Onondaga County CSO Program:Gray-Green Infrastructure

Harbor Brook CSO 018 Constructed Wetlands Pilot Treatment SystemJoanne M. Mahoney, County Executive

Prepared for:

Onondaga County, Syracuse, New YorkPrepared by:

March 2011

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Project LocationThe project is located along Harbor Brook on County property just south of Burnet Park on the west side of Syracuse near the Skunk City neighborhood.

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Existing Site

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Site Enhancement Ultimate Vision

▫ Wetland treatment of CSO 018

▫ Grit and floatables removal of CSO 018

▫ Improved water quality in Harbor Brook

▫ Community park▫ Educational

resource

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First Step to Site Enhancement

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Design and construction of a 2 acre full scale pilot treatment wetland system along Harbor Brook at Combined Sewer Overflow (CSO) 018. VELASKO ROAD

Conceptual Rendering

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Three types of wetlands will be constructed for pilot testing: Floating Wetland Island, Vertical Downflow, and Surface Flow.

Pilot Treatment Wetlands System

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Floating Wetland Island▫ Vegetation mats

planted with diversity of native species

▫ Mats float on water surface with roots in water column

▫ Provides high storage volume without inundating plants

▫ High habitat value▫ Low mosquito

productivity

Floating Wetland Islands

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Pilot Treatment Wetlands System

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Vertical Downflow Wetland

▫ Flow is dosed and distributed across surface to percolate through gravel bed

▫ Planted with robust native species to tolerate flooding and draining

▫ No open water and no mosquito productivity

Vertical Downflow Wetlands

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Pilot Treatment Wetlands System

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Surface Flow Wetland▫ Most closely

resembles a natural wetland of robust native species

▫ Vegetated shelf and deep water zones to redistribute and aerate

▫ Medium to high storage volume

▫ High habitat value▫ Low mosquito

productivity▫ Relatively low cost

Surface Flow Wetland

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CSO 018 Treatment Overview

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Pilot Operations - Series Flow

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Pilot Operations - Parallel Flow

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Pilot Operations – Series & Parallel

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Pilot Treatment System Benefits•Pilot system will provide immediate water

quality improvements:▫Grit and floatables (onsite at-grade

structure)▫Bacteria▫Nutrients (nitrogen and phosphorus)▫Total suspended solids and BOD5

•Recommendation from pilot will result in a final permanent wetland treatment system

•Designed for 1-year, 2-hour storm event, but higher flows and volumes could be accepted

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Permits and Approvals Required• SPDES Permit Modification for CSO 018 – NYSDEC• Article 15 Permit Modification Protection of Waters –

NYSDEC• Section 401 Water Quality Certification – NYSDEC• SPDES General Construction Permit – NYSDEC• Nationwide Permit No.7 Outfall Structures – USACE• Nationwide Permit No.43 Stormwater Mgmt. Facilities –

USACE• Coordination with NYS Natural Heritage, U.S. Fish &

Wildlife Service, and NYS Office of Parks, Recreation and Historic Preservation

• OCDWEP – fill and compensatory storage • City of Syracuse Site Preparation Permit (10,000 SF

threshold)• City of Syracuse Curb-cut Permit (access to grit &

floatables facility)

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Stakeholder Outreach• City of Syracuse

▫ Dept of Engineering▫ Bureau of Planning and

Sustainability▫ Dept of Public Works▫ Dept of Parks and

Recreation▫ Div of Code Enforcement

• New York State Agencies▫ Dept of Environmental

Conservation▫ Dept of Transportation

• Federal Agencies▫ U.S. Army Corps of

Engineers▫ Federal Emergency

Management Agency▫ USGS (gauging station)

• Organizations and Not-for-profit Groups▫ Atlantic States Legal

Foundation, Inc.▫ Onondaga Environmental

Institute▫ Onondaga Nation▫ Westside TNT

Neighborhood

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Stakeholder Outreach• Organizations and Not-for-

profit Groups, continued▫ Syracuse United

Neighbors Westside Coalition

▫ Partnership for Onondaga Creek

▫ Syracuse Parks Conservancy

▫ Syracuse Chargers Rugby Club

▫ Catholic Charities

• Other Municipalities▫ Town of Geddes

Supervisor

• Schedule▫ March 18 City/County

Meeting presentation▫ April 7 meeting with

Mayor and County Executive

▫ Correspondence and consultation as needed

▫ Presentation to community group leaders in mid-April

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Project Schedule

•Design and stakeholder outreach is underway

•Permit submittals and regulatory approvals are critical for schedule

•Construction is targeted for 2011•2 year monitoring period•Planning and design for final wetland

treatment system and site enhancement can begin during monitoring period

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Questions and Discussion

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