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On Rainwater Harvesting

by / 0 Comments / 71 View / August 1, 2016

By Michael Brown

The hot “dog days of summer” are upon us, and both we and our plants are feeling the effects. So far, there’s only been a few 100-plus-degree days. Compared to the past few years. I guess we’re lucky.
We’re watering the lawn twice each week, on Monday and Friday nights. The lakes are full, but I still feel guilty. I figure, at about 50 gallons for every 100 square feet, we’re using about 3,000 gallons per week. According to the utility bill, that amount of water costs about $12. Fortunately, a lawn doesn’t require irrigation all 52 weeks of a year. Even so, it’s a moderate expense, and, given that we have thousands of homes with lawns in Central Texas, more than a significant amount of water is taken from our reservoirs to water lawns.
Besides lawns, many homeowners require copious amounts of water for their houseplants and gardens. Some users have made the smart move to harvesting rainwater. Last May, I attended a rainwater-harvesting clinic conducted by the Bell County Master Gardeners at their building on Main Street, which is next to the Texas A&M AgriLife Extension Service office. The first part of the clinic focused on general information and the second part consisted of actually constructing a rain collection system for each participant to take home.
Todd Strait, of the Clearwater Underground Water Conservation District, spent about an hour discussing various topics, from rainfall statistics to the legal aspects of capturing water. Many homes have roofs with gutters, and those gutters provide the easiest way to collect water. With a good 1-inch downpour of rain, a gutter can collect 0.6 gallon per square foot of roof area (600 gallons per 1000 square feet). Here in Central Texas, our average annual rainfall is 33 inches, so that’s almost 20 gallons per square foot of roof area. Even a small roof provides a good bit of water.
Although many communities out West have ruled that rainwater belongs to the existing water-rights owners, that is not so here in Texas. Strait explained that our state not only permits rainwater capture, it promotes the practice, and even provides a sales tax exemption for purchasing the necessary equipment. All state agencies are encouraged to harvest water when possible.
Unsurprisingly, there is quite a bit of science to collecting rainwater efficiently and using it effectively. Karen Colwick of the Master Gardeners spent another hour or so showing examples of different collection systems and explaining the best ways to set up barrels and hoses. Since water pressure increases with height, it turns out a barrel would have to be above a roof to provide enough pressure to distribute its water with drip irrigation. At ground level, water can be drained from a barrel into a bucket, but slowly. Most folks probably won’t be able to water their lawns without a large investment in pumps and storage tanks, but buckets work fine for potted plants and gardens. And, according to the Master Gardeners, rainwater is far superior for plants than city water from the tap.
By the end of the clinic, I had made ready four rainwater collection barrels, and I intend to put them to good use. The next rainwater harvesting clinic is tentatively scheduled for September. Call the Extension office at 254.933.5305 for details and to get your name on the list of participants.
Walter Stegner, in his book Beyond the Hundredth Meridian, writes of the trials of John Wesley Powell, the great American explorer, who tried and failed to get the federal government to control the westward expansion of the U.S. during the late nineteenth century. Powell foresaw the water shortages that have now come to pass. With thousands more people coming to our state each month, it just makes sense to do all we can to conserve and maintain our water supplies. A quote from Ben Franklin is quite appropriate: “When the well is dry we know the value of water.”