Presented October 4, 2011 at a brownbag discussion on the upcoming Phase 1 and Phase 2 Municipal Stormwater Permit changes to incorporate LID.

1. LOW IMPACT DEVELOPMENT STORMWATER APPROACH Overcoming Barriers to Implementation

2. Brickyard Park and Ride May 2009 June 2010 Project is a 200 stall expansion of an existing King County Metro Park and Ride lot located in unincorporated King County.

3. Stormwater Management Approach Pervious asphalt pavement with distributed detention storage in shallow arch-pipe system. Biofiltration swale for WQ treatment. n

4. Topography and Groundwater

5. Brickyard: Drainage Section Arch pipe detention system section

6. 60% Design Cost Comparison Cost Savings = $88,000 or 3.8% of Construction Cost Cost Assumptions: Subtract 8 CBs and 630 LF of 12-inch pipe Decrease detention storage by about ½ or 16,000 cubic feet Decrease earthwork cut and haul (due to less detention storage) Add washed crushed base course material

7. Construction

8. Paving Day – August 28, 2009

9. Completed Paving

10. When Something Goes Wrong

11. Repairs

12. Common Barriers to Use of LID Unfamiliarity Design team, permitting agency, owner, contractor, etc. Do you have public support for your ROW project? Site limitations (soils, slopes, high groundwater, etc.) Cost (perceived and/or real) Local code limitations Risk/Liability (both to owner and design team)

13. Risk Mitigation Take Advantage of Continuing Professional Education LID Certification Classes are offered locally Webinars – Contract Language/Risk Management Attend Professional Conferences – ASCE International Conference on LID Start Small to Build Confidence and Experience Seek Highly Collaborative Project Teams LID methods require an understanding of natural systems that include the surrounding ecology, soil, and plant communities. This requires close collaboration of people across disciplines (architect, civil, geotech, landscape architect, environmental scientist, etc.) Partner with suppliers and builders early in design to increase success

14. Amie Broadsword, PE, LEED AP amieb@paceengrs.com 425-827-2014 A Special Thank You to Today’s Sponsors!