Urban Runoff - Storm Water 101

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  • Q’s: Very familiar with stormwater program ? How many pretreatment operators ? How many municipalities – phase I ? II ?
  • NPDES permit is a “license to discharge”
  • Point source – includes stormwater from industrial , construction & storm sewers - does not include agriculture return flows
  • Urban Runoff - Storm Water 101

    1. 1. Urban Runoff Greg Gearheart State Water Resources Control Board
    2. 2. Urban Runoff Problems • Pollution – Beach closures – Water quality impairment – Fish kills – Plastic debris • Physical alteration of the watershed / water bodies – Stream incision / erosion / deposition – Habitat destruction
    3. 3. Hydrologic Changes Runoff Time Pre-Development Urbanization tends to increase storm water runoff:  peak flows  volume  frequency Post-Develop. From Haltiner (2006)
    4. 4. Regulatory Solution • Stormwater Program – A Clean Water Act-based program – A permitting solution – “Forces” stormwater peg into the existing hole designed to protect surface waters – Has evolved over the years to include new tools and connect to TMDLs
    5. 5. Overview of the Clean Water Act • Federal Water Pollution Control Act of 1972, amended 1977 – NPDES programs – Permits are a privilege, not a right – Effluent limits must be both technology and water quality based • 1987 – added Section 402(p) to CWA covering stormwater
    6. 6. Overview of the Clean Water Act • All “point sources” • “Discharging a pollutant” • Into a “Water of the U.S” >>>>Must obtain a NPDES (National Pollutant Discharge Elimination System) Permit
    7. 7. What is a Point Source ? • Point Source – Discharge though a discrete conveyance into waters of the US • Industrial facilities • Sewage treatment plants • Stormwater from industrial sites and storm sewers – Non-point source • Runoff that is not a point source
    8. 8. What is a Water of the U.S ? • All waters currently used, used in the past, or susceptible to use for interstate commerce including all waters which are subject to the ebb and flow of the tide
    9. 9. US Waters – Examples • Rivers, lakes and streams • Tributaries • Territorial seas • Wetlands • Ephemeral washes
    10. 10. Stormwater Program Overview • Municipal Program – urban runoff • Industrial Program – industrial sector specific runoff • Program Overlap – Many industrial sites discharge INTO Municipal Separate Storm Sewer Systems (MS4s)
    11. 11. Municipal Stormwater Permits • Municipal Separate Storm Sewer Systems (MS4s) – Phase I • Municipalities > 100,000 population – Phase II • Small municipalities and others – 9th circuit court decision 1992
    12. 12. MS4 – Phase 1 • 26 Regional Water Board Phase I MS4 Permits • Covering over 1000 entities in CA • 1 Statewide - Caltrans Permit
    13. 13. Municipal Permits • Municipal permits (under Phase I) areMunicipal permits (under Phase I) are issued by Regional Boards for:issued by Regional Boards for: • Municipalities > 100,000Municipalities > 100,000 • Contiguous municipalities sharing aContiguous municipalities sharing a large MS4large MS4 • Small municipalities covered underSmall municipalities covered under Phase II regulationsPhase II regulations
    14. 14. MS4 Phase II – 6 Minimum Program Elements • Education an Outreach • Public Participation/Involvement • Illicit Discharge Detection and Elimination • Construction Site Runoff Control • Post Construction Runoff Control • Pollution Prevention/Good Housekeeping
    15. 15. MS4 – Phase I Issues • June 19, 2006 - State Water Board released Blue Ribbon Panel Report • Municipal Discharges - Panel Recommended • (Action Levels and improve accountability) • Impaired water bodies and TMDLs are being implemented through MS4 permits • Over 1000 cities, counties, and other governmental agencies regulated – significant
    16. 16. MS4 – Phase II • Current permit requires MS4s to enroll and for Rbs to approve SWMP • About 150 MS4s currently “covered” • New Phase II permit being drafted
    17. 17. Industrial Stormwater Permits • Industrial General Permit (SB Order 97-03-DWQ) – Sector/SIC code specific • Construction General Permit (SB Order No. 99-08-DWQ) – Construction and development industry – All projects that disturb 1 acre or more of land must obtain coverage
    18. 18. DRAFT Program report cards developed by Rafael Maestu in the Office of Research, Planning and Performance
