modeling to support green infrastructure planning best management practice-decision support system...
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Modeling to Support Green Infrastructure Planning
Best Management Practice-Decision Support System (BMP-DSS) Application
Andrew Parker
Director, Water Resources Group
www.modelingwater.com
► Component of Sustainable Modeling Toolbox (SuMiT)
► Developed for detailed site-scale planning
► Evaluate effectiveness of green technologies in a watershed
► Considers hydrology and water quality
► Models Best Management Practices (BMPs)
► Can be applied at watershed scale
► Includes post-processing capabilities
► Available to the public (www.modelingwater.com)
BMP-DSS Model
BMP Simulation► Two Major BMP Categories
Storage/detention Open channel
► Physical Process Representation Evapotranspiration Infiltration Orifice and underdrain outflow Weir-controlled overflow spillway Bottom slope and roughness influence General loss or decay of pollutant
► Depending on design and type of BMP, any combination of processes may occur during simulation
Analysis
► Long-term
► Weekly
► Multi-storm
► GIS Integration
In the works…
► BMP Optimization
Water Conservation/Recycling Techniques
Integrate in-home and on-site water management to better manage storm water runoff at the site scale
Case Study
• Bowie, Maryland, U.S.A.• Developing area• Lot size is approx. 1.25
acres• 26 % imperviousness
(rooftop & paved area)• Pervious area (bare
ground & gravel filled area)
Study Area
Approach
► Generate surface hydrology input using watershed model (LSPC – part of SuMiT)
► Run existing condition (A)
► Run pre-development (O)
► Run scenarios
B RT --> RG, PA --> RGC RT --> Toilet & RG, PA --> RGD RT --> RG --> LF, PA --> RGE RT --> RG --> LF, PA --> NG
Scenarios DescriptionRT – RooftopRG – Rain GardenPA – PavementLF – Leach FieldRG – Natural Ground
Potable water from well Rooftop and paved area are part of runoff Septic system disposes of household waste
Existing Condition (A)
Values in 1,000 cubic feet
Potable water from well Rooftop and paved area are part of runoff Septic system disposes of household waste
Existing Condition (A)
ALTERNATIVES CONSIDEREDALTERNATIVES CONSIDERED
-Rooftop runoff diverted to cistern, overflow to rain garden
-Recycled water is used for flushing-Pavement runoff to rain garden
Scenario C
Estimated BenefitsEstimated Benefits
33% Runoff Reduction27% Reduction in use of potable water
Values in 1,000 cubic feet
Scenario C
Annual Water Balance
-
50,000
100,000
150,000
200,000
250,000
Input Scenario 0(Pre-dev)
Scenario A(existing)
Scenario B Scenario C Scenario D Scenario E
Vo
lum
e (f
t3/y
r)
Outflow
ET
Infiltration
Precip
Water Balance
Storm Event Analysis
Storm Response
BMP-DSS Summary
► Publicly available tool to support green planning
► Designed for urban areas, but applicable elsewhere
► Can be incorporated into larger scale watershed planning
► Provides quantitative data for engineering design
► Basis of systems developed throughout the U.S.A. for stormwater management and nonpoint source pollution control
