LTCP meeting 11-18-04

Ottawa River Public Meeting Long Term Combined Sewer Overflow Control Plan Input November 18, 2004

Discussion Agenda
Program Overview
Combined Sewer Overflows in Ottawa River
Identification of Alternative Types
Potential Siting of Control Facilities
Opportunity for Input

CSO 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 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 Area

Ottawa River Overflow Frequency 13 67 14 65 21 64 2 63 25 62 12 61 Annual Frequency Outfall

Ottawa River Overflow Volume 6.1 67 5.3 65 39.9 64 0.2 63 52 62 2.5 61 Annual Volume (MG) Outfall

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

CSO 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 Information
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 Facilities Storage alternatives can be below grade as basins or tunnels. Generally some access hatches or support structures are present.

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

Treatment Facility Basic Information
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 and 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 Facilities Three large treatment facilities in the Detroit Area. These facilities generally require a fairly large building.

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

Flow Reduction / Rerouting Pros 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 / Rerouting Photos

EPA 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 – probable storage/ treatment

Ottawa River Evaluation – probable sewer separation

Siting 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 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 Sites

Ottawa River Potential Sites –Joe E. Brown Park

Ottawa River Potential Sites - Jeep

Ottawa River Potential Sites – Central Ave.

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

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

Treatment Sizing Required Treatment Rate and Untreated Overflow Frequency – Ottawa River; CSO 61, 62, 63, 65, 67 1.3 MG 2 MG

Impact on Footprint

Cost projections
Cost projections are under development

Evaluations 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 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.

LTCP meeting 11-18-04

by HartTWI on Aug 04, 2010

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LTCP meeting 11-18-04 — Presentation Transcript