1. Effective Stormwater Management Through the Use of Low-Impact Development (LID) Techniques Justin Gregory, PE Jones Edmunds & Associates October 3, 2012

2. OVERVIEW 10-3-12Net Zero through Emerging Technologies2 Low Impact Development Current stormwater problems New Facilities RetrofitSwalesRegulations

3. Current Stormwater Situation 10-3-12Net Zero through Emerging Technologies3 ImpairmentsTMDLs and BMAPs Energy Independence and Security Act

4. Current Stormwater Situation 10-3-12Net Zero through Emerging Technologies4 Traditional solutions not working well enough. How do we meet our stormwater management goals?

5. Low Impact Development 10-3-12Net Zero through Emerging Technologies5 LID / Green Stormwater Infrastructure DistributedTreatment train Replicate natural hydrologic response

6. NASA Propellants North Admin & Maintenance Facility 10-3-12Net Zero through Emerging Technologies6 LEED Platinum Designed to reach net-zero energy Rainwater harvesting key aspect of design

7. NASA Propellants North Admin & Maintenance Facility 10-3-12Net Zero through Emerging Technologies7 7,500-gallon rainwater harvesting. Supplies: Toilets. Irrigation. Treated water for drinking and hand washing. Other LID components

8. Sunset Boulevard Bioretention 10-3-12Net Zero through Emerging Technologies8 Community facing large nutrient load reduction goals Erosion problemLID Retrofit Opportunity

9. Existing Conditions 10-3-12Net Zero through Emerging Technologies9 Direct discharge to Indian River Lagoon Erosion problems at discharge to Lagoon Limited space within the ROW High infiltration rates

10. Solution 10-3-12Net Zero through Emerging Technologies10 Offline bioretention Median Swale/Inverted Median

11. Solution 10-3-12Net Zero through Emerging Technologies11 Curb cuts Overflow - Extreme Events. Inverted median advantages 30% more volume than swales. Normal Flow. Overflow during extreme events

12. Performance 10-3-12Net Zero through Emerging Technologies12 8” Rainfall 7-9 Oct 2011. Visual Monitoring. No observed runoff. Recovered overnight. Costs TN < 30% conventional treatment. No land purchase needed.

13. Sarasota County Swale Study 10-3-12Net Zero through Emerging Technologies13 Enhance County-wide pollutant loading model Measure effects of conveyance swales Account for possible load reductions

14. Sarasota County Swale Study 10-3-12Net Zero through Emerging Technologies14 Promote distributed infiltration Disconnect impervious area Common in Sarasota County Versus

15. Phillippi Creek Basin 10-3-12Net Zero through Emerging Technologies15 2 curb & gutter sites3 swale sites Besides drainage type all else was equal 7 months/40 samples

16. Phillippi Creek Basin 10-3-12Net Zero through Emerging Technologies16

17. TSS 10-3-12Net Zero through Emerging Technologies17 78% lower Statistically significant Literature 61-86%

18. Nitrogen 10-3-12Net Zero through Emerging Technologies18 TN - 68% lower.TKN – 72% lower.Nox – 22% lower. Highest removal particulate nitrogen.

19. Phosphorus 10-3-12Net Zero through Emerging Technologies19 TP - 25% lower. Ortho-Phosphorus – 17% lower. Not statistically different.

20. Runoff 10-3-12Net Zero through Emerging Technologies20 Rainfall vs. Percent Runoff 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% 00.511.522.5 Rainfall, in. Percent Runoff Runoff Coefficient 58% lower 3x as much rain without runoff 5x lower annual runoff volume

21. Observed Load Differences 10-3-12Net Zero through Emerging Technologies21 TN – 93%TP – 81%TSS – 95%BOD – 93%

22. LID Constraints 10-3-12Net Zero through Emerging Technologies22 Technical.Inertia.Regulatory.

23. LID Manuals 10-3-12Net Zero through Emerging Technologies23 Local Design Standards.Account for local hydrology.Provide reasonable assurance. Meet WMD Permitting Requirements. Promote LID.

24. Local Hydrology 10-3-12Net Zero through Emerging Technologies24 Varies across the state. Significantly effects LID performance. How do we account for this? Sarasota Jacksonville

25. Local Design Curves 10-3-12Net Zero through Emerging Technologies25 Consider local climate. Consider local hydrology. Simplify permitting. Allow for BMAP credits.

26. Key Components 10-3-12Net Zero through Emerging Technologies26 Alter practices for local conditions. Work with end user of the manual. Performance based design curves. Average annual effectiveness.

27. Conclusion 10-3-12Net Zero through Emerging Technologies27 LID provides additional tools to meet our stormwater requirements. Replicate natural runoff response.

28. Conclusion 10-3-12Net Zero through Emerging Technologies28 Distributed stormwater treatment. Design should consider all removal mechanisms Infiltration Settling Filtration Sorption Biogeochemical processes