Presentation on theme: "Evaluating Stormwater BMPs Frank Henning Region IV Land Grant Universities Liaison Insert Unit # and Title."— Presentation transcript:
Evaluating Stormwater BMPs Frank Henning Region IV Land Grant Universities Liaison Insert Unit # and Title
What Low Impact Development Is and Is Not LID Is:LID Is Not: Volume control for small stormsMajor flood control Better stormwater management for new & existing development Anti-development Requires complementary approaches for large storms A stand-alone solution for all wet weather management Scale site specific solutionOne size fits all Mimics natural hydrologyDry up all the streams Cost competitive to traditional stormwater management Free
Green Infrastructure/LID – Preserves natural environments – Retains stormwater volume for infiltration, evapotranspiration, or use – Removes the volume from the stream – Mimics natural hydrology, often enhances groundwater recharge and base flow – Removes pollutant load associated with the volume retained – Does not transfer pollution to ground water – May need additional storage to address stream protection and flood prevention requirements
Natural Area Preservation Storage volume = predevelopment conditions Natural areas generally are counted as net zero Can they store, infiltrate, evapotranspirate more than the design volume? Soils and vegetation – already present = free Inlet/Outlet control – direct inflow/overland flow = free Wetlands Franklin, TN Maryville TN Buffers Maryville TN Springhead
Soil Enhancement Program Cost – usually minimal or low Storage – enhance void space and infiltration rate of soil Soil – amended soil and native soil infiltration rate Vegetation – selection based on site Inlet/Outlet – direct inflow, overland or directed
-Proper fertilizer and pesticide use -Maintain vegetative cover -BMP is a nutrient sink, not a nutrient source (how green is green?) -Stormwater contains nutrients Reduce Pollutant Loads
Disconnection Programs Storage – based voids, and infiltration rate of soil, impervious area disconnected (capture area) Soils – amended or uncompacted native soil Vegetation – selection based on the site Inlet/Outlet – downspouts, sheet flow over vegetated areas to swales, sewers, waterbodies
Tree Canopy Programs Storage volume - based on pool volume, void space of amended soil, native soil infiltration rate, evapotranspiration rate, capture area Soil – structural or amended for storage/pollutant uptake Vegetation - trees for largest amount of evapotranspiration, other benefits Inlet /Outlet Controls – must provide!
Rainwater Harvesting & Use Storage volume – Water Use – irrigation or other use Soils - infiltration Vegetation – evapotranspiration Inlet/Outlet - must be provided Outlet protection – reduce erosion
Green Roofs Storage – soil depth/voids Soils – amended, structured Vegetation – intensive (shallow soil- sedums or drought tolerant species) or extensive (deep soil-small tree, shrubs) Inlet /Outlet – direct capture/roof drains Structural – must perform analysis
Raingardens/Bioretention Storage Volume – based on pool design, amended soil void space, capture area Soils - native soils are removed and replaced with amended soil Vegetation - herbaceous (low evapotranspiration) Inlet/ Outlet controls - direct inflow and provide for bypassing larger events
Other GI/LID Benefits Air quality improvement Community beautification Energy savings Health benefits Heat island reduction Property value improvement Recreation and wildlife
Acknowledgements Module contributors: Material for this module was adapted from presentations and publications by Region IV EPA Watershed Protection Division Module editors: [Insert names and affiliations here for at least 2 peer-reviewers] Southern Region Landscape Team: Amy Shober (UF/IFAS); Lucy Bradley (NCSU); Eve Brantley (Auburn); Wendi Hartup (NCSU); Barbara Fair (NCSU); Frank Henning (USEPA/UGA); Esen Momol (UF/IFAS); Kerry Smith (Auburn); Dotty Woodson (Texas Agrilife); Sheryl Wells (UGA) Funding for this module provided by: USDA-NIFA National Water Program, Southern Regional Water Program special project funds Graphic design: Emily Eubanks - UF/IFAS Center for Landscape Conservation and Ecology; Amy L. Shober – UF/IFAS Gulf Coast Research and Education Center 21
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