Are Bmps Environmentally Friendly

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Are Bmps Environmentally Friendly?

• Guest Lecture
• Larry A. Roesner, Ph.D., P.E.
• Professor, Urban Water Infrastructure Systems
• Colorado State University
• April 27, 2000

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Effect of Urbanization on the Discharge Frequency
Curve
Peak Flow
Post-Development Curve
Pre-Development Curve
0.3
1
10
0.1
100
2
Return Period, yrs
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Stormflow Impacts

• 100 year peak flow increases 2 X
• 15 year peak flow increases 3 X
• 2 year peak flow increases 57 X
• 2-yr peak flow occurs 3 X per year (res dev)
• 6 X per year
  (comm.)

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Flood Control Facility
Photos by Bill Wenk
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Typical Detention Facility
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Effect of Urbanization on the Discharge Frequency
Curve
Peak Flow
Post-Development Curve
0.3
1
10
0.1
100
2
Return Period, yrs
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The Urban Stormwater Problem
Flow
Quality
Regulated by Local Drainage Agencies
Regulated by Regional and Federal
Environmental Agencies
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The Joint ASCE/WEF MOP

• Introduction to Urban Runoff
• Developing Municipal Stormwater Management
  Programs
• Monitoring Modeling and Performance Auditing
• Source Controls
• Selection and Design of Passive Treatment
  Controls

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Dead Possum BMP
Any Roads worker happening upon road kill shall
not ignore same, but rather pick it up gingerly
by the tail (lest it still have some bite left)
and dispose of it properly by heaving same to the
side of the road. DO NOT PLACE IN STORM SEWER,
SINCE IT DRAINS TO RECEIVING WATER
NOT MY JOB
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The STORM Model(Storage Treatment Overflow
Runoff Model)
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Typical Runoff Capture Curves
The Design Storm
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Runoff Capture EfficiencyEdinburgh
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Return Interval of Water Quality Storms
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Range of Post-Development Storms Controlled by
BMPs
Peak Flow
Post-Development Curve
3 - 10 storms/yr exceed the BMP treatmentvolume
0.3
1
10
0.1
100
2
Storms Controlled by BMPs
Return Period, yrs
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Post-Development Flow Frequency Curve with BMPs
and Flood Control
3 - 10 storms/yr still have uncontrolled releases
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What is Required

• A paradigm shift in our attitude toward urban
  water management is needed
• We must view urban stormwater as an asset, not a
  liability
• Fishable-swimmable urban streams are not required
  nor always desired
• Design of stormwater facilities must address the
  entire flow frequency curve

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Infiltration Trenches in Scotland
Photos by Kirsteen McDonald
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Retrofitted Infiltration TrenchEmsher River,
Germany
Photos by Dreiseitl
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Extended Detention
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Extended Detention (cont)
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Extended Detention
Outlets (cont)
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Extended Detention (cont)
Outlets
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Extended Detention (cont)
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Retention w/ Added Detention
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Where Do We Start
INFILTRATION IS WIDELY USED IN JAPAN
Courtesy Shoichi Fujita
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Lot/Site Drainage
Depressed Grassed Area
Modular Pavement
Grassed Parking Area Reinforced with Geotextile
Fabric
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Lot/Site Drainage
A Church Parking Lot
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Denver is Experimenting
Photos by Bill Wenk
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Mitigating Channel Erosion
Photos by Bill Wenk
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Storm Water Management is not Just Engineering
or Biology
Courtesy North Central Texas Council of
Governments
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Conclusions

• A paradigm shift in our attitude toward urban
  water management is needed
• We must view urban stormwater as an asset, not a
  liability
• Design of stormwater management facilities must
  address the entire flow frequency curve
• We must maximize the management of runoff on-site

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Thank You