Low Impact Development (LID) & Storm Water Regulations

1. Low Impact Development (LID) & Storm Water Regulations Low Impact Development for City Engineers and City Planners Seminar June 10, 2015 Division of Water Quality Jeanne Riley

2. Presentation Overview • Background: what is LID why it is an important tool for managing storm water • How LID fits into the storm water regulations • Current and future Utah MS4 permit requirements for incorporating LID

3. Reduce Runoff: Slow it down, Spread it out, Soak it in

4. What is LID? • Approach which mimics a site’s predevelopment conditions • Techniques that: • Infiltrate • Filter • Store • Evaporate • Detain runoff close to its source

8. TypicalTraditional Storm Water System

9. Philosophy Change • Previous Collect and dispose of storm water quickly using engineered systems • Here to Forward Mitigate impacts, reverse damage caused by development, apply LID, emulate functions of natural systems to reintegrate rainfall into the water cycle rather than disposing of it as a waste product

10. LID and Green Infrastructure Green infrastructure uses natural hydrologic features such as vegetation, soils, and natural processes to manage water and provide environmental and community benefits. At the scale of a city or county, green infrastructure refers to the patchwork of natural areas that provides habitat, flood protection, cleaner air, and cleaner water. At the scale of a neighborhood or site, green infrastructure refers to storm water management systems that mimic nature by soaking up and storing water.

11. City Scale Green Infrastructure

12. Site Scale Green Infrastructure

13. Bioretention

14. Green Roofs

15. Rainwater Harvesting

16. Pervious Concrete

17. LID and Storm Water Permitting

18. National Storm Water Rulemaking • EPA began developing new rules in 2010 • Current approach unlikely to adequately control storm water’s contribution to water body impairment • Retention based national performance standard for new development and redevelopment activities based on percentile storm water capture

19. Anticipated Requirements for MS4s • Development disturbing 1 acre or more (or CPDs); must design, install, implement, and maintain SW control measures that infiltrate, evapo-transpirate, and/or harvest storm water. • Post-construction hydrology shall not exceed pre-development hydrology in accordance with a numeric performance standard.

20. Individual States Must Develop their own Numeric Standard Storm Water Rule Deferred

21. Numeric Post Construction Standards in MS4 Permits

22. MS4 PermitsSix Minimum Control Measures • Public Education and Outreach on Storm Water Impacts • Public Involvement/Participation • Illicit Discharge Detection and Elimination (IDDE) • Construction Site Storm Water Runoff Control • Long-Term Storm Water Management in New Development and Redevelopment (Post-Construction) • Pollution Prevention and Good Housekeeping for Municipal Operations

23. Utah Small MS4 General UPDES Permit No. UTR090000 • “The objective of this control measure is for the hydrology associated with new development to mirror the pre-development hydrology of the previously undeveloped site or to improve the hydrology of a redeveloped site and reduce the discharge of storm water. “ (4.2.5) • “The program shall include a process to evaluate and encourage a Low Impact Development (LID) approach which encourages the implementation of structural BMPs, where practicable, that infiltrate, evapotranspire or harvest and use storm water from the site to protect water quality. Structural controls may include green infrastructure practices such as rainwater harvesting, rain gardens, permeable pavement, and vegetated swales.” (4.2.5.3.2)

24. Utah’s MS4s & LID Implementation Expectation for MS4 Programs: • Ordinance or other enforceable mechanism requiring evaluation of LID • LID Standards/Specifications for developers • Master Plan or City Directive • Evaluate use of LID for all new/re development • > 1 acre (or CPD) • Define hydrologic methods to evaluate pre and post construction runoff volumes and flow rates

25. Curb breaks and at SLC maintenance facility

27. Utah’s MS4s & LID Implementation • Obstacles to LID • Maintenance • Cost uncertainty • Ordinance/city code/zoning • Outdated design standards • Site constraints (soil /groundwater) • Underground Injection Wells (UIC) • Rainwater harvesting laws

28. Conceptual Design LID & Project Development Discuss maintenance agreement Provide LID design resources Preliminary Design LID Included? If not, provide rationale. Discuss Ordinance/ City code requirements Review LID design Final Design Opportunities for LID during construction? Review pre/post development Hydrology Calculations Monitor maintenance SWPPP/ Pre-Construction Offer development incentives Provide storm water utility fee reduction/ waiver Finalize maintenance agreement Construction Provide oversight & LID verification Maintenance Phase

29. Resources Low Impact Development Center http://www.lowimpactdevelopment.org/ LID Urban Design Tools Website http://www.lid-stormwater.net/ US EPA Low Impact Development (LID) Website LID “Barrier Busters" Fact Sheet Series and LID Design Manual http://water.epa.gov/polwaste/green/

30. Questions? Jeanne Riley jriley@utah.gov 801-536-4369 Rhonda Thiele rthiele@utah.gov 801-536-4396