Shades of Green: Harvesting rainwater

Green meter: medium green

Harvesting rainwater is an easy way to green up your lifestyle. Rain barrels can be purchased at local gardening centers or are made at home with a recycled food-grade barrel and a few parts from a home improvement center. Recycled food grade barrels vary in price from $15 to $30 dollars and the parts to manufacturer your own rain barrel cost approximately $25.

However, for me, a rain barrel was a mere drop in the bucket for the amount of water I use on my small, urban food-producing garden. The large 300-gallon green tank shown in the photo above is my rainwater-harvesting machine. With a small transfer pump, I am able to run a sprinkler to water my garden. For the serious gardener, or someone interested in maintaining a small lawn, a large water holding tank will prove more useful than a 50-60 gallon rain barrel.

One square foot of roof surface yields 0.62 gallons of water with one inch of rain. The average two car garage has a surface area of approximately 600 square feet; one half inch of rain would yield just under 200 gallons of wasted rain water run off from only the roof over your garage! Using another example, half of the roof area of a 1500 square foot ranch is approximately 850 square feet; collecting the rainwater using gutters to guide the water to a central point would yield over 250 gallons in a half-inch rain and over 125 gallons with a mere quarter of an inch of rain.  Check out this handy calculator to figure out your roof runoff.

Your harvested rainwater can be used for general watering or used to maintain the level of a pool. You can also use clean rainwater to run a child’s sprinkler for fun or fill up a small wading pool. Your rain barrel or tank should have a mechanism (such as screening) for keeping debris and pollen out of your tank if you plan to use it for swimming or playing.  Your collected rain water can also be used to wash your car with a small transfer pump.

Collecting rainwater provides more than a means to water your garden and yard; collecting rainwater decreases the run-off from your house and lot. Run-off contains nutrients and chemicals from your lawn and garden; this excess of nutrients and chemicals then run into our watershed and, depending on your location, directly into your drinking water. Nutrients such as nitrogen, both naturally occurring and added by way of fertilizer, run into our rivers and streams contributing to the decrease of oxygen content. In worst-case scenarios, this can cause fish kills and can increase the algae populations to unnatural levels. Chemicals and nutrients dumped into drinking water reservoirs create additional complexities for our local municipalities with regards to filtration and processing.

For more in-depth information, please visit the Texas Water Development Board website