SAWS & Bexas Regional Watershed Management Low Impact & Infill Development Applications.

1. LOW IMPACT DEVELOPMENT
AND INFILL DEVELOPMENT
APPLICATIONS
INFILL DEVELOPMENT SUMMIT
AUGUST 10TH AND 31ST, 2012
Suzanne B. Scott
SARA General Manager

2. “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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3. 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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4. LAND USES THAT REDUCE RUNOFF
Slow It Down, Spread It Out, Soak It In
● Low Impact Development (LID)
● Green Infrastructure (GI)
● Water Harvesting
● Structural BMPs
Tucson, AZ

5. LID
● Matches pre-development hydrology (on-site
management of stormwater)
● Does not alter downstream and instream flow conditions
● Addresses stormwater quality and quantity issues
Green roof and permeable surfaces slow down
and reduce rainfall runoff at a James Madison Rain garden and curb cuts capture,
High School Agriscience Magnet Program slow, and polish street runoff; may be
building in San Antonio paired with under drain to convey
5 larger flows after polishing first-flush

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7. GREEN INFRASTRUCTURE (GI)
Networks of multi-functional open spaces, including
●formal parks
●gardens
●woodlands
●green corridors
●waterways
●street trees
●open countryside
Plan for it and link it, as with
gray infrastructure.
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8. WATER HARVESTING
• Reduces runoff
• Provides first-flush polishing of roof water
• Can be used to irrigate plantings
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9. LID AND STRUCTURAL BMPS
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 Filter
http://www.lid‐stormwater.net/treeboxfilter_home.htm
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10. TREATMENT TRAIN
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11. 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.
● LID addresses many of
the environmental
practices that are
essential to smart growth
strategies including the
conservation of open
green space.
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http://water.epa.gov/polwaste/green/

12. 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;
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13. LID IN URBANIZED AREAS
● 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.
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14. 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. http://www.bing.com/images/search?q=Low+Impact+Development+Photos&view=detail&id=18D
0C65F88FECD7D79ED18FA085E9B2B2E958861&first=106
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http://water.epa.gov/polwaste/green/

15. LID IN URBANIZED AREAS
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 http://www.completestreets.org/webdocs/factsheets/cs-greenstreets.pdf
impervious cover.
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16. ADVANTAGES OF LID/GI
16 http://www.bing.com/images/search?q=Permeable+Pavers+On+Streets&view=d
etail&id=D1BF0A2652C8E939491905E8EC687FD0B7B528ED&first=106

17. 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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18. WHO TO RESEARCH AND WATCH
Photo: Greg Raisman, flickr.com/photos/gregraisman
National Complete Streets Coalition on-line newsletter
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19. 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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21. CONTACT
INFORMATION Watersheds Program Leader
● Karen Bishop, Sustainable
– (210) 302-3642; kbishop@sara-tx.org
● Steve Graham, P.E., CFM, SARA Assistant GM
– (210) 302-3622; sgraham@sara-tx.org
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