Domestic water deliveries to Manteca, Lathrop, and Tracy could be curtailed sharply as the South San Joaquin Irrigation District prepares for what is shaping up to be the worst year for water availability in history.
Based on current conditions, the SSJID is projecting they will have only 34 percent of a normal supply available for delivery through March 1, 2013.
The SSJID board will discuss various options including curtailing deliveries to the three cities and a host of proposals impacting farm irrigation when they meet Tuesday at 9 a.m. at the district office, 11011 E. Highway 120.
It is a drastic turn of events from the three-year drought that ended in 2010 when SSJID was selling water they had conserved to other districts where supplies were so short farmers were literally ripping out orchards and letting land go fallow.
The big difference is the severity of the lack of snowfall this winter. During the drought, snowfall was below normal each year but did not drop below 60 percent overall. With just three weeks left of traditionally the heaviest snow period in the Sierra, the snowpack is just at 37 percent of normal for this date. The central Sierra that supplies the Stanislaus River basin that SSJID relies on is in even worse shape. If conditions don’t change and there isn’t unseasonably warm temperatures that could accelerate the snow melt, the snowpack based on today’s readings translate into less than 30 percent of normal statewide on April 1. That date is the most critical for determining water delivers up and down the state.
The Sierra snowpack is essentially the most critical and largest reservoir of water in California as it accounts for a third of the state’s water supply.
Manteca Public Works Mark Houghton has indicated the city is starting to work on strategies to step up water conservation efforts. The city relies on a dual system of well water and surface water from SSJID.
Simply stepping up the pumping of water from underground sources isn’t necessarily a solution.
Manteca needs a certain flow level of surface water to blend with water at several wells to reduce arsenic levels below federal standards. Increased pumping would mean increased power costs that in turn could lead to higher power bills. There is also the question of underground aquifers in California already being stressed. And while Manteca’s wells in the past haven’t had to deal with salt water intrusion it is always a problem during major dry spells. A number of domestic and farm wells as far east as Jack Tone Road had significant salt water intrusion during the drought in the mid-1970s.
Lathrop uses a combination of wells and surface water as well. But unlike Manteca that runs its wells only during the big demand months in the spring, summer and early fall Lathrop runs its wells year round. They have had salt water intrusion issues with their domestic wells as does the City of Tracy.
Options the SSJID board will consider to conserve water within the irrigation system include:
•pushing back the date for the initial irrigation delivery run.
•implementing flood irrigation limits.
•implementing a variable rotation schedule for irrigation deliveries.
•implementing drip/sprinkler irrigation quantity limits.
•implementing alternate supplies such as the district leasing private pumps, using district wells, and drilling additional wells.
•allowing for inter-parcel transfers/fallowing.
•setting a new maximum level for Woodward Reservoir.
•enforcing Tier 2 service agreement provisions.
