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| US Department of Environmental Quality,
2002. |
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Description
Above or below ground tanks or barrels used to store water runoff from
impervious surfaces. Provide aquifer recharge with proper flow dispersal.
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| Texas Water Development Board, 2006. |
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Mechanisms
A reduction in water runoff is achieved through channeling flow to a
collection tank. Greater infiltration to groundwater occurs when proper
procedures are followed in dispensing the water over a pervious area. Spreading
the tank contents at an application quantity great enough to provide
infiltration but low enough to prevent runoff will increase infiltration.
Infiltration would also result from dispensing the flow to an area designed to
provide greater infiltration, such as a drainage trench. Note that rain barrels
are very effective as a water conservation practice.
Applications
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| Texas Water Development Board, 2006. |
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- Well suited for arid climates.
- Useful in reducing runoff contamination from roof tops, driveways, sidewalks
and other impervious surfaces.
- Requires area for water distribution or connection to supplemental systems.
- Only for use with low pollution concentrations.
- Requires pretreatment for screening and first flush diversion.
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| Texas Water Development Board, 2006. |
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Detailed Specifications
Design Values*:
- Install a pretreatment to separate sticks, leaves and debris.
- Sizing determined from impervious surface area, rain fall, infiltration
area, and operational strategy.
- Utilize gutters and downspouts to channel water flow to storage device.
- Install mechanism to discharge first flow.
- Install outflow devices compatible with desired irrigation or dispersal
mechanisms.
- Design overflow and freezing plans.
- Provide area for proper discharge of tank water.
Underground:
- Clear and excavate.
- Install level.
- Connect input and output.
- Backfill.
- For more information visit:
The Texas Manual on Rainwater Harvesting.
*Note: Local governments may use different design values
than those listed above, be sure to comply with any applicable laws and
regulations.
Plans
Texas Water Development Board, 2006.
Texas Water Development Board, 2006.
Water Quality
- Infiltration of runoff.
- Pollutant removal due to soil filtering processes.
Maintenance
- Remove debris from pretreatment device as needed.
- Clean tank annually.
- Inspect at least twice per year.
- Clear the inlet(s) and outlet(s) to allow for proper flow dispersal as
needed.
- Clean gutters as needed.
- Disperse flow to drainage area as often as design requires.
Resources
Milwaukee Metropolitan Sewerage District and Water Quality Initiative.
Cisterns.
http://www.mmsd.com/wqi/docs/factsheet_cisterns.pdf (February 20, 2006).
State of Ohio Environmental Protection Agency. August 5, 2005. Total Maximum
Daily Loads for the Euclid Creek Watershed. pp 41-42.
http://www.epa.state.oh.us/dsw/tmdl/Euclid Creek Final Report 080505.pdf
(February 2006).
Texas Water Development Board. 2006. The Texas Manual on Rainwater
Harvesting, Third Edition.
http://www.twdb.state.tx.us/publications/reports/RainwaterHarvestingManual_3rdedition.pdf
(February 2006).
United States Environmental Protection Agency. August 15, 2002. On-Lot
Treatment. Post-Construction Storm Water Management in New Development &
Redevelopment.
http://cfpub.epa.gov/npdes/stormwater/menuofbmps/index.cfm (February
2006).
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