Monitoring Flow and Quality for Stormwater Control Measures

Transcription

1 Monitoring Flow and Quality for Stormwater Control Measures Robert Traver, Ph.D., PE, D.WRE. Andrea L. Welker, PhD, PE Bridget Wadzuk, PhD, John Komlos, PhD

2 The mission of the Villanova Urban Stormwater Partnership is to advance sustainable stormwater management and to foster the development of public and private Partnerships through research on innovative SWM Best Management Practices, Directed Studies, Technology Transfer and Education. 2

3 A test! Why do most storms happen at nights and over weekends? Workweek = 40 Hours Hours in a week 40/168 = 24%

4 Philadelphia Water Department Percent less then Percent Storm Percent Capture Rainfall

5 Rainfall (inches) Chadds Ford Depth (in.) event Per Year 28 events > 0.5 in 12 events > 1.0 in 6 events > 1.5 in ( ) 5

6 When did this storm start & stop?

7 Type of SCM Control Runoff Volume Stormwater Control Measure Goals Reduce Pollutants Control Peak Runoff Rates Promote Evapotranspiration Establish Wetland Structure and Function Infiltration: Infiltration Trench/Bed, Pervious Pavement Yes Yes Yes No No Bioinfiltration: Rain Garden, Swales Yes Yes Yes Yes No Evapotranspiration: Green Roof Naturalized: Constructed Wetland, Wet Pond Yes Yes Yes Yes No Yes Yes Yes Yes Yes

8 Villanova s BMP SCM Research and Demonstration Park Green Roof 8

9 Villanova s BMP SCM Research and Demonstration Park Porous Pavements Infiltration Trenches 9

10 Stormwater Wetlands 10

11 Philadelphia Water Department Green City Clean Waters

12 User fees: a tale of two properties 1700 Market Street 6723 Essington Ave Year 1700 Market Monthly fee 6723 Essington Monthly fee

13 Will probably need several SCMS to significantly reduce their fees 6723 Essington Avenue

14 Approach Goals Site specific testing Design Maintenance/monitoring

15 Green roof Captures ~0.5 to 1 in of rain Promotes evapotranspiration Increases insulation Cooling effect Potential problems plant health during droughts, export of nutrients Pervious pavement Captures ~1 to 2 in of rain Promotes infiltration Potential problems clogging Rain gardens Captures ~0.5 to 1.5 in of rain Promotes evapotranspiration and infiltration Adds beauty Cooling effect Potential problems invasive species, maintenance

16 Green Roof

17 Yearly Performance 1400 ET and Overflow (mm) Overflow ET Average regional yearly precipitation approximately 1145 mm Data for Apr Nov

18 Rain Garden Can have underdrain Bioretention Or not! bioinfiltration 18

19 Drainage Area 1.3 Ac 46% Impervious 10:1 DCIA to SCM 450 in/yr

20 Constructed in 2001 ~4 ft excavation, filled with a 1:1 sand/soil mixture Planted with vegetation typically found along the eastern seaboard

21 Hydrologic Performance 21

22 Output from SlopeFinder program 0.5 BioInfiltration Traffic Island Temp. [C] Recession Rate [in/hr] seven point moving average best fit periodic function 0 Y = *Sin(X(days)/55) BTI (4.25 years of data) EMERSON 22

23 Water Balance Flow Pollutants Evapotranspiration Bowl Surface Storage Infiltration Bowl Overflow Discharge Media Root Zone Lower Media Storage Percolation Underdrain Discharge Native Soils Groundwater Baseflow Davis, et al. (2012)

24 Infiltration SCMs Permeable pavements Infiltration trench 0.47 Ac 100% Impervious 130:1 DCIA to SCM 5,900 in/yr 0.18 Ac 100% Impervious ~1:1 DCIA to SCM

25 Infiltration trench 100 Infiltration Trench 30 Emerson Temp. [C] (log scale) Incremental Slope [in/hr] to 4 ft 4 to 3 ft 3 to 2 ft 2 to 1 ft 1 to 0.1 ft 0.01 Jul-04 Jan-05 Jul-05 Jan-06 Jul-06 Jan-07

26 PAPC No difference in pavement types Pavements performing well Overflows about once per year (rain event over 2 in) No change in infiltration rate

27 The future is now In series to prolong life Better accounting for evapotranspiration

28 Many thanks to: PA DEP US EPA Prince Georges County RMC Foundation William Penn Foundation VUSP Villanova University