    19. 19. Industrial Facilities DRAFT Program report cards developed by Rafael Maestu in the Office of Research, Planning and Performance
    20. 20. DRAFT Program report cards developed by Rafael Maestu in the Office of Research, Planning and Performance
    21. 21. Industrial Facilities DRAFT Program report cards developed by Rafael Maestu in the Office of Research, Planning and Performance
    22. 22. Industrial Permit • Over 500 Standard Industrial Codes (SIC) regulating specific industries • Landfills, auto dismantlers, refineries, plastic products, etc. • Plastic
    23. 23. DRAFT Program report cards developed by Rafael Maestu in the Office of Research, Planning and Performance
    24. 24. Construction DRAFT Program report cards developed by Rafael Maestu in the Office of Research, Planning and Performance
    25. 25. DRAFT Program report cards developed by Rafael Maestu in the Office of Research, Planning and Performance
    26. 26. Construction DRAFT Program report cards developed by Rafael Maestu in the Office of Research, Planning and Performance
    27. 27. Plastic Debris Program • ~400 facilities regulated under the industrial general permit (IGP) • ~3000 facilities statewide that handle preproduction plastic pellets in some manner • Part of global problem – fate and transport in the environment of plastic is impressive
    28. 28. The Construction Stormwater Program
    29. 29. Construction Activity Threats • Two-fold – construction projects have the potential to cause impacts to our beneficial uses of water both during and after the project. • During – potential for sediment erosion discharges. • After – potential for pollutant export and hydromodification impacts as a result of how the new landscape functions.
    30. 30. + + =Construction WQ threats
    31. 31. Who needs coverage 1) All sites that disturb more than one acre 2) All sites that are less than one acre but part of a “larger plan of development” 3) All sites that are thought to be a threat to water quality, as deemed by the appropriate RWQCB
    32. 32. Permit Reissuance Goals 1) Adopt a risk-based permit approach- “not all sites are created equal” 2) Improve “performance” measurement of program 3) Establish standards to avoid, minimize and mitigate post-construction impacts associated with all new and re- development projects triggering the construction activity permit
    33. 33. Program “Performance” Elements • Certification and training expectations • Effluent monitoring = feedback for site amd program • Receiving water monitoring = feedback for “water quality outcome” goals/objectives • Performance-based post-construction runoff standards (pre = post)
    34. 34. Risk Approach • Three risk categories • Aimed at sediment transport and receiving water risk of construction activities “normal distribution” assumption (most projects should not be high risk) • Incentives/requirements linked to risk.
    35. 35. Direct Erosion / Sediment Control Requirements • Old model used SWPPP as main vehicle • New approach to use Rain Event Action Plan (REAP) as primary tool (SWPPP becomes more a master document/library) • Requirements based on risk • Prevention and planning incentives
    36. 36. Post-Construction Impacts
    37. 37. Post-Construction Standards • Design to mimic pre-development water balance • Preserve existing time of concentration • Protect channels
    38. 38. After Lane (1955) as cited in Rosgen (1996)
    39. 39. Channel Changes Associated with Urbanization
    40. 40. The future • Low Impact Development (LID) and Green Infrastructure (GI) represent “natural systems” approach to building better urban landscapes. • Both aim to protect and/or restore “natural hydrology” and ecological processes • LID – site and neighborhood scale • GI – community and watershed scale
    41. 41. Ways to mimic pre-development water balance and Tc  Soil quality improvement (porosity)  Native and drought tolerant vegetation  Trees  Permeable pavement  Riparian buffers  A general reduction of connected, impervious surfaces in runoff pathways  Bioretention  Disconnected downspouts/rain chains/rain barrels
    42. 42. Ideal Soil Structure for Plant Growth Mineral 45% Organic Matter 5% Water 25% Air 25%
    43. 43. Rain chains and mulch combo Sacramento
    44. 44. Greg Gearheart 916.341.5892 ggearheart@waterboards.ca.gov

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