Wednesday, Dec. 17, 2008 | Last year, almost 1 percent of the city of San Diego’s drinking water supply — 635 million gallons — got sprayed on freeway shoulders to keep plants green.
The water was pumped hundreds of miles from Northern California and the Colorado River, pushed through a vast system of pumps and aqueducts and treated to be safe for human consumption. Then CalTrans bought it from the city for $2.2 million and sprinkled it on medians and shoulders to accomplish what, in this semi-arid region, Mother Nature couldn’t.
CalTrans says it uses the water to irrigate plants that beautify highways, block views into private homes, create buffers in medians, control erosion and provide fire protection. Many of the plants are drought-tolerant, requiring less water than others, but they would not survive without irrigation.
The transportation agency doesn’t use the water it buys as efficiently as it could. The agency doesn’t have smart irrigation controls on 75 percent of its roadside sprinklers. Those would allow one person to turn sprinklers on or off with the touch of a button on a central computer.