JUST ADD WATER!
Water is the basis of all life. Out here in the desert, plants and animals have adapted to living in this arid environment. I am adapting as well. There is plenty of water out here as long as it rains occasionally. Conservation is the key.
Rainwater catchment is the ultimate reuse of a valuable resource. There is a saying out west that you can drill 1000 feet down for water or catch it from 10 feet above. Just one inch of rain on one square foot of roof surface renders over half a gallon of water. I have 256 sq. ft. of roof surface on my little building. That translates into one inch of rain equaling about 140 gallons of water. I currently have a 550 gallon storage tank attached to my gutter system. When the greenhouse building is finished, I will be adding and additional 1800 sq. ft. of catchment area and two 1550 gallon storage tanks.
In the meantime, I am building a small dam to catch some runoff that occurs through a draw near my building complex. I have noticed that even with just a half in of rainfall, 1000's of gallons of water surge through this area. Ultimately I will add a 3000 gallon tank to store water pumped from there for irrigation of the greenhouse.
My catchment system consists of a screened gutter, a first flush route that captures 3 gallons of the first dirty roof rain, then a 550 tank to store water, and an overflow to release water away from the building when the tank is full. When the tank is finally plumbed into the building, I wall add a sediment and carbon filter to keep it potable. Light does not get into the tank which keeps bacteria from growing in there. The storage tank is black plastic and you might just think that water stored in there sitting in the hot sun must get awfully hot - but it doesn't. The evaporative cycle that occurs inside the tank helps keep the water cool, plus it takes an awful amount of heat to raise the temperature of 550 gallons of cool rainwater.
go to the "stuff" page for more information about rainwater harvesting.