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
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. www.villanova.edu/vusp 2
A test! Why do most storms happen at nights and over weekends? Workweek = 40 Hours Hours in a week 40/168 = 24%
Philadelphia Water Department 1902-2000 Percent less then 100.00 90.00 80.00 70.00 60.00 50.00 40.00 30.00 20.00 10.00 0.00 Percent Storm Percent Capture 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6 6.5 7 7.5 Rainfall
Rainfall (inches) 6 5 4 3 2 1 0 Chadds Ford 1999-2001 Depth (in.) 1 12 23 34 45 56 67 78 89 100 111 122 133 144 155 166 177 188 199 210 221 23 24 25 26 27 28 event Per Year 28 events > 0.5 in 12 events > 1.0 in 6 events > 1.5 in (1948 2001) www.villanova.edu/vusp 5
When did this storm start & stop?
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
Villanova s BMP SCM Research and Demonstration Park Green Roof 8
Villanova s BMP SCM Research and Demonstration Park Porous Pavements Infiltration Trenches 9
Stormwater Wetlands www.villanova.edu/vusp 10
Philadelphia Water Department Green City Clean Waters
User fees: a tale of two properties 1700 Market Street 6723 Essington Ave Year 1700 Market Monthly fee 6723 Essington Monthly fee 09 10 1364.70 364.98 10 11 1195.35 782.10 11 12 994.68 1196.05 12 13 765.66 1599.81 13 14 536.64 2003.57
Will probably need several SCMS to significantly reduce their fees 6723 Essington Avenue
Approach Goals Site specific testing Design Maintenance/monitoring
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
Green Roof
Yearly Performance 1400 ET and Overflow (mm) 1200 1000 800 600 400 200 Overflow ET 0 2009 2010 2011 Average regional yearly precipitation approximately 1145 mm Data for Apr Nov
Rain Garden Can have underdrain Bioretention Or not! bioinfiltration 18
Drainage Area 1.3 Ac 46% Impervious 10:1 DCIA to SCM 450 in/yr
Constructed in 2001 ~4 ft excavation, filled with a 1:1 sand/soil mixture Planted with vegetation typically found along the eastern seaboard
Hydrologic Performance www.villanova.edu/vusp 21
Output from SlopeFinder program 0.5 BioInfiltration Traffic Island 30 0.4 20 10 0 Temp. [C] Recession Rate [in/hr] 0.3 0.2 0.1 seven point moving average best fit periodic function 0 Y = 0.24-0.058*Sin(X(days)/55) 2003 2004 2005 2006 BTI (4.25 years of data) EMERSON www.villanova.edu/vusp 22
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)
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
Infiltration trench 100 Infiltration Trench 30 Emerson 20 10 Temp. [C] (log scale) Incremental Slope [in/hr] 10 1 0 0.1 5 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
PAPC No difference in pavement types Pavements performing well Overflows about once per year (rain event over 2 in) No change in infiltration rate
The future is now In series to prolong life Better accounting for evapotranspiration
Many thanks to: PA DEP US EPA Prince Georges County RMC Foundation William Penn Foundation VUSP Villanova University