South San Joaquin Irrigation District is caught in a Catch-22 that could make water conservation the highest priority in the coming months for farmers as well as the cities of Manteca, Lathrop, and Tracy.
The bottom line: Given current conditions the SSJID could end up with just enough water to get through 2018 providing they don’t start the first irrigation run until March 5.
Due to the record high temperatures, almond trees starting to bud and soil moisture issues some farmers are expected to push for an early start to the irrigation season. The final decision lies with the SSJID board when they meet Tuesday at 9 a.m. at the district office, 11001 East Highway 120.
There are a number of issues in place running the gamut from needed repairs being wrapped up at Woodward Reservoir, how the Bureau of Reclamation manages water at New Melones, a significant “rain and snow doughnut” that’s developed in mid-winter, and the current snowpack on the Stanislaus River watershed.
As things stand now, the SSJID may have up to 240,570 acre feet of water entitlement available for use during the 2018 irrigation season. At first glance that appears to be good news given the SSJID used 200,000 acre feet in 2017. Last year, however, had a very wet spring that significantly lowered irrigation demands during March, April and May. In May of 2013, a relatively dry year, SSJID used 239,700 acre feet or essentially what is projected to be available this year.
Bureau cutting back
flood control releases
in response to dry pattern
The Bureau has dialed back releases from New Melones that will avoid the district’s storage account at the reservoir being depleted by April 2018 as originally projected. Thanks to the Bureau’s actions, it now appears there will be have 103,000 acre feet in that storage account that is shared with the Oakdale Irrigation District.
Based on Tri-Dam Project snow survey data from Feb. 5, the SSJID’s share of the runoff this year is expected to yield 189, 070 acre feet of water which is also how much OID would receive.
The water conservation account at New Melones was created as part of the 1988 agreement that allowed the Bureau to build New Melones by inundating the original Melones Reservoir that SSJID and OID built in 1925. The two districts are entitled to the first 600,000 acre feet of runoff each year based on legally adjudicated senior water rights that is collected at Donnells and Beardsley. They can have only up to 200,000 acre feet set aside in carryover in the conservation account at New Melones.
The agreement has a provision that bars the two districts from taking in excess of 225,000 acre feet apiece whether it is current year run-off or from the conservation account in years where the Bureau assess shortages to contractual supplies to Central Valley Project users from the Stanislaus River. The CVP is highly likely to not provide full deliveries given earlier this week the State Water Project that also relies on the Sierra snowpack advised contract customers that current conditions point to only a 20 percent water delivery this year.
SSJID and OID’s
Working against SSJID and OID as well — as bizarre as it may seem — is last year’s record snowpack.
The Bureau has been operating New Melones under flood control guidelines to clear up space for the spring runoff before Mother Nature clearly slipped into dry mode. The flood control operations in terms of pumped up releases are needed to keep New Melones from being in a position Don Pedro on the Tuolumne River was last year with water spilling or creating a situation where the dam’s integrity could be challenged as it was at Oroville Dam.
In 1997, the Bureau was criticized for operating New Melones as if it were a dry year. When unusual warm December rains in the Sierra caused much of the snowpack to melt, the Bureau scrambled to increase releases to protect the integrity of the dam. The end result was a surge of water down the Stanislaus and ultimately the San Joaquin River that led to levee failures in nine places triggering the flooding of 70 square miles southwest of Manteca, south of the river in Lathrop, and east of Tracy.
New Melones ended the water year on Sept. 30 with 2,023,891 acre feet in storage. The Army Corps requires New Melones to achieve a maximum storage of 1,9700,00 acre feet by Nov. 1. Since it was at 2,000,464 acre feet on Nov. 1, the Bureau was required to increase releases. When that is done, language in the agreement requires water released to come from the conservation account first. The account had 200,000 acre feet in it as of Nov. 1. Most of the pumped up releases from New Melones since Nov. 1 has been drawing down the conservation account that was robust enough in September for the 2018 water outlook to be strong. That was before Mother Nature decided to turn off the spigot.
The Bureau has since responded to the dry hydrology and is tapering off releases meaning instead of no water carry cover the SSJID as its share will have 51,500 acre feet.
Rain at 41% or normal,
snowpack at 29 percent
A ridge of resilient high pressure in the Pacific Ocean similar to what caused the 2012 to 2006 drought has rainfall at only 41 percent of average as of Feb.5 while snowpack water content is even lower at 29 percent.
Currently measurable rain and snow aren’t expected in the Northern San Joaquin Valley or Central Sierra until March 10.
The district is also wrapping up work on intakes at Woodward Reservoir for the water treatment plant that serves the cities of Manteca, Tracy, and Lathrop. That work was delayed because of the bridge replacement work on McHenry Avenue south of Escalon across the Stanislaus River involving culverts impacting the SSJID’s main canal made it impossible for the district to drop the level of Woodward to do the intake work earlier.