Protecting Floodplains and Water Quality through LID

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Protecting Floodplains and Water Quality through
LID

• Dov Weitman
• Chief, Nonpoint Source Control Branch
• U.S. Environmental Protection Agency
• Presented at ASFPM Conference
• June 9, 2009
• [phone]
• weitman.dov_at_epa.gov

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An Opportunity to Work Together

• Floodplain managers and water quality managers
  have a lot in common.
• We both want to prevent flooding, and we both
  want to protect water resources and water
  quality.
• We each emphasize different aspects of this issue
  in our work, but our work supports each other.
• I hope to demonstrate in my short talk that we
  have a great opportunity to work together on an
  important issue at the intersection of these two
  mutual interests.

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Floodplain Managers Interest

• ASFPM Position Paper, Natural and Beneficial
  Functions Floodplain Management More than
  Flood Loss Reduction (Sept. 16, 2008)
• We need to protect natural functions of
  floodplains and coastal areas
• We are concerned about the increased
  urbanization and alteration of the flooding
  process
• These interrupt natural processes and thus
  disturb the overall health of the ecosystem

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ASFPM No Adverse Impact

• ASFPM promotes NAI Floodplain Management Do not
  allow actions of one property owner to adversely
  affect the rights of other property owners
• Designed to reduce flood damage and encompass
  related objectives such as water quality
  protection, groundwater recharge, or the
  management of stormwater, wetlands, and riparian
  zones.

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EPA Protect Water Quality

• New Initiative to Protect Healthy Watersheds
• www.epa.gov/healthy/watersheds
• Protect wetlands, riparian areas, floodplains and
  other natural areas needed to protect water
  quality
• Preserve natural processes (hydrology,
  geo-morphology, hydro-ecology, landscape)

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But Where Development Occurs

• Our task is to assure that development and
  redevelopment protect water quality.
• Regarding urban development, our thinking has
  evolved just like ASFPMs approach has evolved.
• Heres what we now think

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Its the Hydrology, Stupid! (adapted from James
Carville, 1992)

• The volume of water resulting from rainfall (too
  much or too little) is the most significant
  source of WQ problems in urban/suburban areas.
• The root causes are rain landing on impervious
  surfaces having nowhere to go except directly to
  the nearest stream or sewer.
• When it rains, the stream gets too much water.
• When its not raining, the stream doesnt get
  enough water.

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What Happens When it Rains

• In the absence of development, rain falls on
  forestland, farms, rangeland, pastures, etc.
• More than 90 infiltrates into the ground or
  evapotranspires less than 10 runs off directly
  to the streams.
• Much of that ground water feeds rivers streams.
• Many streams get most of their water from GW (US
  FS-150-99)

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Post-development Feast or Famine
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Post-development Feast or Famine

• Two problems result from the modification of
  hydrology shown on the previous slide
• Storm events where the flow is much higher after
  development, causing stream scouring, transport
  of sediment, etc.
• Unnaturally low flows between storm events,
  reducing and sometimes eliminating fish and
  macro-invertebrates, as well as raising temp.

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Healthy Watershed
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• 8-10 Imperviousness

The stream shows signs of stress, with exposed
tree roots and river banks that are significantly
eroded streambed is sedimented
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10 Imperviousness
At 10 impervious cover, the stream is slightly
more visibly impacted. The stream shown here has
approximately doubled its original size, tree
roots are exposed, and the pool and riffle
structure seen in sensitive streams is lost.
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20 Imperviousness
Suburban streams often will exceed 20, with
roads, driveways and houses. The stream sediment
is primarily from its own banks, eroded by the
force of water
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• Also 20 Imperviousness

The surrounding area of this stream is also
approximately 20 impervious cover and shows
stream erosion that is much worse than in the
previous slide due to an absence of vegetation to
hold together bank structure.
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Green Infrastructure at the Neighborhood Scale

• Less imperviousness! More vegetation!
• (This promotes infiltration and
  evapotranspiration)
• Narrower streets, narrower or fewer sidewalks,
  smaller-footprint buildings, plant trees
• Read Better Site Design, Center for Watershed
  Protection, www.cwp.org

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Conventional
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Low Impact Development

• Systems and practices that use or
• mimic natural processes to
• Infiltrate
• Evapo-transpirate, or
• Reuse
• stormwater or runoff where it is generated.

