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

Thank You!

For more information, visit:

www.modelingwater.com