Ramp Area via the pumping station indicated on Drawing No. 17-12943-01. Water in the storage tank will be treated as described in Section 5.1.3, prior to discharge to ground. The tank is designed to contain the design storm as defined in the design basis. Following the first flush period, surface water runoff generated within the Waste Storage Area Collection Sump and Barge Ramp Area will be directed to the water storage tank and trigger the treatment system to begin operating. Should the tank continue to fill after the first flush period is over (note that the tank is oversized, even for significant storm events), the runoff will by-pass the water treatment system and be transferred directly to the infiltration system for discharge.

The treatment system will continuously treat water from the tank. Even during periods of inactivity on Site or dry periods, stored water will continue to be processed through the treatment system and discharged to allow space to collect stormwater runoff during the next storm event.

Runoff from the Remaining Site Area will be directed to the swales to the east and west of the Site.

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Project 12

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2943 / November

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Trucks arriving on Site are considered ‘clean’ and will travel to the Waste Storage Area on a paved Site road. They will deposit their load in the Waste Storage Area and continue in a clockwise direction on the paved road through the wheel and truck wash station, before exiting the Site.

Trucks returning to pick up gravel at the Gravel Loading Bays will deposit their load in the Waste Storage Area and continue in a clockwise direction on the paved road through the wheel and truck wash station, before passing through the weigh scale. These empty trucks will then return to the Site via the South Site Access, loading gravel at the storage bays The loaded trucks will then be weighed a third time on weigh scale before exiting the Site via the North Entry/Exit.

Gravel will be clean fill brought from off-Site by barge and by truck.

A loader will remain on Site as permanent Site equipment and will be used to move soil from the Waste Storage Area to the barge. The loader will be limited to the Site and will travel between the Waste Storage Area and the barge along the paved road except when it requires refuelling or maintenance, both activities taking place on Site. The quality of the storm water runoff will not be impacted by the loader movement as soils that are lost during transfer from the Waste Storage Area to the barge will be addressed by dry cleaning of Site roadways during dry periods and first flush runoff will be captured by the treatment system.

Stormwater on the ramp to the barge is captured by a collection sump at the base of the ramp and is pumped to the treatment system. The ramp itself will have 7.5 cm high impervious barriers along the edge to prevent stormwater from flowing off the ramp.

The barges used for offloading to receiving facilities will not be covered, but will be sealed. The barge will contain runoff from the soil piles placed on the barge in addition to runoff from the barge loading ramp during storm events. During typical rainfall events, the soil placed within the barge is expected to absorb stormwater and rainfall. Water will be then be removed with the soil upon final disposal. Water may accumulate within the barge during heavy rainfall periods. Accumulated water within the barge will be removed either by a vacuum truck for off-Site disposal, or will be pumped up to the permitted treatment facility at Duncan Avenue, Mission BC for treatment prior to discharge.

The truck unloading area south of the Waste Storage Area will have 30 cm high concrete containment berms to the east and south to prevent excess runoff from exiting the site. These berms provide containment of the areas experiencing truck traffic that has recently unloaded contaminated soils.

5.1.3 Treatment

One 19,000 litre (5,000 gallon) water storage tank will be required on Site in order to provide sufficient storage for the first flush runoff volume from the Waste Storage Area and Barge Ramp Area as described above. The tank will be designed to manage the entirety of storm water generated during a 1 hour, 1-in-25 year storm event, with additional capacity to manage wash water from the on-site truck and wheel washing station, if necessary. One tank provides a total of 19 m3 of equalization and storage capacity; Storm Drainage Event calculations indicate that 9 m3 are required to contain the entirety of the 1 hour, 1-in-25 year storm event.



Average peak flow rates are expected to be on the order of 2.7 L/s for the Water Quality Event described in the Design Basis. The storage tank will provide storage and equalization prior to the treatment system, such that the treatment system can be sized for lower flows (which will be encountered more often). The treatment system will be designed to treat 2.7 L/s.

First flush water from the Waste Storage Area and Barge Ramp Area will be directed to the water storage tank and continuously processed through the treatment system. As the treatment system is designed for the 2.7 L/s peak flow, the water storage tank can be drained in approximately 2 hours, allowing for additional storage capacity for ongoing rain events. Stormwater will continuously be directed to the storage tank for subsequent treatment during any rain event (Water Quality Event or otherwise) as long as the storage tank has capacity.

