4. Lawn Sprinklers: Fountains of Backyard Verdure or Pernicious Aquifer Guzzlers?
The water sprinklers that keep the turf lush and the flowers blooming can consume 265 gallons (1,000 liters) an hour, says Waterwise, a U.K. water-conservation group. This amount rivals or exceeds estimates of what an average U.S. household uses daily. A good tip: deploy the sprinkler either in the early morning hours or at dusk; less water will evaporate in the cooler temperatures and more will actually get to the plant roots. But be mindful about leaving it on; besides potentially drowning your petunias, you may also be breaking the law. A new drought-busting measure in the City of Los Angeles will permit automated sprinklers to run only 15 minutes a day this summer.
5. Well-Watered Desert Resorts
The term "desert resort" is synonymous with the City of Las Vegas. The Venetian canals of the Bellagio, as well as the Mirage's water-and-fire volcano, make conspicuous water consumption in Sin City iconic. Appearances can be deceiving, though. In fact, the Las Vegas Strip accounts for just three percent of local water use, according to the Southern Nevada Water Authority. Fully 70 percent of the city's water supply goes toward irrigating the 60-plus golf courses and the many residential lawns in the area. The municipal government has, however, taken steps to scale back on the city's greenery, for example, by cutting the maximum size of a domestic lawn to just a backyard patch. Nevertheless, keeping grass verdant in the middle of the desert is arguably folly in the first place.
6. Biofuels' Hidden Downside
Biofuels typically burn cleaner than fossil fuels and therefore emit less carbon dioxide into the air. But plant-power sucks up ridiculously large quantities of water compared with oil and natural gas production. A study (pdf) presented at an American Society of Mechanical Engineers conference in 2007 offers some alarming estimates: Producing a gallon (3.79 liters) of corn ethanol, for example, consumes 170 gallons (644 liters) of water in total, from irrigation to final processing. Soybean biodiesel manufacture needs some 900 gallons of water (3,400 liters) per gallon of fuel. On the other hand, the water requirement to make a gallon of regular gasoline is just five gallons (19 liters).
7. Agriculture in the Arid Southwest
Much of the U.S. Southwest is a desert—at least it was at one time in the past. But about 90 percent of the Colorado River's water is today diverted into these parched lands for agricultural irrigation. Perhaps half of this regional resource does not even reach the intended crops because it is lost to evaporation and seepage during pumping and transport, according to a 1997 Cornell University study that appeared in the journal BioScience. Many farmers rely on flood irrigation, which, though inexpensive, is a highly inefficient means of delivering water to thirsty plants. The Colorado's dwindling water flow threatens the supplies of seven states and has spawned a plethora of lawsuits regarding water rights. As our featured article on water points out, shaving irrigation water by 10 percent would save more than is used by all other water consumers put together. A prime example of this ill-advised approach is growing alfalfa in the desert.