stormwater management
DESCRIPTION
Stormwater Management. For Developing Municipalities. What Residents Can Do What Towns Can Do. ACKNOWLEDGEMENTS. CENTER FOR WATERSHED PROTECTION, www.cwp.org www.stormwatercenter.net Tom Schueler, Director of Watershed Research and Practice at CWP - PowerPoint PPT PresentationTRANSCRIPT
Stormwater Management
For DevelopingMunicipalitiesWhat Residents
Can Do
What Towns Can Do
ACKNOWLEDGEMENTS
• CENTER FOR WATERSHED PROTECTION, www.cwp.org
• www.stormwatercenter.net
• Tom Schueler, Director of Watershed Research and Practice at CWP
• NEMO PROGRAM - University of Connecticut, http://nemo.uconn.edu/
Development Impactson the Water CycleDevelopment ImpactsDevelopment Impactson the Water Cycleon the Water Cycle
50%50%50%10%10%10%
15%15%15%55%55%55%
Development Means Less Infiltration
Nutrients Pathogens Sediment Toxic Contaminants Debris Thermal Stress
NutrientsNutrients
PathogensPathogens
SedimentSediment
Toxic ContaminantsToxic Contaminants
DebrisDebris
Thermal StressThermal StressIncreased quantityIncreased quantity
Decreased qualityDecreased quality
Development Impacts on Water QualityDevelopment Impacts on Development Impacts on Water QualityWater Quality
NutrientsPathogensSedimentToxic ContaminantsDebrisThermal Stress
Waterway Health & Waterway Health & ImperviousnessImperviousness
Waterway Health & Waterway Health & ImperviousnessImperviousness
ADAPTED FROM SCHUELER, ET. AL., 1992ADAPTED FROM SCHUELER, ET. AL., 1992
8080
7070
6060
5050
4040
3030
2020
1010
00
STREAM DEGRADATIONSTREAM DEGRADATION
WA
TE
RS
HE
D I
MP
ER
VIO
US
NE
SS
WA
TE
RS
HE
D I
MP
ER
VIO
US
NE
SS
(%)
(%)
DEGRADED
PROTECTED
IMPACTED
Waterway Health Declines
Imperviousness Increases
MUNICIPAL ACTION
• Public Works – Streets– Playing Fields and parks– Stormwater sewer
system
• New Development– Planning– Zoning– Maintenance
Culvert and Outfall
Opportunity for Retrofit
Scenario for erosion
STORMWATER MANAGEMENT ORDINANCE
For New Development
Groundwater Recharge Requirement
• Maintain Existing (100%) Average Annual Groundwater Recharge post development
OR
• Infiltrate the Post Development Increase in the 2-year Storm •
Nonstructural SWM Strategies
• Protect areas that provide water quality benefits
• Minimize & Separate Impervious Cover
• Maximize protection of natural drainage features and vegetation
• Minimize Disturbance
• Minimize Reduction in Time of Concentration
• Minimize soil compaction
(should be in municipal ordinance)
• Provide Low-maintenance Landscaping and use of native vegetation
• Provide Opportunities for Reduction of Pollutants at the Source – Trash Racks and Receptacles
– Minimize Vegetation That Needs Fertilizers
– Use Native Plants
• Manage stormwater runoff at source
LAND USE ORDINANCESESTABLISH DESIGN
STANDARDS