Inland water agencies are serious about capturing storm runoff
Janet Zimmerman
Press-Enterprise
02/08/2010
Long before Southern California's water supplies dwindled, storm runoff was something to be disposed of quickly by sending it down concrete channels to the ocean.
But no more, say water officials who are coping with shortages caused by drought, population growth and environmental restrictions on imports. They want to capture every drop, especially during intense storms like those in January that dumped more than 3 inches of rain in many Inland areas.
"Our 20th century thinking was, 'Storm water bad, flood water even worse.' We're now saying that's water we desperately need," said Celeste Cantu, general manager of the Santa Ana Watershed Project Authority, which plans and builds facilities to protect the water quality of the drainage basin that starts in the San Bernardino Mountains.
Capturing 100 percent of the runoff from all but the most torrential storms would increase the local supply by about 25 percent, said Richard Atwater, general manager of the Inland Empire Utilities Agency in Chino.
That would be enough to save up to $200 million on imported water over the next decade in Riverside and San Bernardino counties, he said, and the savings would be passed along to customers on their water bills.
Efforts to harvest runoff are growing.
Water agencies are expanding their use of holding ponds that allow water to percolate into the ground and recharge aquifers for later use. And more cities and counties are mandating green building construction that catches excess water in on-site cisterns or rain barrels and uses less paving, a large contributor to runoff.
One of the most significant projects includes improvements on the Santa Ana River, south of the Seven Oaks Dam near Highland, that allow the capture of trillions of gallons of water once lost to Orange County.
In the Chino groundwater basin, which includes parts of Riverside and San Bernardino counties, about $50 million has been spent in the past decade to expand spreading grounds that allow runoff to seep into the soil, Atwater said. The district captures enough rain to supply about 6,000 families for a year.
Such projects represent progress, but officials say much more needs to be done, both regionally and at the individual level with improvements such as barrels to catch rain at homes.
"We don't do a very good job with conservation, recycling or storm water management, all supplies that can be used for irrigation, dust control, fire suppression and can be treated and injected back into aquifers. We have a long way to go," said Wendy Martin, state Department of Water Resources drought coordinator.
"We as a society need to demand that our water be treated with respect, and captured and used and used and used," she said.
Need Drives Change
At the Frontier Project in Rancho Cucamonga, parking lots and walkways are made of permeable materials so that water percolates into the ground. Excess surface water is naturally cleansed in slender ditches, called swales, which direct runoff to an underground cistern for irrigating the landscape.
The building, part of a movement known as low-impact development, was finished late last year by the Cucamonga Valley Water District.
The headquarters of the Inland Empire Utilities Agency has similar features, including porous concrete and a 20-acre wetlands park fed by storm water.
"Partly why all this is changing, we're not getting more from the Colorado River, there's gridlock in the (Sacramento-San Joaquin) Delta and imported water is too expensive," Atwater said.
"Fifty years ago when the area was growing rapidly, if we had had rain barrels and designed new homes so the water stayed on site, we'd be a lot better off," he said.
The Riverside County Flood Control and Water Conservation District is also thinking capture.
In Temescal Canyon between Lake Elsinore and Corona, the district wants to purchase land in the floodplain to prevent development and protect the natural percolation and water quality there, said Steve Thomas, assistant chief engineer.
In recent years, his agency and others also have begun to rethink the concrete-lined channels that whisk water away from cities.
Earthen bottoms allow water to sink back into the ground and now are used when possible, he said. But retrofitting most channels isn't an option because housing is built right to the edge, leaving no safety margin for overflow.
Catching Water
The Santa Ana River carries snowmelt from the San Bernardino Mountains and storm runoff through nearly 100 miles of urban areas.
Improvements recently were finished on the Cuttle Weir, a small, dam-like structure a half-mile from Seven Oaks Dam that will double the amount of river water that can be diverted. The work allows local districts to catch an additional 300 acre-feet of water per day during peak runoff. One acre-foot of water can supply two average households for a year.
The water will be used to recharge the Bunker Hill Basin, which supplies San Bernardino Valley and the city of Riverside.
Under an agreement with the state, Orange County is entitled to 42,000 acre-feet of Santa Ana River water per year but had been receiving more like 190,000 acre-feet annually because the water wasn't being captured upstream, said John Rossi, general manager at Western Municipal Water District in Riverside.
