RAINWATER HARVESTING
A significant portion of stormwater runoff is generated from buildings and structures . Conventional methods to handle this runoff involve the use of downspouts which divert water away from structures and their foundations . Another alternative is to capture the runoff from roofs and store it for later use . Rainwater harvesting allows for the capture , diversion , and storage of rainwater for future use . This ancient practice involves the collection of rainwater from impervious surfaces , enhancing its ability to benefit the environment and nearby landscape rather than simply attempting to remove it from the site . The collected rainwater can also be used for landscape irrigation , and other non-potable purposes .
RAINWATER HARVESTING
The three components of a traditional rainwater harvesting system are 1 ) collection , 2 ) storage , and 3 ) use . Collection typically comes from rooftops or paved surfaces . The collected water is then transported through downspouts to a temporary storage site for future use . These sites can consist of either above or below ground runoff containment devices . They collect rainwater directly from impervious surfaces , and hold them for future dispersion or use . Storage devices come in varying forms including rain barrels , cisterns , and bladder tanks . Typical components of a rain catchment system include ( UGA Extension ):
1 . the catchment surface ( normally a roof ), which serves as the rainwater collection component , 2 . gutters and downspouts , which direct the water from the roof to the tank , 3 . a basket filter or leaf screen to reduce debris from captured rainwater before it goes to the tank 4 . vessels to store harvested rainwater , 5 . a pump if pressure from gravity is not adequate , and 6 . a delivery system such as outlet pipes , hoses or vents .
Water from these systems should be utilized for non-potable applications such as irrigation . For aesthetic purposes , these systems can be covered by a wooden structure and painted to match the color of nearby structures or to blend into the surroundings .
There are a variety of containment devices which can be used to store stormwater runoff for later use . These are generally dependent on the space available for the device , the volume of expected runoff , and aesthetics of the site . As a general rule , a one-inch rain event on one-square foot of impervious surface produces around 0.623 gallons of water . For example , a 1000 square-foot roof can yield approximately 623 gallons of water during a 1-inch rain event ( Clemson Extension HGIC , 2015 ). The tank will have an overflow where water can exit the tank when it is full , the overflow should be directed away from the footprint of nearby structures . All of the storage types can be outfitted with a spigot for use in irrigation or to slowly release water .
Rain Barrels
These storage devices sit above ground and collect runoff from a roof through a connected downspout . Rain barrels are commercially available , or could be built using food grade materials . Rain barrels have a typical capacity of 55- 100 gallons which limits the amount of water storage capacity . However , multiple rain barrels can be connected to collect additional water . These connections can be connected to a central spigot and release valve to release the collected water for irrigation and other uses for non-potable water . In multiple barrel systems , connections can be made between the barrels to provide an even distribution of collected rainwater . Filtered air release openings should be installed on barrels to allow the system to evenly distribute water .
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