Editor’s note: This is the third in an occasional series on rivers, lakes, reservoirs, the Delta, and the weather that play key roles in supplying Manteca, Ripon, Lathrop, and much of the rest of California with water.
Rain and snow are currently running ahead of average on the Stanislaus River watershed.
No one that manages water that depends on the run-off and Sierra snow melt is getting giddy in hopes that water shortages will soon be a non-issue. Besides the declaration of hydrologists that California needs above average rainfall and snowpack through at least 2019 to get reservoirs back to normal levels to break the severe drought that has lingered for four years, there is a move afoot in Sacramento to increase unimpaired water flows on the Stanislaus River from the current 30 percent between January and June to between 40 and 50 percent.
The State Water Resources Control Board also wants to do the same to the Tuolumne and Merced rivers. No other rivers in the state are being targeted for what would be as much as a 66 percent increase in water committed to fish.
New Melones Reservoir on Sunday was at 365,519 acre feet or roughly 15 percent of the 2.4 million acre feet of water it is designed to hold.
The historic average inflow to New Melones is 1.05 million acre feet of water. Since 1985, the average inflow has dropped to 996,000 acre feet. In 2015, the average flow dropped down to around 250,000 acre feet.
Currently, if the historic average flows into New Melones, the 1.05 million acre feet is committed to the point there wouldn’t be a drop left over to assign to storage.
The water split currently is 600,000 acre feet reserved for the South San Joaquin Irrigation District and Oakdale Irrigation District, 247,000 acre feet for fish in the Stanislaus River, 148,000 acre feet for water quality, 66,000 acre feet that is lost to evaporation, and 45,000 acre feet to the Stockton East Water District.
Should the state next month make their bid to increase unimpaired flows of 50 percent for January to June, some experts are predicting it would require taking as much as 80,000 acre feet from only three available sources — OID, SSJID, and Stockton East.
And since OID and SSJID have senior adjudicated water rights, Stockton East could end up with no water even in a normal year while full water deliveries to OID and SSJID would be imperiled.