Future Role of Groundwater in California
BY HARRISON PHIPPS

Groundwater is seen by many as playing a big part in the solution to meet CaliforniaÕs growing water needs. In addition to population growth, there are currently a number of programs proposed in California that would result in significant increases in the use of groundwater.

The U.S. Bureau of Reclamation has just released the Central Valley Project Improvement Act (CVPIA) draft EIR. The intent of the CVPIA is to balance limited water resources among many different users including agricultural, municipal and fish and wildlife. All the alternatives in the EIR would reduce the average water deliveries to CVP contractors.

USBR intends to purchase surface water from willing sellers to meet the increased water needs for instream flows and refuge water supplies. As surface water is sold, land must either be retired from irrigated agricultural production or water must be pumped from wells. The EIR estimates groundwater depths will increase by varying amounts as a result of the project.

The CALFED Bay-Delta program was created to develop a plan to restore the Sacramento-San Joaquin Delta. CALFED has developed a number of alternatives to achieve its goals. Whichever alternative CALFED chooses, it will include the Ecosystem Restoration Program Plan (ERPP) also developed by CALFED. The goal of the ERPP is to restore habitat and fisheries in streams and rivers that are tributary to the Delta. Most of the watersheds identified for restoration in the ERPP would need to decrease surface water diversions in order to meet instream flow needs. In some cases the surface water reallocated to instream flow is expected to be replaced with groundwater.

In 1995 the State Water Resources Control Board (SWRCB) adopted a water quality plan for the Delta. The Plan identifies municipal and industrial, agricultural and fish and wildlife beneficial uses and specifies objectives to protect those uses. The California Department of Water Resources (DWR) and USBR have agreed to implement the objectives until SWRCB adopts a water right decision to reallocate shares of the responsibility to other parties. The SWRCB has just released its EIR that describes how it intends to reallocate water rights for diversions that affect the Delta. According to the EIR, implementation of the plan would significantly affect water supplies which would result in increased groundwater use.

The Department of Water Resources developed its Supplemental Water Purchase Program (SWPP) to help meet the water needs of the State Water Contractors. One part of the SWPP was a groundwater substitution program in which DWR would purchase surface water from willing sellers who would then switch to using groundwater. After much heated debate and opposition from northern California water interests, DWR dropped the groundwater substitution part of its program.

In addition to the above programs, the California Water Plan predicts that in the near future during normal rainfall years, the state will be short several million acre-feet of water per year due to population growth.

It is not clear how much surface water will be reallocated but it is certain that groundwater use will increase significantly as a result of proposed programs and imminent population growth.