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Disconnectivity (from the sewer system)
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Porous Concrete
Villanova University, To date, has captured and
infiltrated runoff from all storms up to 2
inches (Dietz). (Note project funded with PA
Section 319 funds.)
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Rain Gardens
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Seattles Street Edge Alternatives Program
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The Thirst of Trees

• One tree can reduce SW runoff by 13,000 gallons
  per year. 500,000 existing trees in NYC can
  remove 6.5 billion gallons per year. Adding
  300,000 more will remove an additional 3.9
  gals/yr. (Sustainable Raindrops).
• NYC Citys annual Combined Sewer Overflow is 27
  billion gallons.

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Summary of LIDs Benefits

• Reduce pollution and destruction of
  streams/streambanks
• Reduce downstream flooding/Protect downstream
  water resources and properties
• Reduce incidence of combined sewer overflows
• Recharge ground water
• Reduce costs to collect treat stormater (e.g.,
  fewer or smaller storm sewers)
• Improve Habitats and Communities

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Wait, Wait, Theres More!

• Enhance aesthetic value
• Enhance real estate value/property tax revenue
• Increase lot yield (fewer ponds need to be built)
  
• (win/win/win for developer/community/owner
• Enhance public spaces/quality of life

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Cost Savings of LID

• Reducing Stormwater Costs through LID
  Strategies and Practices.
• www.epa.gov/nps/lid/costs07
• 17 case studies in the great majority of cases,
  the LID scenario was cheaper than the traditional
  conventional treatment approach.

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Summary of Cost Comparisons
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How did LID Save Money?

• Primarily through costs avoided/reduced thanks to
  the implementation of LID Practices
• Eliminate or reduce stormwater ponds
• Eliminate or reduce storm sewer pipes
• Reduce stormwater or sewer overflow storage
• Reduce other hard infrastructure
• Narrower streets
• Less sidewalk
• Reduce stormwater treatment devices
• Avoid land purchase for ponds, etc.
• Use saved land to build more lots

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LID is Breaking Out All Over

• Federal support and even pressure has grown to
  promote LID implementation
• Many States and Cities have passed laws or
  ordinances, and created economic incentives, to
  promote LID

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Navy Directive

• Conventional storm water collection and
  conveyance system and SW treatment options do not
  and can not replicate natural systems, thus
  increasing the volume and flow of SW
• Goal No net increase in SW volume and sediment
  and nutrient loadings.
• LID must be implemented.
• Assistant Secretary of the Navy Penn memorandum
  (November 16, 2007)

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Energy Independence and Security Act of 2007

• Sec. 438. Storm Water Runoff Requirements
  for Federal Development Projects. The sponsor of
  any development or redevelopment project
  involving a Federal facility with a footprint
  that exceeds 5,000 square feet shall use site
  planning, design, construction, and maintenance
  strategies for the property to maintain or
  restore, to the maximum extent technically
  feasible, the predevelopment hydrology of the
  property with regard to the temperature, rate,
  volume, and duration of flow.

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LEED-Neighborhood Development

• Will provide points for practices that reduce
  flow volume
• It is anticipated that other LEED standards
  (e.g., LEED-NC) will be modified to include
  similar Stormwater credits

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Sustainable Sites Initiative

• Led by the American Society of Landscape
  Architects
• EPA is a proud participant
• LID is a key component of the SSI
• www.sustainablesites.org

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North Carolina

• November 19, 2008 NC Regulation
• Applies to under-1 acre development.
• If 10,000 sq. ft. are disturbed, 1 ½ inches must
  be controlled on site.
• Preferred option Cisterns and rain barrels, or
  rain gardens, collect all rooftop water, and all
  other surfaces are pervious.

