Opti-Tool: A BMP Optimization Tool for Stormwater Management in EPA Region 1

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1 Opti-Tool: A BMP Optimization Tool for Stormwater Management in EPA Region 1 Mark Voorhees, EPA Region 1 Khalid Alvi, Tetra Tech April 20, 2016

2 Project Background Massachusetts (MA) MS4 General Permit Phosphorus reduction requirement to meet the Waste Load Allocations for the impaired watershed Phosphorus Control Plan (PCP) To measure compliance with its phosphorus reduction requirement under the permit 3 implementation phases Reporting on beginning 6 year after the permit effective date Complete in 20 years Opti-Tool A tool to facilitate storm water engineers to developing Nutrient Management Plans such as PCP. 2

3 Project Background cont. Proven benefits of optimization techniques in stormwater management Charles River watershed study Practical needs by stormwater practitioners BMP simulation BMP optimization Independent of ArcGIS Simple to use 3

4 Opti-Tool A spreadsheet-based BMP optimization tool Planning Level Analysis (EPA Region 1 BMP Performance Curves) Implementation Level Analysis (EPA SUSTAIN BMP Simulation and Optimization Engine) Customized for EPA Region 1 4

5 Interface for data input Interface for data input Internal data validation Internal data validation No All inputs validated? Yes EXCEL SOLVER No All inputs validated? Yes SUSTAIN BMP Simulation & Optimization BMP Performance Curves Post-processing component Interpreted optimization results Interpreted optimization results Microsoft Excel Environment 5

6 Opti-Tool: Region Specific Data Precipitation conditions Long-term hourly data at Logan airport ( ) Land representation Stormwater monitoring data to calibrate the buildup & washoff processes on impervious cover Long-term landuse specific annual average load export rates BMP representation University of New Hampshire Stormwater Center (UNHSC) BMP monitoring data to calibrate flow and pollutant loss mechanism in BMPs Representative BMP cost information with scaling function 6

7 Opti-Tool: Buildup & Washoff Calibration Data used National Stormwater Quality Database (NSQD) Massachusetts and New Hampshire sites 100% impervious drainage areas Storm events smaller than 1 inch Pollutants (TN and TP) Buildup & Washoff parameterization Develop computer codes using GA algorithms to identify the parameter pattern that best fit the observed data Perform sensitivity analysis to identify the robust set of parameters 7

8 Buildup/Washoff: Calibration Plots for TN 8

9 Opti-Tool: Land Use Timeseries Development Develop pollutant runoff timeseries Calibrated SWMM model with selected set of buildup & washoff parameters Regional representative landuse-based pollutant annual average load export rates (kg/ha/yr) Buildup parameters adjusted to match the simulated long-term annual average load rate (kg/ha/yr) Hourly timeseries (1992 to 2014) Compare the simulated EMC distribution against the observed EMC distribution for impervious land use types 9

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11 Opti-Tool: BMP Calibration Data used BMP design specifications (from the UNHSC) BMP monitoring data (from the UNHSC) BMP parameterization Develop SUSTAIN models Represent BMP pollutant loss mechanism (1 st order decay and underdrain removal rate) BMP hydrologic and water quality performances were calibrated against the observed data 11

12 Hydrology Calibration: Bioretention Observed Observed inflow inflow Generated Generated inflow to bio-retention inflow to bio-retention area area Observed Observed outflow outflow Calibrated Calibrated BMPDSS BMPDSS outflow outflow Flow (gpm) Flow (gpm) :40 20:00 21:00 20:20 21:20 20:40 21:40 21:00 22:00 21:20 22:20 21:40 22:40 22:00 23:00 22:20 23:20 22:40 23:40 23:00 0:00 23:20 0:20 23:40 0:40 0:00 1:00 0:20 1:20 0:40 1:40 1:00 2:00 1:20 2:20 1:40 2:40 2:00 3:00 2:20 2:40 3: :00 20:20 Time Time 12

13 Opti-Tool: BMP Performance Curve Data used Calibrated SUSTAIN model Calibrated hourly land use timeseries (1992 to 2014) BMP simulation Run model scenarios for various BMP storage capacity and estimated the pollutant load reductions Develop BMP performance curve (load reduction vs storage capacity) Long-term cumulative nutrient load and runoff volume reduction performances for several categories of structural SW controls 13

