Golf courses in arid Southern Nevada are saving a billion gallons of water each year by replacing thirsty grass with water-efficient landscaping.

The Southern Nevada Water Authority calculates that since 2001, Las Vegas-area courses have converted 425 acres from grass to water-smart landscaped courses. Eleven courses in Southern Nevada now are undergoing landscape conversions.

The Water Authority credits golf courses for their water conservation measures. All 43 local courses have on-site weather stations linked to their irrigations systems by computers that enable each course to base their irrigation schedules on daily weather conditions. These systems monitor the moisture given off by grasses and plants, so water is applied only as needed.

Current drought restrictions subject local golf courses to water budgets, restricting them to 6.3 acre-feet of water per acre. An acre-foot equals about 326,000 gallons. The calculation includes lakes and ponds that exist within a golf course and those serving as golf course irrigation reservoirs.

Once measured, the irrigated acreage remains fixed, creating an incentive for golf courses to convert unneeded turf to other styles of water-efficient landscaping. Golf courses must pay financial penalties for any water used over budgeted amounts.

The Water Authority also cites community cooperation with drought restrictions and water-efficiency programs for the drop of 18 billion gallons in water consumption between 2002 and 2006, despite the fact that 330,000 new residents moved into the area and 40 million people visit each year.

Southern Nevada gets nearly 90 percent of its water from the Colorado River, which currently is facing the worst drought on record.