Every day, untold billions of gallons of drinking water is used to water landscapes.
In desert areas, where native and drought-adapted plants thrive, water is a precious commodity.
That’s why rainwater harvesting makes sense.
It makes use of “free” water to irrigate gardens and landscapes. Using this “free” water reduces the stress on surface drinking water supplies such as reservoirs and rivers.
It also reduces the use of groundwater from aquifers and other underground supplies.
Other Benefits to Using Rainwater
Generally, the quality of rainwater is very good. Rainwater helps wash accumulated salts, magnesium and calcium carbonate from soil.
It helps reduce water costs and energy costs.
Harvesting rainwater reduces flooding and erosion by holding rainwater on site. If large amounts of rainwater are held in a pervious area, it can percolate into the water table.
What is water harvesting?
Water harvesting is the capture, diversion and storage of rainwater. Harvested rainwater has a variety of uses.
Even where rainfall is scarce, harvesting rainwater can be dramatic.
For instance, rainfall in Santa Fe, New Mexico averages around 13 inches a year. That much water harvested from a 2,000 square foot surface (a roof, perhaps) can amount to over 15,000 gallons a year. That’s over 42 gallons a day. It might not seem much to areas with high annual precipitation, but in the desert, it’s considered bountiful.
But where do you put that much water?
You can store it, or you can use it. Using it immediately is simple – build a raingarden, direct it into berms or swales along hillsides, or into small holding ponds.
However, understand that in most desert areas, low humidity will cause high evaporation rates and water stored in open areas will dissipate quickly.
There are simple storage systems. Rainbarrels, either manufactured for that purpose or recycled receptacles (large plastic food containers are excellent because they have never contained toxic materials). Water from gutters or canales is directed into the containers. Hoses or drip irrigation tubes attached near the bottom take advantage of gravity to carry the water directly to plants.
Larger tanks are also available.
Gutters can be connected to each other in a way that allows water from the entire roof surface to be directed into a single holding tank.
Pumps, mechanical and electric flow valves, sensors and a number of other additions can be added.
Additonally, there are many energy-saving devices, like solar-powered rainwater sensors which guage rainfall and automatically adjust your irrigation systems, solar-powered valves and a whole plethora of other choices.
