1 / 43

Pimples to Dimples

A regulatory perspective on our efforts to control runoff from new construction in CA. Greg Gearheart, PE Storm Water Program / SWRCB. Pimples to Dimples. I wish to acknowledge the hard work of my colleagues at the State Water Board in helping gather information used in this presentation:

caraf
Télécharger la présentation

Pimples to Dimples

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. A regulatory perspective on our efforts to control runoff from new construction in CA. Greg Gearheart, PE Storm Water Program / SWRCB Pimples to Dimples

  2. I wish to acknowledge the hard work of my colleagues at the State Water Board in helping gather information used in this presentation: • Eric Berntsen, PH, CFM, CPESC, CPSWQ • Bill Hereth • Laurel Warddrip

  3. Dimples

  4. Regulating Symptoms vs. Causes

  5. The Tail (of the Dragon) • The mission of the Water Boards is to preserve and enhance the quality of CA’s water resources, and ensure their proper allocation and efficient use for the benefit of present and future generations.

  6. Millions of Californians • 1980 – 23.7 million • 2005 – 37 million • 2030 – 48 million (projected) • where?

  7. New Construction Numbers • In FY 2008-2009: ~17,000 enrollees in our construction permit • ~3,000 new enrollees • Today: • ~15,000 enrollees/facilities • ~250 new enrollees per month • ~50 acres per facility = ~750,000 acres • Despite economic conditions, enrolment fairly consistent

  8. 2000's – Sacramento Area 1950's – Sacramento Area

  9. Driven by maintenance interests...

  10. Water Boards nuts and bolts • Our regulatory actions (e.g., CWA401 Certs, WDRs, NPDES Permits, enforcement, etc.) require discharges to be protective of our water quality standards (WQS): • Water quality standard = beneficial uses + objectives • Water Boards may “choose to prevent any degradation”

  11. CWA - Water Quality Standards • Water Quality Standards are made up of: • Beneficial Uses (designated to specific waterbodies), plus • water quality criteria; and • an antidegradation policy. • Beneficial Uses (BUs) are: • often not directly related to key water resource uses valued by communities (it might take a suite of them to protect wetlands and streams, for example)

  12. REC-1 – Water Contact Recreation REC-2 – Non-Water Contact Recreation SHELL – Shellfish Harvesting SPAWN – Fish Spawning WARM – Warm Freshwater Habitat WILD – Wildlife Habitat WQE – Water Quality Enhancement Beneficial Uses Used to Protect California Wetlands & Streams • AGR – Agricultural Supply • FLD – Flood Peak Attenuation/Flood Water Storage • FRSH – Freshwater Replenishment • GWR – Groundwater Recharge • MAR – Marine Habitat • MUN – Municipal and Domestic Supply • RARE – Preservation of Rare and Endangered Species

  13. Functional Framework:Regulatory Tools • Landscape (laparoscopic?) and watershed tools: • Storm Water NPDES Permits • CEQA ? • Waterbody tools: • CWA 401 Certifications / Wetland program • Project tools: • Construction permit, CEQA, local ordinances, building code?

  14. Clean Water Act Permits • CWA Section 402 – Point Sources • The National Pollutant Discharge Elimination System (NPDES) – applies to all point sources of pollutants • Storm water outfalls are considered “point sources” and these regulations apply to: • Industrial Sources (including Construction Activities) • BAT/BCT standard applies • Municipal Sources (large and small communities) • MEP standard applies

  15. MS4s and MEP • Municipal Separate Storm Sewer System (MS4) • Local governments, Caltrans, and some “non-traditionals” in Phase II • Maximum Extent Practicable (MEP) • MS4s must reduce pollutants in their effluent to the MEP • A hybrid standard – part performance-based and level of effort ($)

  16. MS4 Permits are supposed to ensure WQS are met via MEP standard applied at “ends of pipes.” MS4 Water Quality Standards (WQS) apply to receiving waters. LID

