There's a new range war on California's grazing lands and the enemy is water pollution. For many years the nation's fight against water pollution focused on specific sources, such as factories. But in recent years, attention has turned to so-called "nonpoint" sources of surface and ground-water pollution. "Such problems include run-off from construction sites, urban areas, forest lands and agricultural lands -- including livestock grazing lands," says John Harper, a UC livestock and natural resources advisor in Mendocino County. To protect the ecological health of these lands, which filter most of the state's surface water, Harper and UC Davis range agronomist and pasture specialist Mel George are helping livestock producers develop specific water-quality plans for their ranches.