Urgent pleas for extra water conservation have gone out to nearly one million Southland residents in recent days as the region's largest water wholesaler reacts to a second unanticipated problem in coping with the drought.
The problems cropped up in connection with changes made by the Metropolitan Water District (MWD) to "rebalance" its system for transporting, treating and delivering water imported via the California Aqueduct and another aqueduct from the Colorado River.
The temporary shutdown of the Mills Water Treatment Plant in Riverside Friday afternoon came with only a day's notice to the water districts it supplies, and just 50 hours after the MWD's largest treatment plant, Jensen in Granada Hills, was taken offline.
For now, the MWD is operating with only three of its five treatment plants. The goal is to finish the needed work so Mills and Jensen can come back online by the end of the weekend.
The Mills plant has long been the primary source for areas of Riverside County with 330,000 people. For decades, Jensen has been virtually the only source for more than 650,000 in the west end of Los Angeles County and most of Ventura County.
The affected areas have water reserves, but limited capacity to do the needed treatment before delivery, prompting the pleas to consumers to cut back as much as possible until the two plants come back online.
"We're asking them to turn off their sprinklers. We're also asking them to put off washing clothes, washing cars, any non-essential water use," said Paul Jones, general manager of the Eastern Municipal Water District, which has relied on Mills water to meet the needs of Moreno Valley and Perris.
Both Eastern and its neighboring Western Municipal Water District planned to use reverse 9-1-1 calling systems to notify customers to begin cutting back immediately. With cooperation, water officials expressed confidence they can get through the weekend.
But they are counting on the plants to come back online as scheduled.
"Two days we feel comfortable about. We just don't want to wait, we don't want to take chances," said John Rossi, General Manager of Western Municipal.
"I'm sure a couple of days won't hurt as long as the weather's not too bad," said Mission Grove resident Bridey Abad.
"I won't wash the car," promised Jeff Clayton of Moreno Valley.
Until now, in stark contrast to much of California north of the Tehachapi Mountains, the storage reserves built up by the MWD have enabled it to shield the six southern counties it serves from the impact of the drought.
Both Jensen and Mills are configured to draw water from the California Aqueduct. But the drought has forced dramatic curtailments in deliveries, allocations for 2014 now set at only 5 percent of normal, though agencies such as the MWD that have banked water in previous years are able to draw on their storage.
"We're making historic, extraordinary changes to our system," said Jim Green, MWD's manager of water system operations.
On the western side of the MWD's service area, the drought had created a growing squeeze. Both the Las Virgenes and Calleguas Districts rely almost entirely on water from Jensen, but the limited supply from the California Aqueduct had reduced Jensen's output to less than a fourth of its capacity, Green said.
Ordinarily, the MWD does not pump Colorado River water as far west as Ventura County. But with Colorado River supplies close to average this year, that was seen as the best option to keep that area from running low on water.
But when the pumping began, strains on the system became apparent, and there were even concerns that a portion of it could "seize up," said Eric Bergh, resources manager for the Calleguas district.
As a fix, MWD engineers designed a metal plate with holes like swiss cheese--an "isolation gate"--to be installed at Jensen. That would require temporarily shutting down not only the Jensen plant, but also the Burbank pumping station that had begun sending Colorado River Water to Calleguas and Las Virgenes.
The MWD decided it had to be done, and soon, and the shutdown came just two days later on Wednesday night.
Meantime problems were developing on the California Aqueduct's eastern branch, which has long supplied the water treated for delivery by the Mills Plant. Earlier this year, because of the drought,
Mills was cut off from aqueduct deliveries, according to Debra Man, the WMD's Chief Operating Officer. So that Mills could continue to operate, MWD drew on on water stored in a local reservoir.
In recent weeks, MWD got approval from California's Department of Water Resources to reopen the pipeline that connects Mills to the aqueduct, in order to take water stored several hundred miles to the north in San Luis Reservoir. But when water surged back into the high pressure pipeline, a pressure relief valve failed, Man explained.
The valve is located in Colton, more than 10 miles from the Mills plant. But the valve could not be fixed without shutting down the pipeline, cutting off the supply to Mills.
Deliveries will resume when the valve is fixed. MWD has been assured this repair, like the installation of the isolation gate at Jensen, will be completed over the weekend, Man said.
The MWD's Chief Operating Officer and assistant GM harbors no illusions that this is the end of the rebalancing or "juggling," as she called it.
"I think we're going to find that we're going to have to adjust facilites. We may have to make some modifications and improvements," she said.
And the potential for more unanticipated problems that need emergency fixes?
"I think we'll find that may be the case." Man said.