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Rainwater Harvesting
Janie HarrisExtension Specialist
Housing and Home EnvironmentTexas AgriLife Extension Service
Efficient Water Use is Critical• Limited water supply• Growing population• Rainwater catchment is a source of
water• Water will not always be inexpensive
P Increased Demand for a Decreasing SupplyP Rising Environmental & Economic CostsP Rainwater’s PurityP Conservation – Saving Your Water!P Reduce Runoff – Crucial in CitiesP Droughts have Increased Need & AwarenessP Water for Areas w/o Groundwater or Service
Why Collect Rainwater?
Cisterns - The only source of water for many before electricity and well drillers
Increased Impervious Areafrom pavement & roofs
Value of Rainwater
Low pH 6.0 to 7.0
High quality water
Makes You Conservation Minded
Free
P Attract and provide water for wildlife, pets, birds and butterfliesP Landscape irrigation, house plantsP In home use – laundry, bath/shower, drinking, cleaning, etc.
Rainwater Uses
How to Catch Rainwater
* Roof – Sloped Tin is best but any will work* .6 gallons per square foot roof* 2,000 sq. foot roof X 1" rain = 1,200 gal. water* 1,200 gal. X 20" rainfall per year= 24,000 gal/yr.* 12” rain yields 14,400 gals./yr.* 6” rain yields 7,200 gals./yr.
P Gutters - Nothing special P Roof washers - removes trash, debris & dust
Gutters and Roof Washers
Screens to Keep Out Trash & Mosquitoes
P Durable and water tight – materialP OpaqueP Size – depends on how much you will collect and need and where the water will be usedP Cost - $ .30 - 1.25 per gallon collected
Cisterns or Tanks for Storage of Water
Small Rain Barrels
Simple Rain Barrel w/Gutter
Selection – Size, Color, Shape
P Gate valve and facets
The Other Parts
The clear plastic hose allows water to rise to the
level the water is inside the tank
Water Gauge
Overflow allows water to run out of tank when full rather
than backing up
into the gutter of this
Rain Barn
Overflow Pipe
Pump and Pressure Tank
Filters and Sanitizers – Drinking H2O
P Drip irrigation – Landscape or GardenP Water garden in groundP Wildlife and pet waterP Sprinklers, misters & watering with pressureP In home uses
Distribute Water to Desired Location
Rainwater can be used in a water feature with floats that keep the water
level high enough to run reciprocating pumps.
Water Features in Landscape
Rainwater Harvesting
• Rainwater harvesting captures, diverts and stores rainwater for later use.
• Easiest use is for landscaping irrigation• Can be used for household use with proper
treatment.• Rainwater is good for plants because it is
free of salts and other minerals
Rainwater Harvesting
• Reduces the demand for chlorinated or other chemically treated tap water therefore you buy less water
• Reduces the amount of water that will go into storm sewers where it is mixed with oil and other toxic residues from streets, parking lots etc.
Resources
• Rainwater Harvesting – B-6153 Texas AgriLife Extension Service, TAMUShttp://agrilifebookstore.org/publications_details.cfm?whichpublication=1979 $4.50
• Texas Guide to Rainwater Harvesting, Texas Water Development Boardhttp://www.twdb.state.tx.us/assistance/conservation/Alternative_Technologies/Rainwater_Harvesting/Rain.asp