Ohio; Rain Garden Design and Monitoring - Ohio State University

8/3/2019 Ohio; Rain Garden Design and Monitoring - Ohio State University

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Rain Garden Design & Monitoring

Jay Martin, Ph.D., and Derek Schlea

Ohio State University


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What the results will be used for

Increase guidance

Lack of information on networks

Engineering design standards Retrofits

Promote the technology


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Table 1. Summary of individual and laboratory studies of benefits of rain gardens or bioretention areas related to storm water flow

and quality (Davis et al. 2009). Previous results have reported reductions of metals (Davis et al. 2003, Hunt et al. 2008)

Site location /description

Parameter Load Reduction (%) Citation

Stormwater Flow Results

Burnsville, MN flow 90 Barr Engineering 2006

Haddam, CN flow 98 Dietz and Clausen 2006

Greensboro, NC flow ~50 Hunt et al. 2006

College Park, MD flow 49-58 Davis 2008

Charlotte, NC flow 96 Hunt et al. 2008

Water Quality Results

College Park, MD TSS 59 Davis 2007

College Park, MD TSS 54 Davis 2007

Durham, NH TSS 97 UNHSC 2006

Villanova, PA TSS 99 USEPA 2006

Haddam, CN Total N 32 Dietz and Clausen 2006

Greensboro, NC Total N 40 Hunt et al. 2006

Chapel Hill, NC Total N 40 Hunt et al. 2006

Louisburg, NC Total N 65 Sharkey 2006

Durham, NH Total N 97 UNHSC 2006

Pilot boxes Total N 30-99 Davis et al. 2006

College Park, MD Total P 79 Davis 2007

College Park, MD Total P 77 Davis 2007

Haddam, CN Total P -111 Dietz and Clausen 2006Greensboro, NC Total P -240 Hunt et al. 2006

Chapel Hill, NC Total P 65 Hunt et al. 2006

Louisburg, NC Total P 69 Sharkey 2006

Villanova, PA Total P 28 USEPA 2006

Pilot boxes Total P 50-99 Davis et al. 2006

Laboratory columns Total P 63-85 Hsieh et al. 2007

College Park, MD Zn 54 Davis 2007

College Park, MD Zn 69 Davis 2007

Villanova, PA Zn 74 USEPA 2006

Durham, NH Zn 99 UNHSC 2006


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Goals and Objectives

Hydrology

Quantify volume and peak flow reductions

Compare to control neighborhood

Water Quality

Quantify nutrient reductions

Modeling Application to additional watersheds


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Garden

Locations


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Street-Side Garden Design

Retrofit

Space limited

Utilities

Tile drainage


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Street-Side Garden Design

Sizing

Terracing


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Monitoring What to Measure

Hydrology

Rainfall

Volume, peak flow, time to peak

Rise in water table in gardens

Water Quality

Nutrients

Solids


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Monitoring - Equipment

Tipping bucket rain gauge

Storm sewer flow meters


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Water quality grab samples

Storm events

Various locations

Time intervals


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Water level logger / pressure transducers

Piezometers


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Preliminary Results Hydrology

Water level hydrograph


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Preliminary Results Hydrology


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Controlled Experiments

What?

Observe garden response to known watervolume and rate inputs

Water balance equation


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Controlled Experiments

Eliminate the unknowns of water balance

Inflow volume

Bi-pass flow

Tile drain flow


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Controlled Experiment (12-10-10)


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Controlled Experiment (12-10-10)


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Controlled Experiment Results

-2.5

-2.0

-1.5

-1.0

-0.5

0.0

0:00 4:00 8:00 12:00 16:00 20:00 0:00 4:00 8:00 12:00 16:00 20:00

Time

WaterDepth,

feet

bgs

0

5

10

15

20

25

30

Inflow,gpm

K

L

Inflow


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Controlled Experiment Results

Waterbalance

Tiledrainage


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Next Steps

Quantify maximum volume retention

= depth * width * length * porosity

Quantify seepage losses Better estimations of water balance

Compare with outfall flow data

Mass balance for nutrients Load reductions


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Ongoing Learning

Modify methods to increase accuracy

Develop a model

Use data we have

Gather data we need


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Current Status

Observations show the gardens areworking

Working to quantify these observations

Continuing controlled experiments

More data

Predict infiltration rates for different inflows


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Thank you!

Documents

Ohio; Rain Garden Design and Monitoring - Ohio State University