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Spokane River Forum Conference March 26, 2013.  About 1/3 of City  130 outfalls.

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Presentation on theme: "Spokane River Forum Conference March 26, 2013.  About 1/3 of City  130 outfalls."— Presentation transcript:

1 Spokane River Forum Conference March 26, 2013

2  About 1/3 of City  130 outfalls

3 Direct Sewers Raw sewage and stormwater to Spokane River without treatment 1892 Interceptor Sewage to treatment plant and wet weather overflows to Spokane River 1950s Separated Stormwater in separate pipes to River Sewage to plant (no overflows) Infiltrated Treatment and disposal to ground (or evaporated) Early 1980s to present 2000s

4 Oldest System 1980s Modern Practice

5  Less stringent regulation than wastewater ◦ Non-numeric standards ◦ BMPs  First Phase II NPDES permit: 2007 ◦ Public Education and Involvement ◦ Illicit Discharge Detection and Elimination ◦ Construction stormwater controls ◦ Post-construction stormwater management ◦ Municipal Pollution Prevention and Good Housekeeping

6  Second Phase II NPDES permit cycle: 2014 ◦ Enhances existing requirements ◦ Adds regional effectiveness studies ◦ Requires jurisdictions to “allow” low impact development ◦ Require developments to retain on-site runoff from the 10-year storm event

7  EPA: Green Infrastructure  Stormwater Management ◦ Retention and infiltration ◦ Storm gardens, green roofs, permeable pavement  Land Use Management ◦ Preservation of natural features ◦ Minimize construction disturbance area ◦ Minimize impervious area No curbs Reduced Street Width (11% less impervious area) Reinforced Grassy Shoulders Bioretention Cells Reduced runoff by 99%

8  Spokane Urban Runoff Greenways Ecosystem  Storm garden bio-infiltration cells  Treated stormwater flows to Cannon Hill Park Pond

9  Constructed 2010  Bio-infiltration cells (storm gardens)  Permeable sidewalk  Urbanized area  Infiltration

10  LID demonstration site and regional stormwater facility at 42 nd and Freya

11  Ecology grant awarded to Spokane County ◦ Due date: June, 2013  Eastern WA Phase II Jurisdictions  Washington Stormwater Center: ◦ Public Comment ◦ Interactive educational website

12  PCB Consent Decree - Supplemental Environmental Project I: LID ◦ Formation of Internal LID Subcommittee and Technical Advisory Committee ◦ Educational materials  Utility Bill Insert  Brochure  Website: ◦ Formation of Stakeholders Group Draft ordinance with monetary or other incentives to City Council by August 2013

13  Reference the Eastern WA LID Guidance Manual ◦ Streamline permitting process ◦ Guidance on what LID technologies are available and suitable for Eastern Washington  Assess existing City code ◦ Refer to ordinances applicable to LID

14  What are PCBs?  Man-made compounds  “Banned” in 1977 but sources remain  Doesn’t break down readily  209 Congeners  Why are we concerned?  Spokane River out of compliance with standards  Ecology sampling found PCBs in City of Spokane stormwater and CSO  Carcinogen that accumulates in food chain  What are we doing?  City of Spokane: PCB Consent Decree and permit-required wastewater monitoring  Spokane River Regional Toxics Task Force

15 Union Stormwater Basin CSO 34 Drywells

16  Sample and analyze for PCB Aroclors and Congeners

17  Review Aroclor analysis results ◦ Residential cleanup std. 1.0 mg/kg  Remove all sediments from catch basins  Dump on separate pad, mix with sawdust  Haul to lined cell at landfill

18 432 CBs [Union and HI CSO 34] 280,000 pounds 26 grams PCBs removed CBs [CSO 34 up- gradient] 268,000 pounds 3.7 grams PCBs removed CBs [Most Union, 4 HI CSO 34] 39,600 pounds 2.7 grams PCBs removed 2012

19  Automatic flow-weighted composite sampling

20  Goal: 6 samples per site  Wet season  Event mean concentration  Compare congener patterns  Compare to previous samples (Ecology) Level Flow Rate Sample Aliquots

21  Integrated Plan ◦ Basin priority  Total PCB load greater than Union basin?  Sampling spring 2013

22  Samples collected wet season ◦ DO TMDL-related parameters  BOD, phosphorus, ammonia ◦ Metals ◦ Suspended solids ◦ Fecal Coliform ◦ Total Coliform ◦ PCBs  Flow rate and volume

23  Integrated Plan ◦ Flow Volume ◦ Pollutant concentration ◦ Comparison to CSOs  NPDES Permit and DO TMDL ◦ Estimate pollutant concentrations in typical City stormwater


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