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15 Opti-Tool: BMP Types Bioretention Bioretention with internal storage reservoir Dry Pond Grass Swale Gravel Wetland Infiltration Basin Infiltration Chambers Infiltration Trench Porous Pavement Sand Filter Wet Pond 15

16 Opti-Tool: BMP Cost Function Combination of the Charles River Watershed Association and UNHSC costs estimates Modified capital cost assessment (includes a fixed percentage for Design and Contingency Costs) Maintenance hours (from the UNHSC) 16

17 Select Pollutant Type -> TP Total BMP Cost ($) $3,739,640 Enter Target Load Reduction (%) -> 20.00% Total Pollutant Load Reduction (%) 20.00% Select an option -> BMP Storage Capacity 3,069,121 Enter Land Use Area -> Click Here Total Impervious Area (ac) Enter Drainage Area -> Click Here Total Treated Impervious Area (ac) BMP Type 1. Management Objective 2. Optimization Target 5. Optimal Solution Design Storage Capacity (ft 3 ) Total BMP Storage Capacity (gal) 3. Watershed Information 4. BMP Information BMP Cost ($) Treated Impervious Area (ac) O&M (hr) Load Reduction (lbs) Biofiltration with ISR - $ Bioretention 72,567 $ 1,061, Dry Pond - $ Grass Swale - $ Gravel Wetland 79,639 $ 661, Infiltration Basin 108,901 $ 643, Infiltration Chambers - $ Infiltration Trench 76,561 $ 904, Porous Pavement - $ Sand Filter - $ Wet Pond 72,615 $ 467, * Note:Only fill in the yellow highlighted cells. Planning Level Analysis The purpose of this tool is to provide decision-makers a comprehensive overview of stormwater management opportunities in a given watershed. The tool will characterize the watershed characteristics and opportunities for applying a variety of BMP technologies to various source areas based on land use, soils, and impervious cover. There are two approaches of the planning-level analysis tool: 1: BMP Storage Capacity to evaluate the changes in hydrologic and water quality benefits as the BMP/LID sizes are increased in fixed increments; and 2: BMP Drainage Area to determine how much impervious area would require treatment if specified BMP design capacities are selected for each HRU type to be treated. Run Single Scenario Run Optimize Scenario Return to Home Page 17

18 Opti-Tool: Implementation Level Analysis Subwatershed Conduit/stream channel BMPs Optimization setup File operation Input parameters with default values SUSTAIN input file + Post-processing SUSTAIN Optimizer 18

19 Opti-Tool: Bartlett Brook Drains to Lake Champlain, VT Impaired waterway on the 2006 Vermont 303(d) Sub-watershed land use distribution similar to Bartlett Brook watershed Opti-Tool demonstration focus Develop cost-effectiveness curve for TP annual average load reduction 19

20 Opti-Tool: Model Inputs Subwatershed delineation HRU representation Landuse, soil, slope combination Runoff timeseries (flow, pollutant load) BMP type and design specification BMP cost function BMP treatment area delineation BMP/Subwatershed routing network 20

21 Opti-Tool: Model Setup 21

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23 Cost (Million $) Opti-Tool: Model Results Target Reduction Solution Total Solution Reduction (%) Cost (Million $) (%) 30.0% 3.24E % All Solutions Selected Best Solution BMP ID BMP Type BMP Area (ft^2) BMP Storage Depth Treated 12 Impervious Area Annual Maintenance (ft) (ac) (hours) Cost ($) BMP1 DRYPOND ,600 BMP2 DRYPOND ,159,808 BMP3 DRYPOND ,199 BMP4 DRYPOND ,701,632 BMP5 DRYPOND , % 10% 20% 30% 40% 50% 60% 70% % Reduction (Annual Average Load) 23

24 Summary Opti-Tool for a wide range of users Municipal officials State and EPA staff (stormwater and nonpoint source programs) Consultants Software requirement Microsoft Excel Customized for EPA Region 1 Regionally calibrated land use based pollutant runoff timeseries Regionally calibrated BMP performance curves Regionally representative BMP cost function Results are consistent with loading rates and BMP performance documented in the upcoming EPA Region 1 MS4 permits The tool can be readily adapted to represent site specific loading and climate conditions throughout the region 24