Given that the majority of annual rainfall events in Metro Vancouver are below 10 mm/day (Canadian Climate Normals 1981–2010 for Vancouver indicate that, on average, 86% of days with precipitation experience less than or equal to 10 mm/day, and 98% of days with precipitation experience less than 25 mm/day), the storage provided by the storage tank and treatment capacity of the treatment system is considered sufficient, as the design basis accounts for a 22 mm storm occurring in 1 hour.

Stormwater within the water storage tank will be directed to the water treatment system. The system will include solids settling, flocculent injection to enhance settling, sand filtration, and a granular activated carbon filter. Flocculants designed for environmentally sensitive environments (i.e., polymer-based formulations) will be exclusively used. The dose rate and treatment chemical will be adjusted regularly, and will be based on the different contaminants of potential concern associated with each different delivery of soil material to Site. As required, secondary and tertiary treatment of this collected water will be completed until such time as the water is of a suitable quality such that it can be discharged. Effluent water will be tested prior to discharge for the contaminants of potential concern associated with each delivery of soil. The treated water will be discharged to ground via an infiltration system to the north of the Waste Storage Area.

Details of the infiltration system can be found in Drawing No. 17-12943-02, appended to this plan.

Sludge from the treatment process will be collected in by a vacuum truck and disposed of at an accredited soil treatment facility.

Runoff water from the Remaining Site Area will be collected in the swales to the east and west of the property and flow north. The swales will be designed to passively treat or convey the 1-in-25 year peak flow scenario of 26.8 L/s (divided amongst the 2 swales to the east and west), which exceeds design storm flow for this catchment area.

All trucks exiting the Site will go through the truck and wheel wash. The proposed truck and wheel wash model for this facility is Model TW750, capable of 47 L/s (750 GPM), and washing 400 trucks per day. This model includes capacity for two complete tire revolutions as trucks pass through, providing ample space and time for removal of sediments from truck wheels. Water within the wheel and truck wash will be recycled until sediment load becomes significant, or regular maintenance procedures require discharge of the wash water (at a minimum on a daily basis). Discharged wash water will be sent to the water storage tank. Discharge would not

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The water quality of stormwater within the water storage tank will be tested during discharge. Water will be tested for a specific analytical suite (determined by a qualified environmental professional) based on the contaminants of potential concern associated with the soils stored on Site. Each soil load will be delivered with a soil quality report completed by a qualified environmental professional or certified laboratory. The soil quality report will help to determine the analytical suite for the discharge water which will typically include pH, total suspended solids, heavy metals and hydrocarbons. In addition to the chemical composition of the discharge water, visual signs of contamination such as foam, discoloration, sediment or an oily sheen will be assessed.

Discharge would be stopped if parameters exceed the Federal Interim Groundwater Quality Guidelines for Federal Contaminated Sites (FIGQG), CCME surface water guidelines with a 10x dilution, and the BC Contaminated Sites Regulation standards for the protection of drinking water and aquatic life (BC CSR AWFW, DW) for discharge to ground

All weekly and storm event inspections, as well as water quality sampling events will be documented along with repairs/maintenance of the existing stormwater management works and new stormwater management works proposed. The documentation will include the personnel responsible for maintenance or installation and a timeline for completion of the recommended maintenance or installation.

Triggers for substantial replacement or upgrade of the stormwater infrastructure will be as follows:

Discharge analytical results above the applicable standards will trigger recirculation of the effluent through the treatment system, backwash of the sand filters, and replacement of the granular activated carbon.

Treatment chemical levels below 30% will trigger ordering replacement chemicals Heavy sedimentation of the pumping station, catch basins, or collection sump will trigger

cleanout via vacuum truck. At a minimum this will be conducted annually. Erosion or sedimentation of swales will trigger swale upgrade or maintenance within one

month’s notice of the damage. Cracks, leaks, or otherwise failing infrastructure will be replaced upon documentation of

the defects. Good housekeeping practice and BMP enforcement procedures will be developed if these

practices are not followed on three consecutive weekly inspections.

6.3 Adaptive Management and Continuous Improvement

A key process in the effective implementation of the SPPP is the ability to change mitigation measures or actions as site conditions warrant in order to protect stormwater quality. This approach, generally termed as ‘adaptive management’, is a planned and systematic process for continuously improving environmental management practices by learning about their outcomes.

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APPENDIX A

SITE DRAINAGE PLAN

APPENDIX B

INFILTRATION SYSTEM DESIGN

APPENDIX C

STORMWATER DESIGN CALCULATIONS

Catchment Area Area L H s C Tc Event Type Design Storm Volume Duration Intensity* Q Q Q

(m2) (hectares) (m) (m) (%) Weighted (min)

using 1 hour storm

(m3) (mm/hr) (m

3/s) (L/s) (GPM)

Rational Coef.

