LOW IMPACT DEVELOPMENT AND INFILL DEVELOPMENT

APPLICATIONS

INFILL DEVELOPMENT SUMMITAUGUST 10TH AND 31ST, 2012

Suzanne B. ScottSARA General Manager

“States report that nonpoint source pollution is the leading remaining cause of

water quality problems.”EPA

http://www.epa.gov/owow_keep/NPS/whatis.html

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In 2020, San Antonio’s natural resources and environmental sustainability strategy “is based on an integrated approach that establishes a green economy and focuses on three key areas”:

●Water●Energy●Land: “Development practices are focused on Smart Growth, Low Impact Development and Green Building.”

SA 2020, City of San Antonio, March 19, 2011

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LAND USES THAT REDUCE RUNOFF

● Low Impact Development (LID)

● Green Infrastructure (GI)

● Water Harvesting

● Structural BMPs

Tucson, AZ

Slow It Down, Spread It Out, Soak It In

LID● Matches pre-development hydrology (on-site

management of stormwater)● Does not alter downstream and instream flow conditions● Addresses stormwater quality and quantity issues

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Green roof and permeable surfaces slow down and reduce rainfall runoff at a James Madison High School Agriscience Magnet Program building in San Antonio

Rain garden and curb cuts capture, slow, and polish street runoff; may be paired with under drain to convey larger flows after polishing first-flush

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GREEN INFRASTRUCTURE (GI)

Networks of multi-functional open spaces, including

●formal parks ●gardens ●woodlands●green corridors ●waterways ●street trees ●open countryside

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Plan for it and link it, as with gray infrastructure.

WATER HARVESTING

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• Reduces runoff• Provides first-flush polishing of roof water• Can be used to irrigate plantings

LID AND STRUCTURAL BMPS

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Pueblo. Porous pavers and a collection system below the parking lot http://urbanlandscapes.info/2010/05/03/low-impact-development-xeriscape-shouldnt-they-be-a-prerequisite-in-the-southwest/

Tree Box Filterhttp://www.lid‐stormwater.net/treeboxfilter_home.htm

TREATMENT TRAIN

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LID IN URBANIZED AREAS

Urban sprawl consumes green space and promotes auto dependency.

●Smart growth strategies are designed to reconfigure development in a more eco-efficient and community oriented style.

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● LID addresses many of the environmental practices that are essential to smart growth strategies including the conservation of open green space.

http://water.epa.gov/polwaste/green/

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LID IN URBANIZED AREAS● LID is compatible and often paired with complete

streets; often utilizes portions of excess right of way.

● LID provides opportunities to retrofit existing highly urbanized areas with pollution controls.

http://www.bing.com/images/search?q=Low+Impact+Development+Images&qpvt=Low+Impact+Development+Images&FORM=IGRE;

LID IN URBANIZED AREAS

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● Stormwater can easily be directed into rain barrels and vegetated areas in high-density urban areas.

● Urban areas may design bioretention systems into parking lots with little or no reduction in parking space.

● Vegetated rooftops and permeable pavements reduce impervious cover in highly urbanized areas.

LID IN URBANIZED AREAS

● LID can be adapted to a variety of lot sizes.

● Pairing structural BMPs with LID may be needed to achieve watershed objectives.

● LID effectiveness depends on site conditions and is not based strictly on space limitations.

● Soil permeability, slope and water table depth must be considered in LID design.

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http://www.bing.com/images/search?q=Low+Impact+Development+Photos&view=detail&id=18D0C65F88FECD7D79ED18FA085E9B2B2E958861&first=106

http://water.epa.gov/polwaste/green/

LID IN URBANIZED AREAS

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Development rules will need to be modified to promote/incentivize LID and reduce impervious cover. These rules ●include subdivision codes, zoning regulations, parking and street standards and other local ordinances that regulate development●are often responsible for wide streets, expansive parking lots and large-lot subdivisions that reduce open space and natural resources and/or increase impervious cover.

http://www.completestreets.org/webdocs/factsheets/cs-greenstreets.pdf

ADVANTAGES OF LID/GI

16 http://www.bing.com/images/search?q=Permeable+Pavers+On+Streets&view=detail&id=D1BF0A2652C8E939491905E8EC687FD0B7B528ED&first=106

LID/GI CHALLENGES● More complex design process● Requires increased construction oversight● Requires land owner education for private facilities● Structural BMPs and/or amended soils paired with

LID may be required in heavily urbanized areas with limited green space

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WHO TO RESEARCH AND WATCH

National Complete Streets Coalition on-line newsletter

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WHAT BRWM & SARA ARE DOING

● Pre-design Sustainability Matrix● 2012 Bond Project

– Pre-design BMP assessments– RFP scope recommendations

● San Antonio Land / Water Sustainability Forum

– LID education outreach – Design competition

● Code Reviews– UDC– TCEQ– SAWS

● LID Evaluation and Design Manual

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CONTACT INFORMATION● Karen Bishop, Sustainable Watersheds Program Leader

– (210) 302-3642; kbishop@sara-tx.org

● Steve Graham, P.E., CFM, SARA Assistant GM

– (210) 302-3622; sgraham@sara-tx.org