  17. MS4 requires project to use LID to reduce pollutants to MEP to protect WQS WQS MEP MS4 LID Receiving Water Limitations Effluent Limitations Permittee Desired Practice (applied to project)

  18. Enforcing Post-construction Standards via MS4 Permits • City Y has an MS4 Permit that requires all projects adding over 10,000 square feet of impervious area, etc., to do LID to meet the 5% EIA standard • Project X in City Y fails to comply (or worse, fakes compliance) • Project X is built w/o compliance → City Y is in violation • State/EPA must enforce against City Y

  19. NPDES Permit Drivers towards LID • 1990's – MS4s had to have post-construction elements in their plans • ~2000 – MS4s had to have Standard Urban Stormwater Management Plans (SUSMPs) • capture/treat 85 %ile, 24-hr runoff event • often resulted in regional basins • difficult to enforce

  20. Modern MS4 Tools • SUSMPs (the plan, not necessarily the standard) • Hydromodification Management Plans (HMPs) • Low Impact Development • Additional post-construction elements (e.g., water quality BMPs)

  21. Common Triggers for Projects Required to do LID, etc. • >10,000 square feet of impervious • “Priority projects” - varies statewide • Older permits may trigger at 20,000 square feet • other thresholds

  22. Common Project Outcomes • Older permits • Large vaults, structural devices • Detention basins • Capture/treat approach • Newer permits • LID • Flow duration control • Hydromod/instream intervention in some cases

  23. Common Performance Criteria • Criteria (varies) • “Post equals pre-development” runoff volume • Ranges of flows to control • (Effective) Impervious area threshold(s) • Method of analysis/calculation (varies) • Continuous simulation • Rational (modified) method • Not specified

  24. Specific LID Requirements • Construction General Permit requires “post equals pre” and uses LID-esque runoff credits (trees, cisterns, etc.) • LID Manuals (some developed, some in progress) • Vague “LID preferential” language in some cases • Some MS4 permits contain no LID language

  25. Subdivision Example

  26. Subdivision Example

  27. Effective Impervious Area (EIA) • Concerns over using EIA as a surrogate for hydrologic performance • Treats the symptom (surface), not the cause (hydrology) of WQS impacts • Could be gamed (the “grassy moat” scenario) • Should use Runoff Volume, Time of Concentration, and other appropriate hydrologic metrics instead

  28. The importance of soil • Healthy soils are critical to watershed health and function • Engineers tend to focus on the plumbing more than the soils and biotic features • Infiltration and recharge do not always work – LID is flexible, why aren't we?

  29. Native Soil From King County

  30. Disturbed Soil From King County

  31. From Soil Food Web, Inc

  32. Risks of over-engineered LID • Engineered boxes often require engineered soils • Devices buried in corners of commercial lots • Site runoff performance may meet goals, but overall watershed goals and sustainability of project is questionable

  33. Challenges Ahead for LID • Regulating LID • Retrofits, hydrologic criteria, performance measurement, over-engineering, enforcement, linking to WQS and outcomes • Legislating LID • Diverse interests, oversimplification of CA hydrology, promises of global savior • Mother Nature

  34. Sustainability Tests • Resource – protection to enhancement and reuse (“runoff is a resource”) • Technical – complex, technological standard-based to simple, natural, performance-based solutions • Institutional – centralized, subsidized approaches to decentralized, self-supporting approaches • Community – healthy individual, societal cost driven equations to healthy community, community opportunity equations

  35. My Recommendations • Water Board/USEPA should develop numeric criteria and objectives that address hydromod impacts using LID, instream, and other techniques – in support of beneficial uses and WQS • Wherever feasible, directly regulate those responsible for constructing projects (and maintaining BMPs), discharging storm water • Open source model → performance-based standards with flexibility to adapt/learn • Promote sustainable approaches to water management wherever feasible (soils, irrigation, gray water, everything)

  36. Greg Gearheart | 916-341-5892 | ggearheart@waterboards.ca.gov

More Related