Effective Best Management Practices in Urban Areas

1. Effective Best Management Practices in Urban Areas Chad Christian City of Tuscaloosa, AL Robert Pitt University of Alabama Tuscaloosa, AL

2. “Energy Independence and Security Act of 2007” signed into Law on Dec. 19, 2007 • Title IV (“Energy Savings in Building and Industry”), Subtitle C (“High Performance Federal Buildings”) Sec. 438 (“Storm Water Runoff Requirements For Federal Development Projects”): • “The sponsor of any development or redevelopment project involving a Federal facility with a footprint that exceeds 5,000 square feet shall use site planning, design, construction, andmaintenance strategies for the property to maintain or restore,to the maximum extent technically feasible, the predevelopmenthydrology of the property with regard to the temperature, rate,volume, and duration of flow.” • This new provision requires much more attention to controlling runoff volume, in addition to other hydrologic features.

3. Conservation Design Approach for New Development • Better site planning to maximize resources of site • Emphasize water conservation and water reuse on site • Encourage infiltration of runoff at site but prevent groundwater contamination • Treat water at critical source areas and encourage pollution prevention (no zinc coatings and copper, for example) • Treat runoff that cannot be infiltrated at site

4. A lot of stormwater flow and quality data has been collected during the past several decades It is important to compare these observations with model assumptions and to use this data for calibration and verification

5. Many types of runoff monitoring have been used to calibrate and verify WinSLAMM, from small source areas to outfalls.

7. WinSLAMM Source Area, Land Use, Drainage System, and Outfall Controls

8. Probability distribution of rains (by count) and runoff (by depth). Central Alabama Rain Condition: <0.5”: 65% of rains (10% of runoff) 0.5 to 3”: 30% of rains (75% of runoff) We therefore need to focus on these rains! 3 to 8”: 4% of rains (13% of runoff) >8”: <0.1% of rains (2% of runoff) 3” 8” 0.5”

9. Conducted a preliminary evaluation of the downtown Tuscaloosa area that contains the redevelopment sites. Soils are mostly hydrologic group B which is classified as silt, loam, and silt-loam, having typical infiltration rates of about 0.5 in/hr, although most of the soils are highly disturbed and will need to be restored.

10. Separated area into six subareas of several blocks each and conducted detailed field surveys and modeling for each land use. This is one subarea.

11. Directly connected roofs Landscaping Driveways Streets Directly connected paved parking areas Major sources of suspended solids in the drainage area for different sized rains. Fairly consistent pattern because of the large amount of impervious surfaces in the drainage basin and the highly efficient drainage system.

12. Calculated Benefits of Various Roof Runoff Controls (compared to typical directly connected residential pitched roofs)

13. Green(ish) Roof for Evapotranspiration of Rain Falling on Building (Portland, OR)

14. Recent results showing green roof runoff benefits compared to conventional roofing (data from Shirley Clark, Penn State – Harrisburg) Greater than 65% volume reductions due to ET

15. Rain water tanks to capture roof runoff for reuse (Heathcote, Australia)

16. Recent Bioretention Retrofit Projects in Commercial and Residential Areas in Madison, WI

17. Runoff volume benefits of many rain gardens capturing roof runoff in neighborhood 97% Runoff Volume Reduction Land and Water, Sept/Oct. 2004

18. Stormwater filters adjacent to buildings treating roof runoff (Melbourne, Australia and Portland, Oregon)

19. Neenah Foundry Employee Parking Lot Biofilter, Neenah, WI

20. Typical Biofiltration Facility WDNR, 2004 infiltration standard 1004

21. Example Biofilter Performance and Design using WinSLAMM 0.75 inch rain with complex inflow hydrograph from 1 acre of pavement. 2.2% of paved area is biofilter surface, with natural loam soil (0.5 in/hr infilt. rate) and 2 ft. of modified fill soil for water treatment and to protect groundwater. No Underdrain Conventional Underdrain Restricted Underdrain

23. Small grass filters/biofilters for commercial area runoff (Melbourne, Australia)

24. Tree planter biofilters along sidewalk (Melbourne, Australia)

25. 116 ft TSS: 10 mg/L 75 ft TSS: 20 mg/L 25 ft TSS: 30 mg/L 6 ft TSS: 35 mg/L 3 ft 2 ft TSS: 63 mg/L TSS: 84 mg/L Date: 10/11/2004 Head (0ft) Example grass filter monitoring results, Tuscaloosa, AL TSS: 102 mg/L

26. Large parking areas, convenience stores, and vehicle maintenance facilities are usually considered critical source areas and require runoff treatment before infiltration or surface discharge.

27. Continuous Simulation can be used to Determine Needed Treatment Flow Rates: - 90% of the annual flow for SE US conditions is about 170 gpm/acre pavement (max about 450). - treatment of 90% of annual runoff volume would require treatment rate of about 100 gpm/acre of pavement. More than three times the treatment flow rate needed for NW US. Flow distribution for typical Atlanta rain year

28. Chamber Filtering Systems Hydrodynamic Separator Commonly used underground treatment units for critical source areas

29. Multi-Chambered Treatment Train (MCTT) for stormwater control at large critical source areas Milwaukee, WI, Ruby Garage Maintenance Yard MCTT

30. EPA-funded SBIR2 Field Monitoring Equipment for UpFlow Filter, Tuscaloosa, AL

31. Test site drainage area, Tuscaloosa, AL (anodized aluminum roof, concrete and asphalt parking areas; total of 0.9 acres)

32. Treatment Flow Rate Changes during 10 Month Monitoring Period of Prototype UpFloTM Filter

33. Upflow filter insert for catchbasins Able to remove particulates and targeted pollutants at small critical source areas. Also traps coarse material and floatables in sump and away from flow path. HydroInternational, Ltd. Currently being installed for full-scale testing in Tuscaloosa, AL)

34. Installation of full-sized UpFlow Filter at Tuscaloosa for long-term monitoring

35. Filtration Performance

36. We are using CFD (Fluent 6.2 and Flow 3D) to determine scour from stormwater controls; results being used to expand WinSLAMM analyses after verification with full-scale physical model • This is an example of the effects of the way that water enters a sump on the depth of the water jet and resulting scour CFD Modeling to Calculate Scour/Design Variations

37. Calculated annualized total life cycle costs and runoff reductions for different stormwater controls (110 acre downtown Tuscaloosa, AL, example)

38. Calculated annualized total life cycle costs and TSS reductions for different stormwater controls (110 acre downtown Tuscaloosa, AL, example)

39. Appropriate Combinations of Controls • No single control is adequate for all problems • Only infiltration reduces water flows, along with soluble and particulate pollutants. Only applicable in conditions having minimal groundwater contamination potential. • Wet detention ponds reduce particulate pollutants and may help control dry weather flows. They do not consistently reduce concentrations of soluble pollutants, nor do they generally solve regional drainage and flooding problems. • A combination of bioretention and sedimentation practices is usually needed, at both critical source areas and at critical outfalls.

40. Combinations of Controls Needed to Meet Many Stormwater Management Objectives • Smallest storms should be captured on-site for reuse, or infiltrated • Design controls to treat runoff that cannot be infiltrated on site • Provide controls to reduce energy of large events that would otherwise affect habitat • Provide conventional flooding and drainage controls Pitt, et al. (2000)