Water Replenishment District of Southern California expands groundwater de-salter facility amid concern of possible drought

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Courtesy United States Drought Monitor
The United States Drought Monitor, a weekly mapping project conducted by various government agencies, released a map on Feb. 8, which indicates that California is experiencing early signs of drought conditions. The data shows that southern California is undergoing symptoms of severe drought. The Water Replenishment District of Southern California expanded the amount of groundwater it could recycle for consumption as a method to prepare for drought and water conservation efforts.

The United States Drought Monitor (USDM), a project of government agencies and other partners, recently released a heat map of California, which indicates that some regions of the state are already experiencing early drought conditions as the winter season comes to a close.

In an effort to conserve water, the Water Replenishment District (WRD) of Southern California expanded the capacity of brackish groundwater it can recycle from the Robert W. Goldsworthy Groundwater Desalter facility based in Torrance. The $18-million expansion of the plant allows for double the amount of groundwater to be cleaned and delivered for daily use by Torrance’s 105,000 residential and business customers.

The expansion of the plant comes just days after the USDM indicated that Southern California is experiencing severe drought conditions.

The WRD began operating the Goldsworthy facility in 2002 as a pilot project to clean up billions of gallons of brackish groundwater that remained from past seawater contamination of groundwater-bearing aquifers that underlie the coastal areas of south Los Angeles County, according to a press release.

The Silverado aquifer, and other primary aquifers historically used for local water supply, were adversely affected by seawater intrusion that occurred many decades ago. As a result, about 650,000-acre-feet of groundwater— 1 acre foot equals 325,851 gallons— became brackish in the coastal aquifers managed by the WRD.

Brackish groundwater refers to water that has more salinity than fresh water, but not as much as seawater. According to WRD Board President John Allen, the process of recycling this kind of water for consumption is the key to a more sustainable future.

The technique used to clean the water is called reverse osmosis, which is when a solvent passes through a porous membrane opposite to that of natural osmosis. The solvent is subjected to a hydrostatic pressure greater than the osmotic pressure.

In this case, salty groundwater, the solvent, is blasted at high pressures through tightly packed screens. The screens act as the porous membrane, which captures the particulates in the water.

“After treatment, the Goldsworthy water will be of very high quality and exceed all federal and state water safety standards,” a press release from the WRD states.

The water being treated at the Goldsworthy plant is not as salty as seawater, but it is too salty to drink or use for irrigation.

“First of all, we are in another drought,” Allen told the Signal Tribune during a phone interview Tuesday afternoon. “We’ve had eight or nine very dry years each one worst than the other. What the WRD has decided to do is to become independent of northern California water and Colorado River water.”

He said the WRD wants to reduce the amount of imported water it buys from the Metropolitan Water District (Metropolitan), which currently equates to 21,000 acres feet of water. The WRD uses imported water from Metropolitan to keep its underground aquifers full.

Metropolitan is a regional wholesaler that delivers water to public agencies serving 19 million people living in the Los Angeles, Orange, Riverside, San Bernardino, San Diego and Ventura Counties. Metropolitan currently delivers an average of 1.7 billion gallons of water per day to a 5,200-square-mile service area, according to its website.

Bob Muir, a spokesperson for Metropolitan, said his agency supports the recycling process of brackish groundwater as it coincides with its ambitions to become independent of water from regions such as northern California and the Colorado River.

Metropolitan has a long-term water-resource plan called the Integrated Resource Plan (IRP), which is the agency’s water-supply blueprint for the next 25 to 30 years.

The IRP was created after a drought that occurred from 1987 to 1992. During that time, Southern California was highly dependent on imported water. In 1991, cutbacks of that northern water supply forced Metropolitan into “mandatory conservation.”

Since the adoption of the IRP, numerous updates to the plan were added throughout the years. Muir said Metropolitan has diversified where water resources come from all credit to the IRP.

“One of those pillars of water resources is water recycling,” he said. “We are part of the Goldsworthy groundwater desalting expanding project.”

Metropolitan has paid the WRD a total sum of $5 million for the desalting facility since the project’s beginnings in 2002. Muir said his agency offers economic incentives for water-recycling efforts.

He said the agency pays the WRD $340 per acre-foot of water that it recycles. By 2020, Metropolitan expects to have invested a total of $7.7 million into the Goldsworthy desalting facility.

“We are reaching our limits as far as how much water we can get from our two core supplies,” he said. “We know that Southern California is going to continue to grow and prosper, and it’s investments like the Goldsworthy expansion that is where we are going to get this water.”

As water-conservation agencies and water wholesalers look for ways to prepare for drought at the urban level, California farmers are also preparing their crops for drought conditions in the rural parts of the state.

Dave Kranz, a spokesperson for the California Farm Bureau Federation, told the Signal Tribune Tuesday during a phone interview that it has been a very warm winter in much of California, and that it does affect activity on the farm.

Farmers of certain produce expected those crops to get irrigated by rainfall water during the winter months. In some cases, farmers in the central valley have begun to irrigate their orchards and vineyards due to the lack of rain they typically have, according to Kranz.

“It’s a little early yet to know just exactly how it’s all going to play out because we still have another six or so weeks of our typical rainy season to go,” he said. “We do have a cushion from last year since we had so much rain and snow a year ago, and our above-ground reservoirs are all in pretty good shape. That gives everybody a little bit of a cushion, but definitely, we would like to see more snowpack in the Sierra [Nevada], more rainfall to help replenish groundwater aquifers and have a more typical wintertime pattern; there is still time.”