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City of Spokane Stormwater. Spokane River Forum Conference March 26, 2013. Municipal Separate Storm Sewer System (MS4). About 1/3 of City 130 outfalls. Spokane’s Stormwater History. 1890. 1900. 1920. 1940. 1950. 1960. 1970. 1980. 1990. 2000s. Spokane’s Stormwater History. 1980s.

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city of spokane stormwater

City of Spokane Stormwater

Spokane River Forum Conference

March 26, 2013

municipal separate storm sewer system ms4
Municipal Separate Storm Sewer System (MS4)
  • About 1/3 of City
  • 130 outfalls
spokane s stormwater history
Spokane’s Stormwater History

1890

1900

1920

1940

1950

1960

1970

1980

1990

2000s

spokane s stormwater history1
Spokane’s Stormwater History

1980s

Oldest System

Modern Practice

regulatory framework
Regulatory Framework
  • 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
regulatory framework1
Regulatory Framework
  • 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
low impact development lid
Low Impact Development (LID)
  • 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

Seattle SEA Streets

Reduced runoff by 99%

Bioretention Cells

Reinforced Grassy Shoulders

Reduced Street Width (11% less impervious area)

No curbs

lincoln surge
Lincoln SURGE
  • Spokane Urban Runoff Greenways Ecosystem
  • Storm garden bio-infiltration cells
  • Treated stormwater flows to Cannon Hill Park Pond
broadway surge
Broadway SURGE
  • Constructed 2010
  • Bio-infiltration cells (storm gardens)
  • Permeable sidewalk
  • Urbanized area
  • Infiltration
hazel s creek
Hazel’s Creek
  • LID demonstration site and regional stormwater facility at 42nd and Freya
eastern wa lid guidance manual
Eastern WA LID Guidance Manual
  • Ecology grant awarded to Spokane County
    • Due date: June, 2013
  • Eastern WA Phase II Jurisdictions
  • Washington Stormwater Center: www.wastormwatercenter.org
    • Public Comment
    • Interactive educational website
city of spokane and lid
City of Spokane and LID
  • PCB Consent Decree - Supplemental Environmental Project I: LID
    • Formation of Internal LID Subcommittee and Technical Advisory Committee
    • Educational materials
      • Utility Bill Insert
      • Brochure
      • Website: www.spokanewastewater.org/LID.aspx
    • Formation of Stakeholders Group
  • Draft ordinance with monetary or other incentives to City Council by August 2013
draft lid incentives ordinance
Draft LID Incentives Ordinance
  • 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
polychlorinated biphenyls pcbs
Polychlorinated Biphenyls (PCBs)
  • 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
pcb investigations
PCB Investigations

Drywells

Union Stormwater Basin

CSO 34

catch basin sediments
Catch Basin Sediments
  • Sample and analyze for PCB Aroclors and Congeners
pcb remedial maintenance
PCB Remedial Maintenance
  • 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
stormwater characterization union basin
Stormwater Characterization: Union Basin
  • Automatic flow-weighted composite sampling
stormwater characterization union basin1
Stormwater Characterization: Union Basin
  • Goal: 6 samples per site
  • Wet season 2012-2013
  • Event mean concentration
  • Compare congener patterns
  • Compare to previous samples (Ecology)

Level

Flow Rate

Sample Aliquots

stormwater characterization washington basin
Stormwater Characterization : Washington Basin
  • Integrated Plan
    • Basin priority
  • Total PCB load greater than Union basin?
  • Sampling spring 2013
stormwater monitoring cochran basin
Stormwater Monitoring: Cochran Basin
  • Samples collected wet season 2012-2013
    • DO TMDL-related parameters
      • BOD, phosphorus, ammonia
    • Metals
    • Suspended solids
    • Fecal Coliform
    • Total Coliform
    • PCBs
  • Flow rate and volume
stormwater monitoring cochran basin1
Stormwater Monitoring: Cochran Basin
  • Integrated Plan
    • Flow Volume
    • Pollutant concentration
    • Comparison to CSOs
  • NPDES Permit and DO TMDL
    • Estimate pollutant concentrations in typical City stormwater