SOUTHERN CALIFORNIA’S ENVIRONMENT At the Crossroads : Ground Water: <i> THE PERILS TO ITS PURITY</i> : Dairies Churn Out More Than Milk

They rise, like dwarfish versions of the ancient Egyptian pyramids, from the lush, green floor of the Chino valley--mounds of cow manure up to 40 feet high. Smelly blemishes on an otherwise scenic landscape, they represent more than just an aesthetic nuisance. They symbolize what some experts call one of the the most critical water quality problems facing Southern California: pollution of the Chino ground water basin.

More than 512,000 tons of manure is produced annually in the Chino Agricultural Preserve, a gently sloping flood plain between the Riverside and Pomona freeways. With 340 farms housing nearly 300,000 cows, the 17,000-acre preserve is host to the highest concentration of dairies in the world.

Though the bucolic valley provides a soothing contrast to the sprawl overtaking the rest of the region, the perpetual stream of dairy waste it produces is fouling the underground lake that supplies drinking water for most of western Riverside and San Bernardino counties. As the manure decomposes, it releases harmful nitrates, which ultimately seep into the subterranean sink below.

Runoff from corrals carries still more contamination into the water supply, much of it traveling through surface gullies that empty into the Santa Ana River--Orange County’s main water source.

Health officials are alarmed because high concentrations of nitrates can cause “blue baby syndrome,” a potentially deadly ailment that deprives infants of oxygen. Already, 20% of the basin’s wells have been limited to agricultural use only, and water pumped from many others must be blended with clean water before it is suitable for consumption.

Dairymen are as anxious as anyone about the contamination, but many complain their contribution has been exaggerated. State water officials acknowledge that fertilizers used for decades on the region’s vineyards and citrus groves account for part of the nitrate pollution. But they say poor dairy management practices are to blame as well.

Consequently, ranchers now must meet stiff standards governing allowable runoff and the volume of waste stored on their property. But complying has been difficult. As subdivisions have sprouted on former farmland, the market for manure has withered, forcing dairies to pay upwards of $20 per cow per year to have it trucked away.

“Used to be, people would pay good money for this stuff, but nobody wants manure any more,” lamented Erwin Stueve, 65, herdsman at the giant Alta Dena Dairy, where 17,000 cows produce 65,000 gallons of milk--and 700 tons of manure--each day.

While sympathetic, state water quality officials are not hesitant to take action. Last year, 10 dairies were slapped with fines ranging from $2,000 to $40,000, while many more were warned to mend their ways.