Nonpoint Source Storm Water Management Plan

Transcription

1 Nonpoint Source Storm Water Management Plan Christine Pomeroy Dept. of Civil & Environnmental Eng. University of Utah Carl Adams Watershed Protection Utah Division of Water Quality

2 Definitions Nonpoint Source Pollution diffuse source of water pollution into surface and ground water. Stormwater runoff from developed areas. Best Management Practice a structural or operational water pollution control practice Pollutant contaminant that impairs the beneficial use of water

3 Pollutants of Concern Sediment siltation, channel aggradation Nutrients algae growth Organic matter depletes dissolved oxygen Trash impairs recreational and wildlife use Toxics human health, fish kills Metals long term health effects Pathogens human health

4 Storm Water Pollution Concerns Stormwater pollutant loads increase with population and associated development. A leading source of water quality impairment in urban and developing areas. Global concern for human health and environment.

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7 Goal of Plan Accelerate the adoption of effective pollutant control practices into local authorities (cities, counties) own stormwater management plans Demonstrate the effectiveness of practices Share this information with relevant audiences

8 Activity Review surrounding state plans 2. Review 319 Requirements/prepare plan outline 3. Prepare 1 st draft plan/bmp appendix 4. Review plan with coalitions/ stakeholders 5. Prepare 2 nd draft plan/bmp appendix 6. Present draft to WQ Board and NPS Task Force 7. Prepare 3 rd draft plan/bmp appendix 8. Agency and general public review and comment 9. Prepare final draft addressing public & agency comments 10. Attorney General review & certification 11. Prepare final plan for EPA submission 12. Transmittal of final plan to EPA

9 Plan Features Best Management Practice Analysis Tool How to measure success Appendix of Best Management Practices Eligible sources of funding

10 Clean Water Act and Stormwater Rules has evolved over time Early on stormwater dischargers were generally exempted from permitting requirements Court cases in the late 70 s through mid 80 s Permitting component established in Water Quality Act of 1987 Individual and General Permits Municipal, Industrial, and Construction

11 Municipal Separate Storm Sewer System MS4 Owned by a state, city, town, village, or other public entity that discharges to waters of the U.S. Designed or used to collect or convey stormwater (including storm drains, pipes, ditches, etc.) Not a combined sewer; and Not part of a Publicly Owned Treatment Works (sewage treatment plant)

12 MS4 Permit Requirements Develop and implement a Stormwater Management Program Reduce pollutants to the maximum extent practicable through implementation of Best Management Practices (BMPs) BMPs have to be identified in the plan along with measurement goals

13 Stormwater Management Plan Measurable Goals Specific Actions (BMPs) Updated annually - iterative process

14 Storm Water Management Plan Six Minimum Control Measures Public Education and Outreach Public Involvement/Participation Illicit Discharge Detection and Elimination Construction Site Storm Water Runoff Control Pollution Prevention and Good Housekeeping for Municipal Operations Long-Term Storm Water Management

15 Long-Term Storm Water Management Objectives: Mimic pre-development hydrology Infiltrate, transpire or beneficially use storm water Encourage a LID approach where practicable

16 Hydrologic Impacts of Land Use Change Increased peak flow of runoff Increased volume of runoff Increased duration of discharge Increased pollutant loadings Increased temperature of runoff

17 National Research Council, 2008 Until recently increases in runoff volume and peak discharge rates have been regulated through state and local flood control programs. Although these programs have merit knowledge accumulated during the past 20 years has led stormwater experts to the conclusion that conventional approaches to control runoff are not fully adequate to protect the nation s water resources.

18 Limitations of Traditional Detention 100-, 25-, 10-, 2-year flows Not fully adequate to protect downstream hydrology Poor peak control for small, frequently-occurring storms Negligible volume reduction Increased duration of peak flow Minimal water quality benefit

19 Post-Construction Runoff Control Needs to Involves More Than a 10-yr/24-hr Storm

20 Energy Independence and Security Act of Section 438 The sponsor of any development or redevelopment project involving a Federal facility shall use site planning, design, construction, and maintenance strategies for the property to maintain or restore, to the maximum extent technically feasible, the predevelopment hydrology of the property with regard to the temperature, rate, volume, and duration of flow.

21 Retain the 95% Event 100% of the volume from storms <= the 95th percentile event should not be discharged to surface waters. The 95th percentile rainfall event is the event whose precipitation total is greater than or equal to 95 percent of all storm events over a given period of record. Accomplish by the use of practices that infiltrate, evapotranspire and/or harvest and use rainwater.

22 Site Specific Hydrologic Analysis Post-development = pre-development. Control runoff rate, volume, duration and temperature. Predevelopment hydrology replicated through site design and other appropriate practices. Use of infiltration, evapotranspiration, and/or rainwater harvesting and use. Defensible and consistent hydrological assessment tools.

23 Best Management Practices Capture, Retention, Detention (CRD) Filters, Flow Control, Separators (FFCS) Impervious Surface Reduction (ISD) Bioretention Surface Sand Filter Street Design Constructed Wetlands Underground Filter Cul-de-Sac Design Retention Systems Oil/Grit Separator Driveway Design Detention Systems Check Dams Parking Lot Design Dry Swales Dikes, Berms, Swales Permeable Pavement Rainwater Harvesting Proprietary Flow Control Green Rooftops Infiltration Basins Devices Infiltration Trenches Management (MGMT) Vegetative Measures (VM) Pavement Management Filter Strips BMP Maintenance Aquatic Buffers Pet Waste Management

24 BMP Fact Sheets Potential applications. Brief description. Site considerations. Design guidelines. Maintenance recommendations.

25 Functions by collecting, infiltrating, and treating applied water through biological and physical processes CRD: Bioretention

26 CRD: Constructed Wetlands Stormwater wetlands are designed specifically for the purpose of treating urban runoff Typically less biodiversity

27 Traditional control release can be extended for water quality treatment of smaller storms. CRD: Detention Systems

28 CRD: Dry Swales

29 CRD: Rainwater Harvesting Capture, Storage, Reuse

30 CRD: Infiltration Basins Areas designed to retain and infiltrate stormwater

31 FFCS: Sand Filters

32 ISD: Permeable Pavements Porous Asphalt Pervious Concrete Permeable Interlocking Concrete Pavers Grid Paver Systems Other Ceramic Tiles, Flexipave

33 Captures stormwater (quantity and quality control); reduces heat island effect, reduces building energy use for cooling. ISD: Green Roofs

34 Management Pavement (Street Sweeping) Pet Waste BMP Maintenance

35 Funding Opportunities EPA Website concerning external funding opportunities: Clean Water State Revolving Fund (CWSRF): Targeted Watershed Grants Program: Environmental Quality Incentives Program: North American Wetlands Conservation Act Grants Program: Five Star Restoration Program:

36 Funding Opportunities (ctd) National Integrated Water Quality Program (NIWQP): htp:// Watershed Rehabilitation Program: The National Urban & Community Forestry Advisory Council (NUCFAC) Urban & Community Forestry Challenge Cost- Share Grants: EPA Smart Growth Grants: NPS Grants

37 Summary Stormwater is a significant water quality concern in urban and developing areas. New and innovative practices are required to address stormwater issues. Appropriate sizing of BMPs is critical. The Nonpoint Source Stormwater Management Plan will help accelerate the adoption and use of effective BMPs.

38 Questions? Carl Adams Christine Pomeroy