2,020 0.2020 60 0% 0% 100% 0.1 0.2 0.90 9 Water Quality 1-in-2 year 4.7 10 min 22.0 0.002 2.4 39

2,020 0.2020 60 0% 0% 100% 0.1 0.2 0.90 9 Storm Drainage 1-in-25 year 8.9 10 min 42.0 0.005 4.7 74

50 0.0050 15 0% 0% 100% 1 6.7 0.90 1 Water Quality 1-in-2 year 0.5 10 min 22.0 0.000 0.3 4

50 0.0050 15 0% 0% 100% 1 6.7 0.90 1 Storm Drainage 1-in-25 year 1.0 10 min 42.0 0.001 0.5 8

Water Quality 1-in-2 year 5.2 0.003 2.7 43

Storm Drainage 1-in-25 year 9.9 0.005 5.2 82

2,020 0.2020 60 0% 0% 100% 0.1 0.2 0.90 9 Water Quality 1-in-2 year 16.7 10 min 22.0 0.009 8.7 137

2,020 0.2020 60 0% 0% 100% 0.1 0.2 0.90 9 Storm Drainage 1-in-25 year 31.5 10 min 42.0 0.017 16.6 262



300 0.0300 15 100% 0% 0% 0.1 0.7 0.55 8 Water Quality 1-in-2 year 3.2 10 min 22.0 0.001 1.0 16

300 0.0300 15 100% 0% 0% 0.1 0.7 0.55 8 Storm Drainage 1-in-25 year 6.0 10 min 42.0 0.002 1.9 31

3,730 0.3730 75 35% 30% 35% 2 2.7 0.60 10 Water Quality 1-in-2 year 39.5 15 min 20.7 0.013 12.8 203

3,730 0.3730 75 35% 30% 35% 2 2.7 0.60 10 Storm Drainage 1-in-25 year 74.6 15 min 40.2 0.025 24.9 395





Definitions: L flow path length

H vertical drop from top of watershed to discharge point

s slope

Tc time of concentration

C runoff coefficient

Q runoff flow

Common Rational Equation Runoff Coefficients for Urban Watersheds (ref: TXDOT)

Runoff

coefficient

Runoff

coefficient

0.70-0.95 0.85-0.95

0.30-0.70 0.90-0.95

0.70-0.85

0.30-0.50 0.75-0.95

0.40-0.60 0.75-0.95

0.60-0.75

0.35-0.40 0.30-0.80

0.30-0.70 0.60-0.90

0.10-0.25

0.30-0.40

0.30-0.40

Reference: Standard Handbook of Environmental Engineering

McGraw-Hill 1990

(used for Tc equation, applying FAA formula, and confirming runoff coefficients)

*IDF Curve: MetroVancouver Regional IDF Curve Zone 3

Time of concentration: FAA equation: Tc = G (1.1 - c) L0.5

/ (100 S)1/3

City of New Westminster: Tc follows FAA equation

Tc (lot size ≤2000 m2) = 10 min

Tc (lot size >2000 m2) = 15 min or as calculated

** Waste Storage Area has roof to prevent infiltration of precipitation to the waste material stored within. Conservatively assume 22% of precipitation reaches waste material

based on estimates of driving rain intensity as a proportion of rainfall intensity.

Asphaltic

Streets:

Type of drainage area

Treated Stormwater

Total

Site Stormwater

Total

Waste Storage Area

Roof Runoff**

Infiltrated

Stormwater Total

Ditch/Swale

Stormwater Total

Railroad yards

Playgrounds

Parks, cemeteries

Heavy areas

Light areas

Apartment dwelling areas

Suburban

Multi-units, attached

Multi-units, detached

Single-family areas

Residential:

Neighborhood

Downtown

Business:

Type of drainage area

Industrial:

Roofs

Drives and walks

Brick

Concrete

Barge Ramp Area

Remaining Site

Area

DERWENT WAY BARGE LOADING FACILITY STORMWATER RUNOFF FLOW

November 8, 2017

Keystone Environmental Ltd. Project 12943

Using the Rational Method, City of New Westminster Design Criteria, Port Metro Vancouver PER Guidelines for SPPPs

Gravel Storage

Bays

% Packed

Gravel

% Coarse

Vegetation

% Paved /

Impermeable

Waste Storage Area

Sump**

stormwater pollution prevention plan€¦ · columbia v5g 4g3 g • enginee mwater t way soil t ed...

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