It’s official.
All of San Joaquin County and the entire Stanislaus River watershed that supplies water to South County farmers as well as Manteca, Lathrop, and Tracy are in the grips of an exceptional drought.
The National Weather Service’s drought monitoring effort has expanded the highest drought designation to cover 58 percent of California. The Eastern Sierra, San Diego, Inland Empire east of Los Angeles, and north and east of Mt. Shasta are considered to be in extreme drought. The Mojave Desert and a small chunk of extreme northwest California on the Oregon border have severe drought conditions.
Before last week the Lodi area and eastern San Joaquin County was only in an extreme drought condition while everywhere else including Manteca, Lathrop, and Ripon was at the fifth and final level for droughts as established by the federal government.
South San Joaquin Irrigation District was informed Wednesday by the Bureau of Reclamation that the projected storage for New Melones Reservoir at the end of the weather year on Sept, 30 is expected to range between 319,000 and 339,000 acre feet. The reservoir’s capacity is 2.4 million acre feet. New Melones is the state’s fourth largest reservoir. Others with larger capacities are Shasta Lake at 4.5 million acre feet, Lake Oroville with 3.5 million acre feet and Trinity Lake with 48,000 acre feet more than New Melones. Lake Tahoe, by comparison, is 732,000 acre feet.
“What happens in October and November will be interesting if it doesn’t rain because the Bureau is required to spill about 33,000 acre feet in October as a fall attraction flow for fall run Chinook Salmon and then another 8,000 acre feet in November,” noted SSJID General Manager Jeff Shields.
Today starts the SSJID’s mandatory water cutbacks for Manteca, Lathrop, and Tracy. The three cities will be allowed to take only 20 percent of what they used in August and September of last year over the next two months.
Since Manteca’s use of surface water from the SSJID was actually up 1 percent last month while overall use dropped in June by 20.4 percent from June of 2013. Manteca has switched to more pumping at its 15 municipal wells to reduce surface water use.
The city is making sure they don’t go over as the SSJID will shut off valves for water delivery to the city. The surface water is critical to mix with several wells in north Manteca that will have arsenic levels that surpass federal limits if the well water isn’t blended with treated surface water to dilute the arsenic levels.
The SSJID had asked for the cities to voluntarily reduce their draw from the surface water treatment plant by 20 percent back in February. Lathrop has reduced their water draw by 16 percent and Tracy by 14 percent. Lathrop will also start pumping more well water.
That reduction coupled with the early end of the irrigation season and the mandatory cutback to the cities will leave the district short 1,616 acre feet of the 225,000 acre feet they are being allowed by the Bureau to draw this year from New Melones. They will make that up by lowering Woodward Reservoir earlier this year and hold the lake level at 204 feet as opposed to the normal 210 feet.
The district is also trying to cover the gap by intensifying efforts to avoid spills from individual grower operations. The SSJID is looking to optimize the use of its own wells to the greatest extent possible. The SSJID will also ask growers that have wells to rely on those for their last irrigation after harvest.
District irrigation runs for farmland are ending before Sept. 30. That’s at least 10 days earlier than normal.
