ltcp meeting 11-18-04

Ottawa River Public Meeting Ottawa River Public Meeting

Long Term Combined Sewer Overflow Control Plan Input

November 18, 2004

Discussion AgendaDiscussion Agenda

• Program Overview

• Combined Sewer Overflows in Ottawa River

• Identification of Alternative Types

• Potential Siting of Control Facilities

• Opportunity for Input

CSO Control PlanningCSO Control Planning

• The City must control CSO discharges according to the consent decree

• Alternatives are being evaluated with respect to their feasibility, associated benefits and costs

• Public input on alternatives considered is sought in tonight’s meeting

Project TimelineProject Timeline

• The Long Term Control Plan Document is scheduled to be submitted to USEPA in July 2005

• A review and modification period will follow the plan submittal

• The work identified in the plan is to be completed by August 31, 2015

Ottawa River Combined Ottawa River Combined AreaArea

Ottawa River Overflow Ottawa River Overflow FrequencyFrequency

Outfall Annual Frequency

61 12

62 25

63 2

64 21

65 14

67 13

Ottawa River Overflow Ottawa River Overflow VolumeVolume

Outfall Annual Volume (MG)

61 2.5

62 52

63 0.2

64 39.9

65 5.3

67 6.1

Type of AlternativesType of Alternatives

• Alternative selection is a combination of performance and suitability considerations. There are a number of types of alternatives.

CSO Control OptionsCSO Control Options

• There are three basic control options• Storage (holds excess flow until capacity is

available)• Treatment (cleans flow before it is discharged –

disinfects and removes pollutants)• Separation (provides new sanitary or storm

sewers so that combined sewers are eliminated)• Flow reduction/ rerouting can enhance the

above options

Storage Basin Facility Basic Storage Basin Facility Basic InformationInformation

• Type of facility: concrete tank either concealed or visible

• Land area required: 3 – 10 acres

• Typical siting locations: waterfront property, parks, other vacant parcels near rivers

• Other requirements: some sewer work to bring flow to the site; building for support functions

Basin Storage FacilitiesBasin Storage FacilitiesStorage alternatives can be below grade as basins or Storage alternatives can be below grade as basins or tunnels. Generally some access hatches or support tunnels. Generally some access hatches or support structures are present.structures are present.

Storage Basin Facilities -Storage Basin Facilities -Pros and ConsPros and Cons• Pros

• Most work is limited to one location and the adjacent areas are not disturbed

• Volume and frequency of discharge to the river is reduced • Site can be designed to be aesthetically pleasing

• Cons• Use of land for other activities is limited• Construction activities are generally 2 – 3 years in duration

limiting the use of sites during that period.• A building is required for support facilities• Some untreated overflow will remain.

Storage Tunnel Basic Storage Tunnel Basic InformationInformation

• Type of facility: below ground tunnel• Land area required: limited land requirements –

most work is along a linear corridor and is not visible from the surface.

• Typical siting locations: about 60 – 75 feet below grade; linear corridors (such as streets)

• Other requirements: drop shafts and discharge points with pump stations and control of floatables

Storage Tunnel Facilities Storage Tunnel Facilities Pros and ConsPros and Cons

• Pros• Most work is performed underground and at construction

shaft locations, minimizing land needs

• Volume and frequency of discharge to the river is reduced

• Toledo has successfully constructed similar projects

• Cons• Difficult to clean and access

• Some untreated overflow will remain.

• A building would be required to house support facilities

Storage TunnelsStorage Tunnels

Storage tunnels primarily consist of large Storage tunnels primarily consist of large underground pipes 12 – 15 feet in diameter. underground pipes 12 – 15 feet in diameter. There are additional support structures that There are additional support structures that would be located at the end of the tunnel.would be located at the end of the tunnel.

Treatment Facility Basic Treatment Facility Basic InformationInformation

• Type of facility: smaller concrete tank with screening and disinfection capability

• Land area required: 2-5 acres

• Typical siting locations: waterfront property, parks, other vacant parcels near rivers

• Other requirements: some sewer work to bring flow to the site; above ground building to house equipment

Treatment Facilities Pros Treatment Facilities Pros and Consand Cons• Pros

• Most work is limited to one location and the adjacent areas are not disturbed. Facility footprint is smaller than storage facility.

• Small storms are stored. Larger storms discharge partially treated water.

• Water that goes to the river has been treated for bacteria.• Cons

• Treatment generally requires construction of a good size building, this building is larger than required for a storage only alternative due to more equipment.

• Facility is more complex to operate and maintain than a storage only basin.

Treatment FacilitiesTreatment Facilities

Three large treatment facilities in the Detroit Three large treatment facilities in the Detroit Area. These facilities generally require a Area. These facilities generally require a fairly large building.fairly large building.

