Environmental Criteria Manual Environmental Criteria Manual Updates: Updates: Innovative Stormwater Innovative Stormwater Controls Controls Michael Kelly, P.E. John Gleason, Landscape Architect Watershed Protection Watershed Protection and Development and Development Review Department Review Department
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Texas; Innovative Stormwater Controls - Austin Energy
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Michael Kelly, P.E.John Gleason, Landscape Architect
Watershed Protection Watershed Protection and Development and Development Review DepartmentReview Department
ECM 1.6.7 Innovative Water Quality ECM 1.6.7 Innovative Water Quality ControlsControls
•• Vegetative Filter Strips (VFS)/ VFS Vegetative Filter Strips (VFS)/ VFS –– Disconnection of Imp. CoverDisconnection of Imp. Cover
•• BiofiltrationBiofiltration
•• Rainwater HarvestingRainwater Harvesting
•• Porous Pavement for Pedestrian UsePorous Pavement for Pedestrian Use
•• Rain GardensRain Gardens
Presenter�
Presentation Notes�
The City of Austin uses a multiple solutions approach toward watershed protection. We create and implement regulations such as water quality ordinances that require land developers to build stormwater runoff ponds whenever they build. The SOS Save Our Springs Ordinance is the strictest of those, and it takes a ‘no degradation’ approach to water quality. We require stream setbacks and water quality zones for all of our local streams and rivers. Programs include a community education program called “Grow Green”, which is a partnership between the City of Austin and the Texas Cooperative Extension Service of Travis County. This program provides integrated pest management (IPM) information at the various local stores that sell landscape chemicals. Other programs include monitoring of water chemistry and biology in our creeks, a spills response program, and so on. The third primary technique we use for watershed protection is the use of CIP’s, or Capital Improvement Projects. And that is what I’d like to explain in some detail. �
OnOn--site Stormwater Treatmentsite Stormwater TreatmentSedimentation/Filtration: standard water quality treatment pondSedimentation/Filtration: standard water quality treatment pond
Presenter�
Presentation Notes�
Land developers are required to build a sedimentation/filtration pond (aka sand filter) for stormwater runoff in the City of Austin. A potential substitute for the sand filter is a wet pond. A wet pond is a stormwater pond with a permanent pool of water. One advantage that a wet pond has over a sand filter is apparent at first glance… they look better!�
•• Plants must tolerate wide variations in moisturePlants must tolerate wide variations in moisture•• Total Plants: Surface area (Total Plants: Surface area (s.fs.f.) of pond bottom .) of pond bottom
x 0.1x 0.1•• Sedimentation basin: Min. 20% of total plantsSedimentation basin: Min. 20% of total plants
•• Trees are allowedTrees are allowed•• Filtration basin: Min. 50% of total plantsFiltration basin: Min. 50% of total plants
•• Min. 20% tall herbaceousMin. 20% tall herbaceous•• No more than 30% medium herbaceousNo more than 30% medium herbaceous•• No trees are allowedNo trees are allowed
BiofiltrationBiofiltration at at TechRidgeTechRidge
Rainwater HarvestingRainwater Harvesting
HEB Brodie Lane
Rainwater Harvesting: Option ARainwater Harvesting: Option ACaptured Runoff discharged to a VFS for infiltration (<72 hr)Captured Runoff discharged to a VFS for infiltration (<72 hr)
Rainwater HarvestingRainwater Harvesting1. Captures runoff to be used for other
beneficial purposes.
2. Capture volume can be sized to meet watershed specific requirements (e.g. Urban vs. SOS); requires adequate infiltration or irrigation field for ultimate disposal of stormwater
3. May be upsized to provide water conservation function.
Rainwater Harvesting: Option ARainwater Harvesting: Option ACaptured Runoff discharged to a VFS for infiltration (<72 hr)Captured Runoff discharged to a VFS for infiltration (<72 hr)
Rainwater Harvesting:Rainwater Harvesting: Option AOption A
Rainwater Harvesting: Option BRainwater Harvesting: Option BCaptured Runoff Used to Irrigate Vegetated AreaCaptured Runoff Used to Irrigate Vegetated Area
Conveyance system
• Max. 72 hr. drawdown time
• Use retentio/irrigation criteria (ECM 1.6.7A)
• Allowable in the Barton Springs Zone
Rainwater Harvesting: Option BRainwater Harvesting: Option BCaptured Runoff Used to Irrigate Vegetated AreaCaptured Runoff Used to Irrigate Vegetated Area
Tank
Sprinkler system (per retention/irrigation criteria)
Porous Pavement for Pedestrian Use Porous Pavement for Pedestrian Use