Water transfers are often characterized as a “flexible” way of ensuring that water agencies get the supplies they want, especially during periods of drought. Water transfers are premised on a “water market,” in which money is exchanged for access to water supplies.

But water transfers are not so transparent and benign as they may seem. They undercut the state’s water rights system and increase the pressure on California’s rivers and aquifers. Transfers help ensure that water “flows uphill to money” by allowing people with large amounts of capital to influence water allocation decisions, especially during dry years.

Transfers are often grouped by the California Department of Water Resources and the U.S. Bureau of Reclamation into water bank programs. These programs allow “willing sellers” in the Sacramento River Basin north of the Bay-Delta Estuary to sell water to buyers south of the Delta, most notably the Kern County Water Agency and the Westlands Water District. Through these programs, sellers often give up their surface water supplies and substitute groundwater to maintain their own crop production. This practice is potentially catastrophic for the Sacramento River Basin: The basin’s rivers and streams are connected to local aquifers, and surface flows can dwindle suddenly if excessive quantities of groundwater are pumped. Excessive exploitation of aquifers can also cause wells to go dry.


Courtesy of US Bureau of Reclamation

Significant drops in groundwater levels in the Sacramento Valley’s Tuscan Aquifer were confirmed in 1994, following seven years of low annual precipitation; this decline was due largely to excessive groundwater exports.  During this period, the Western Canal Water District and other irrigation districts in Butte, Glenn and Colusa counties exported 105,000 acre feet of water extracted from the Tuscan Aquifer to buyers outside of the area. This early experiment in the conjunctive use of groundwater (i.e., storing water in groundwater basins in wet years for use during dry years) caused a significant and immediate adverse impact on the regional environment.

Prior to the 1994 water transfers, groundwater levels had dropped but the Tuscan Aquifer and its associated groundwater basins had met the demands of local domestic and agricultural users. The water districts’ 1994 extractions, however, lowered groundwater levels throughout the Durham and Cherokee areas of eastern Butte County. The water level fell and the water quality deteriorated in the wells serving the City of Durham.  Irrigation wells failed on several orchards in the Durham area. One farm never recovered from the loss of its crop and ultimately entered into bankruptcy. Although the districts’ groundwater withdrawals were in the deep levels of the aquifer, residential wells dried up in the aquifer’s shallow zone as far north as Durham.

Subsequently, the California Water Impact Network partnered with the Butte Environmental Council and the California Sportfishing Protection Alliance to win a lawsuit against the Drought Water Bank. Most recently, C-WIN and other organizations stopped a 2009 attempt by the U.S. Bureau of Reclamation to implement a water transfer program.