Sewer Separation BasicsSewer Separation Basics

• Constructs a new sewer to separate flow

• Generally requires 3 – 6 months to complete work on a street; 1 – 2 years to complete work in an areas

• Generally doesn’t involve land acquisition

Sewer Separation Pros and Sewer Separation Pros and ConsCons

• Pros• Upgrades the sewer system

• Eliminates CSO discharges

• Minimal property requirements

• Cons• May increase total amount of pollutants to the

waterways• Disruptive to individual property owner

Sewer SeparationSewer Separation

Sewer separation requires construction of new Sewer separation requires construction of new sewers in areas where a single pipe system existssewers in areas where a single pipe system exists

Flow Reduction / Rerouting Flow Reduction / Rerouting Pros and ConsPros and Cons

• Pros• Addresses problem at the source

• Could be considered best environmentally

• Could reduce basement or surface flooding

• Cons• Generally not adequate to solve the entire

problem• Most disruptive to individual property owner• Administratively intensive program

Flow Reduction / Flow Reduction / Rerouting PhotosRerouting Photos

EPA CriteriaEPA Criteria

• The primary concern in other CSO Plans around the country is the frequency at which CSO’s discharge

• The control of bacteria of bacteria is important

• Other items of concern• Volume of discharge• Pollutants in discharge• Measureable impacts on waterways

Ottawa River Evaluation – Ottawa River Evaluation – probable storage/ treatmentprobable storage/ treatment

Ottawa River Evaluation – Ottawa River Evaluation – probable sewer separationprobable sewer separation

Siting Issues/ ConcernsSiting Issues/ Concerns

• Consider• Areas of open space (sites), reasonably close to

outfalls• Current use of existing sites & associated impacts

due to construction or long term use• Ownership of sites• “Fatal flaws” such as environmental or geotechnical

issues.• Opportunities for secondary benefit – e.g.

brownfield reuse, coordination with other projects.

Ottawa River Potential SitesOttawa River Potential Sites

• Potential sites• Potential sites have been identified based on location

of open space• Currently evaluating the feasibility of these sites• No decisions have been made about the use or non

use of any site

Ottawa River Potential SitesOttawa River Potential Sites

Ottawa River Potential Sites Ottawa River Potential Sites –Joe E. Brown Park–Joe E. Brown Park

Ottawa River Potential Sites Ottawa River Potential Sites - Jeep- Jeep

Ottawa River Potential Sites Ottawa River Potential Sites – Central Ave.– Central Ave.

Ottawa River Potential Sites Ottawa River Potential Sites – Willy’s Park & Liberty Park– Willy’s Park & Liberty Park

Storage Sizing RequiredStorage Sizing Required

Comparison of Joe E. Brown & Jeep Facilities: 1998 results

01

2

455

1112

01

3

56

0

10

20

30

40

50

60

70

80

0.0 5.0 10.0 15.0 20.0 25.0 30.0 35.0

storage basin volume (MG)

volume of overflow (MGal)

0

2

4

6

8

10

12

14

16

number of occurrences

Joe E. Brown Jeep Joe E. Brown Jeep

Comparison of Joe E. Brown & Jeep Facilities: 5-Year Results

0

1.8

3.6

7

12

13.4

0.21

2.4

4.4

8.4

0

10

20

30

40

50

60

70

80

0.0 5.0 10.0 15.0 20.0 25.0 30.0 35.0

storage basin volume (MG)

average annual volume of

overflow (MGal)

0

2

4

6

8

10

12

14

16

average number of occurrences per year

Joe E. Brown Jeep Joe E. Brown Jeep

Storage Size and Overflow Frequency – Ottawa Storage Size and Overflow Frequency – Ottawa River; CSO 61, 62, 63, 65, 67River; CSO 61, 62, 63, 65, 67

Treatment Sizing RequiredTreatment Sizing Required

11.4

9.2

7.06.2

4.83.6 3.0

2.01.2 0.8 0.8 0.8 0.8

0

5

10

15

20

25

30

50 60 70 80 90 100 110 120 130 140 150 160 170

treatment capacity (cfs)

volume of untreated overflow

(MGal)

0

4

8

12

16

20

24

number of occurrences

volume # of events

Treatment Rate and Treatment Rate and UntreatedUntreated Overflow Frequency – Overflow Frequency – Ottawa River; CSO 61, 62, 63, 65, 67Ottawa River; CSO 61, 62, 63, 65, 67

1.3 MG1.3 MG 2 MG2 MG

Impact on FootprintImpact on Footprint

Cost projectionsCost projections• Cost projections are under development

Cost vs Overflow EventsOttawa River - Storage Alternative 61, 62, 63, 65, 67

0

5

10

15

20

25

30

Construction Cost

Number of Untreated Overflows

Treatment Basin Storage Basins Tunnel Storage

Evaluations Are ContinuingEvaluations Are Continuing

• Additional cost development and comparison to benefits are ongoing

• Better definition of potential sites and discussions with property owners/ operators

• More technical evaluations (will support cost assessment)

How you can helpHow you can help

• Provide feedback on the alternative types through the various stations. Let us know what you like and don’t like and the type of alternative.

• Give us feedback on the potential sites.

• Provide other comments on what is important to you.

• Ask questions at the various station locations.