Active Hydromodification Control Judd Goodman, P.E. Marcus Quigley, P.E.
Active Hydromodification Control Judd Goodman, P.E. Marcus Quigley, P.E.
LID and Hydromodification
“The primary goal of Low Impact Development methods is to mimic the predevelopment site hydrology by using site design techniques that store, infiltrate, evaporate, and detain runoff.” -Prince George's County, Maryland (1999)
Hydromodification = Hydrograph Modification
What is Hydromodification?
Flow Duration Control
Active Hydromodification Control
Outline
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What is Hydromodification?
Hydromodification = Changes in runoff characteristics and in-stream processes caused by altered land use.
What is Hydromodification?
Restoration vs. Hydromodification Management
Fix an existing geomorphic
impact
Prevent a future geomorphic
impact 5
What is Hydromodification?
Pre-Development
flow flow
Post-Development
Pre-Urban
Post-Urban
Time
Dis
char
ge
Qc
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What is Hydromodification?
Pre-Development Post-Development
flow flow
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Flow Duration Control
Qcritical
Pre-Development Post-Development
Q10
Flow Duration Control
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= X% Q2
Route post-development runoff through BMPs to mimic pre-development hydrology.
Flow Duration Control
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Regional Detention
Onsite Bioretention Underground Detention/Retention
CONTECH
StormTrap
Flow Duration Control
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Hydromodification LID BMPs look the same as for surface water quality, except they are larger!
Flow Duration Control
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Planting Media
Gravel Sump
Surface Ponding
Riser
Slotted Underdrain
Cleanout
Low Flow Orifice
Distributed LID = simple outlet
high flows dictate sizing for this LID BMP with simple
outlet structure
for rest of the flow range, the pre-
development curve is above the post-
development curve
Flow Duration Control
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Active Hydromodification Control
Active Hydromodification Control
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Active Hydromodification Control
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OptiRTC Function
SWMM
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Opti is a cloud-native platform that uses sensor data, forecast information, and modeling to actively control stormwater infrastructure.
Passive: 1.32 inches Active: 0.60 inches
Active Hydromodification Control
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Retrofit Existing flood basins and BMPs can
provide hydromodification control New Development BMP size decreases, reduces cost Adaptive Management Data available in real-time Adjust flow releases without physical
retrofit Flow monitoring and calibration
Benefits of Active Control with OptiRTC
Active Hydromodification Control
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Field Installation Steps
Steps 1 & 2 Create flow duration curves for the Pre- and Post-Development (w/out BMP) runoff conditions based on continuous hydrologic simulation
Step 4 Create Revised Flow Rating Curve: Qout = f (Qin, Qcrit)
Steps 5 – 9 Create Control Curves: % Open = f (Qout, Depth)
Step 10 Create Control Logic Code to lookup Control Curve based on Qin and BMP Depth Example: RULE 1.00 IF NODE Storage DEPTH > 0.75 AND NODE Storage DEPTH <= 1.00 AND NODE Storage INFLOW >= 0 THEN ORIFICE 1 SETTING = CURVE 1.00
Step 11 Create BMP Stage-Storage Curve based on assumed geometric configuration
Step 12 Run continuous hydrologic simulation for post-development conditions (with BMP)
Step 13 Does the Post-Development (with BMP) flow duration curve match the Pre- Development with minimum BMP footprint and volume?
Step 13 (continued) Revise the BMP geometric configuration
Step 14 Install BMP with geometric configuration, outlet configuration, and control logic modeled
Step 15 Monitor Qin, Qout, & BMP Depth
Step 16 Is the monitored Qin consistent with modeled Qin results ?
Step 16 (continued) Recalibrate continuous hydrologic simulation modeling parameters based on monitored data
Step 17 Update flow duration curves for Pre- and Post-Development (w/out BMP) runoff conditions based on continuous hydrologic simulation
Step 17 (continued) Update Revised Flow Rating Curve: Qout = f (Qin, Qcrit)
Step 17 (continued) Update Control Curves: % Open = f (Qout, Depth)
Step 18 Reprogram Control Curves that Control Logic Code looks up
Yes No
Yes
No
Step 3 Create Initial Flow Rating Curve: Qpre vs. Qpost
Step 17 (continued) Update Initial Flow Rating Curve: Qpre vs. Qpost
Active Hydromodification Control Methodology Flowchart
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