MWD’s Delta Islands Water Transfers

Bouldin Island

Bouldin Island, shown on the right, has been fallowed for dry year water transfers  (UC Davis)

Since Metropolitan Water District announced the purchase of five Delta islands, there has been a lot of speculation about the reasons for the purchase.     Jeff Kightlinger, the CEO of Metropolitan, published an op ed in the San Jose Mercury News, in which he stated that the purpose of the purchase is to preserve Delta farmland and restore wetlands.   Kightlinger also stated that the Delta Wetlands water storage project was not one of the reasons for the purchase, and that the water rights applications for the storage project are being cancelled as part of the purchase.

Kightlinger should clarify exactly which water right applications are being cancelled as part of MWD’s purchase.  The applications to divert water for the storage project were originally filed 1987 and 1993, and the State Water Board issued permits to divert water to storage on Webb tract and Bacon Island as part of Water Rights Decision 1643 in 2001.    As part of that decision, Delta Wetlands withdrew applications to divert water to Bouldin Island and Holland Tract and agreed to cancel them.   But the existing permits do give large diversion rights on Webb Tract and Bacon Island.   In 2010, the State Water Resources Control Board staff estimated the Delta Wetlands Project had the right to divert 312,000 acre feet of water to storage from December to May, and then release it during the summer.    San Joaquin County and Central Delta Water Agency both protested the project, because of issues with seepage and levee stability on neighboring islands.   San Joaquin County entered into a settlement agreement in July 2013, and Central Delta Water Agency also settled in August 2013.    An application for a dredging permit to construct the reservoirs on Webb Tract and Bacon Island is currently pending with the Army Corps of Engineers.   There is currently no indication that this application is being cancelled.

MWD also acquires other water rights with the purchase of the five Delta islands.  In addition to the Delta Wetlands water rights, the islands have more senior water rights, including riparian, pre-1914 and appropriative.  Two  of the islands have previously had acreage fallowed for drought year water transfers.   In 2009, MWD  arranged with Delta Wetlands to fallow up to 5,426 acres on Bouldin Island and 4,189 acres on Webb tract. The fallowing allowed the transfer of up to 17,941 acre feet of water to MWD under water rights licenses 1405 and 1572.    This was about 1.9 acre feet per acre. The State Water Resources Control Board determined that no CEQA analysis of the transfer was required.

In 2014, land on Bouldin Island and Webb tract was fallowed for another drought year transfer.   This time water was transferred to four Northern California water agencies that had water stored in Semitropic water bank in Kern County.    The banked water was inaccessible without the transfers, and the water agencies stated in the application that the transfer was necessary for “health and safety” supplies.    The Northern California water agencies included Santa Clara Valley Water District, Alameda Zone 7, Alameda County Water District, and the City of Tracy.    For the 2014 transfer, Delta Wetlands estimated that up to 20,734 acre feet of water would be made available by the fallowing of up to 9,550 acres of land, about 2.2 acre feet per acre.  However, an independent report by UC Davis of the 2009 MWD transfer determined that fallowing only yielded about 0.5 acre feet per acre.

The Bureau of Reclamation objected to the 2014 transfer, stating that the calculation of over 2 acre feet per acre obtained from fallowing was not supported by the history or the available science.    The State Water Board approved the transfer, based on salinity modelling by the California Department of Water Resources, and a proposed monitoring program.


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