Transcript Low Impact Development They took all the trees and put them in a tree museum and they charged all the people a.

Low Impact Development
They took all the trees and put them in a tree museum and they charged all
the people a dollar and a half just to see 'em. Don't it always seem to go that
you don't know what you've got till it's gone? They've paved paradise and
put up a parking lot.”
Joni Mitchell
TABLE OF CONTENTS
• Development and Storm Water Runoff
• Storm Water Pollutants
• Low Impact Development (LID)
• Goals
• Benefits
• Common Practices
Development and Storm Water Runoff
40% evaporation
38% evaporation
20%
runoff
10%
runoff
25% shallow
infiltration
25% deep
infiltration
Natural Groundcover
21% deep
infiltration
10 - 20% Cover
30% evaporation
35% evaporation
55%
runoff
30%
runoff
20% shallow
infiltration
21% shallow
infiltration
15% deep
infiltration
35 – 50 %l Cover
10% shallow
infiltration
5% deep
infiltration
75 - 100% Cover
Storm Water Pollutants
• Not treated – Flows directly to nearest
stream
• Picks up pollutants
–
–
–
–
–
Sediment
Pathogens
Nutrients
Toxic contaminants
Debris/litter
©iStockphoto.com
Low Impact Development (LID)
A storm water management approach
that uses green space, native
landscaping, and other techniques to
reduce the volume of and improve the
quality of storm water runoff.
Goals of LID
• Mimic predevelopment hydrology
• Reduce storm water runoff and pollution
– Store
– Treat
– Infiltrate
EPA
Benefits
• Effective
• Economical
• Flexible
• Adds value
Common LID Practices
•
•
•
•
•
•
•
Rain gardens and bioretention
Rooftop gardens
Vegetated swales, buffers, and strips
Rain barrels and cisterns
Permeable pavers
Permeable pavement
Impervious surface reduction
Common LID Practices
• Rain gardens and bioretention
Image by the Environmental Protection Agency
Common LID Practices
• Green roof
Image by the Environmental Protection Agency
Courtesy Eric Fisher
Common LID Practices
• Vegetated swales, buffers, and strips
Courtesy Eric Fisher
Image by the Environmental Protection Agency
Common LID Practices
• Rain barrels and cisterns
©iStockphoto.com
Common LID Practices
• Permeable pavers
Image by the Environmental Protection Agency
Common LID Practices
• Permeable pavement
Image by the Environmental Protection Agency
Common LID Practices
• Impervious surface reduction
©iStockphoto.com
Conventional Versus LID Site Design
Conventional
Site Design
Low Impact Development
Site Design
LID Commercial Design
Image by the Environmental Protection Agency
LID Commercial Design
Image by the Environmental Protection Agency
Image by the Environmental Protection Agency
TABLE OF CONTENTS
• Development and Storm Water Runoff
• Storm Water Pollutants
• Low Impact Development (LID)
• Goals
• Benefits
• Common Practices
Resources
Bioretention.com: An online reference for designers. (n.d). Retrieved Dec.
15,2009 from http://www.bioretention.com/
Department of Environmental Resources of Prince George’s County,
Maryland. (1999). Low-Impact Development Design Strategies –An
Integrated Design Approach. Retrieved December 15, 2009, from
http://www.lowimpactdevelopment.org/pubs/LID_National_Manual.pdf
Environmental Protection Agency. (n.d). Stormwater management best
practices. Retrieved December 15, 2009, from
http://www.epa.gov/greeningepa/stormwater/best_practices.htm#per
meablepavers
Low Impact Development Center, Inc. (n.d.). Urban design tools. Retrieved
December 15, 2009, from http://www.lid-stormwater.net/index.html
Low Impact Development