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Washington DC Anacostia Redevelopment Standards

• Retain first inch of rainfall for new development
  and redevelopment.
• Vegetated controls (green roofs, rain gardens,
  biofilters, swales, pocket wetlands, large
  filtered cells for growing trees) are the
  preferred approach that must be considered
  first.
• Permeable pavements, infiltration trenches, etc.
  are the second allowed choice.

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Other Cities/States with Stringent Controls

• Maryland, NJ, California, Minnesota
• Philadelphia
• San Diego and Ventura counties, CA
• Knox County, TN
• Portland, OR
• Stafford County, VA
• New York City
• Lenexa, Kansas

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Next Round of Stormwater Permits

• As NPDES stormwater Phase I and II permits are
  issued, look for a renewed focus on upgrading
  them to address volume.
• TMDLs are likewise addressing flow in many
  states, including Vermont, Maine, and Connecticut.

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Philadelphia

• 50 discount in stormwater fee for residents and
  businesses.
• Credit for decreasing directly connected
  impervious areas using specified practices (rain
  gardens, infiltration islands, porous asphalt and
  sidewalks, vegetated swales, green roofs).
• Revising fee structure to be based on impervious
  area, and setting fees at level that will drive
  most sizeable buildings and parking lots to
  reduce imperviousness.

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Minneapolis

• Up to 50 credit for practices that address
  stormwater quality
• 50 or 100 credit for practices that address
  stormwater quantity
• 10-year (50) or 100-year rain event (100)

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Problems

• Water Quality
• Como Lakeimpaired water
• Drainage areaentirely urbanized
• Flooding
• Neighborhood flooding
• Conveyance (undersized pipe in Golf Course)
• Residential Streets
• In need of and scheduled for repair in 2005-06
• Intercommunity Flow
• Drainage from 3 Cities and County property
  Cost Share needed
• Aging sewers need repair

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Poor Water Quality in Lake Como
CRWD
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Localized Flooding
CRWD
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Original Solution

• Add a tandem 60 pipe through Como Park
  Estimated 2.5 million
• Severe disruption to the Park
• No improvements to stormwater runoff to Como Lake

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Selected Solution Volume Reduction

• Address flooding and water quality
• Install infiltration trenches
• Construct rain gardens
• Final Cost 1.4 million

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Golf Course pond retrofit included a diversion
pipe to reduce costs
CRWD
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A Place to Start

• Each of EPAs Regional offices has a Nonpoint
  Source Coordinator.
• Every State also has a NPS Coordinator.
• Click on Contact Us at the top of our home
  page www.epa.gov/nps for addresses, phone
  numbers and email for all of the above.

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Conclusion

• Low Impact Development is Win-Win for the Flood
  Control and Water Quality Communities.
• To learn more, come to EPAs session tomorrow,
  100 500, LID Managing Wet Weather with
  Green Infrastructure, led by Lisa Hair of EPAs
  Nonpoint Source Control Branch.

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Resources

• EPAs Green Infrastructure Website
• www.epa.gov/greeninfrastructure
• EPAs NPS and LID Websites
• www.epa.gov/nps and www.epa.gov/nps/lid
• Low Impact Development Center
• www.lowimpactdevelopment.org
• An excellent commercial (with a hippie attitude)
  green roof website
• www.greenroofs.com
• Wisconsin DNR Rain Garden Manual
• www.dnr.state.wi.us/org/water/wm/nps/rg/index.htm
  

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More Resources

• Reducing Stormwater Costs through LID Strategies
  and Practices
• www.epa.gov/nps/lid
• Better Site Design, by Center for Watershed
  Protection
• www.cwp.org
• Abby Halls LID Slides (currently includes 391
  slides from 11 cities)
• http//picasaweb.google.com/buildgreeninfrastruct
  ure