L.A. River Study May Give Water 2nd Chance : Drought: Officials will test effluent that has been filtered through the ground to see if it is clean enough to replenish aquifers.

“There it is--take it,” said William Mulholland, patriarch of the Los Angeles water system, on the day in 1913 that Owens Valley water first cascaded into city reservoirs, fueling Los Angeles’ spectacular growth.

On Wednesday, Mulholland’s successors in the Department of Water and Power waited in a brushy earthen basin near Griffith Park, where another source of water announced its arrival by gurgling from a pipe.

In the current era of limits, this was not water from the pristine snows of the eastern Sierra, but from thousands of sinks and toilets.

The arrival of the water marked the start of the DWP’s Headworks pilot project, aimed at testing whether reclaimed water from the city’s sewage treatment plants can be cleansed to near drinking-water quality by the natural filtering action of the soil. The $800,000, two-year study is meant to support efforts to use reclaimed water for up to 10% of the city’s supply--not just to irrigate fairways and parks, as in most water reclamation projects now, but to replenish aquifers that are tapped by city drinking-water wells.

By early Wednesday morning, DWP officials had inflated a black rubber dam across the bottom of the Los Angeles River’s concrete channel near the Ventura Freeway and Forest Lawn Drive. The dam partially blocked the flow of the river, at least 80% of which is discharge from the Tillman Water Reclamation Plant in the Sepulveda Basin.

Water pumped from the river took at least half an hour to flow through 1,000 feet of galvanized steel pipe and begin soaking weeds and wildflowers in the Headworks spreading grounds, a nearby series of dry, shallow basins.

About 750,000 gallons of water per day will be diverted from the river to the spreading basin and allowed to percolate into the ground. The underground water will slowly seep toward the river and in six months to a year reach an extraction well that will pump it out to return it to the river.

The water will undergo laboratory tests both when it is pulled from the river and again when it is returned. DWP officials hope the tests, which will measure the cleansing power of soil bacteria and subsurface sand and gravel, will show that reclaimed water filtered through soil becomes fit to drink or that it would be with minor additional treatment.

Department officials said that if the results are favorable, they may be able to divert large volumes of Tillman water that now flows to the ocean. The water could be spread in the Headworks basin to sink into the ground and replenish city wells near Griffith Park.

According to department engineers, Tillman effluent is clean enough that it has improved the water quality of the Los Angeles River, perhaps making it possible to put the now-idled Headworks grounds to use again.

Years ago, the department regularly diverted storm water from the river to the Headworks but had to stop because the runoff water was too dirty, said Stephen A. Ott, a waterworks engineer with the DWP.

“When it rains, the water that runs off our surface streets” is laced with “greases and oils and pesticides that people apply to their lawns,” Ott said. The Tillman water, which receives advanced treatment, is much cleaner, he said.

Favorable results also could improve the prospects of the proposed East Valley Water Reclamation Project, an ambitious plan to use reclaimed water to boost city water supplies by about 7%. The plan calls for piping up to 45 million gallons per day of Tillman effluent to spreading basins in Pacoima and Sun Valley by 1995. The water would seep southward, eventually reaching city wells in North Hollywood that provide more than 10% of the city’s water.

Under current state health guidelines, the DWP would be required to dilute the reclaimed water with at least four times as much storm or surface water, Ott said. He said the Headworks study may show that such large dilutions are unnecessary.

Using reclaimed water to boost ground water supplies is not a new idea. Since the 1960s the Los Angeles County Sanitation Districts have been using reclaimed water from two sewage treatment plants, diluted with large amounts of surface water, to replenish aquifers tapped by cities and water districts in southern Los Angeles County.

The DWP currently operates only one reclaimed water project, using 1,000 acre-feet per year to irrigate the Griffith Park golf courses and landscaping along the Golden State Freeway. Several other projects are under consideration.

Recharging Ground-water Supplies

Water is diverted from the L.A. River (80% of which is discharged from the Tillman Water Reclamation Plant in the Sepulveda Basin) to a pool (1) where it seeps into the soil and then, once underground (2), will slowly move in the direction of the river. In six months to a year it will reach an extraction well that will pump it out to return to the river.