Southern California Agricultural Water Team

WATER SUPPLY OUTLOOK FOR 2009

2008 Water Year - A Look Back

With the close of the 2008 Water Year on September 30, 2008, California closes the book on another challenging water year and leaves the state extremely vulnerable should dry conditions persist through 2009. Northern Sierra precipitation ended at 80 percent of average, State Water Project (SWP) reservoir storage is at 70 percent of normal for this time of year and runoff was 60 percent of average. The Northern Sierra precipitation index recorded 34.9" of rain this water year. Compared to the normal annual rainfall of 50.0", Water Year 2008 is the 15th driest year out of 88 years of record. Spring was extremely dry, only 3.5" of rainfall was received between March and September making it the driest seven-month period on California record - a mere 23% of average. In terms of runoff, both the Sacramento and San Joaquin River systems are classified as Critical for this water year (lowest of 5 levels).

Storage in most of the major water supply reservoirs is significantly below average. The Sacramento and San Joaquin Valley Water Year Type indexes were both classified as Critical during Water Year 2008. At the end of the Water Year, SWP storage is 31% of capacity, 49% of average for the date. The State's major reservoirs are storing about one third of their capacity at a time they would typically be at about two thirds.

2009 Water Year Outlook

Next year "could be the worst drought in California history". Such was the testimony of the Director of the Department of Water Resources (DWR), Lester Snow at a July congressional hearing on California's drought.

Initial SWP allocation

Based on these critically low SWP storage levels, the DWR has already indicated that the "initial" 2009 allocation of SWP water supplies to Southern California could be as low as 10-15%. While the final allocation is highly likely to be higher, this initial level is even lower than this year's relatively low initial allocation of 25%. Should the final SWP allocation remain at 10%, the Metropolitan Water District (Metropolitan), the SWP's largest contractor, estimates it would have a supply deficit of nearly 700,000 acre-feet based on estimates of available 2009 SWP and Colorado River supplies, plus a sustainable level of withdrawals from storage.

Adding to the challenge of drought is the issue of threatened fish species in the Delta. Court-ordered pumping restrictions are predicted to cut the State Water Project deliveries by an estimated 450,000 to 500,000 acre-feet by year's end.

Shortage Allocation Plan, IAWP, and Effects

Metropolitan continues to develop additional supplies and fund increased conservation efforts, but has indicated that, if the SWP allocation stays at 35% or less, Metropolitan will implement its recently adopted Water Supply Allocation Plan (WSAP). The WSAP allocates limited supplies to Metropolitan's member agencies in times of shortage. Should conditions warrant, Metropolitan would declare the necessary supply allocation level at its April Board meeting. However, some Metropolitan Board members are suggesting that Metropolitan consider declaring an allocation level as early as January. Under the WSAP, the allocation would be in place for 12 months starting July 1 through the following June.

The WSAP allocates Metropolitan's limited supplies over ten levels from a 5% reduction to 50% (in 5 percent increments). The regional shortage level (Shortage Allocation Schedule - Column 1) will be determined based on several factors including water supply availability, Metropolitan water management actions, storage levels, and the availability to transfer supplies that are consistent with those outlined in its Water Surplus and Drought Management (WSDM) Plan adopted by the Board in 1999. The regional shortage percentage (Column 2) represents the required necessary reduction in Metropolitan deliveries necessary to respond to shortage conditions.

The WSAP also includes a corresponding schedule of reductions in Interim Agricultural Water Program (IAWP) deliveries (Column 3). As is the case of 2008, cuts to IAWP deliveries begin prior to any cuts in full-service, M&I deliveries. Metropolitan has already indicated that the current 30% reduction in IAWP deliveries will likely continue at the beginning of 2009 absent a significant change in supply conditions. The issue then becomes whether the WSAP will be implemented by the Metropolitan Board and, if it is, whether the regional shortage percentage is 15% or greater, which would result in greater reductions in IAWP deliveries. If the regional shortage percentage reaches 35%, all IAWP deliveries will be suspended.

Indeed, 2009 is looking to be another pivotal year for Southern California's water situation. Metropolitan has already notified growers that the IAWP cuts are likely to continue for those growers not opting out of the program.

Print this page