Posted April 12, 2005, 10:27 PM.

Colorado River supplies are used to help fill many of Riverside County's local reservoirs, including Diamond Valley Lake, and the water is supplied to most of the local water agencies across Southern California, including those in San Diego County. Fortunately, due to the near-record wet year in the region, not as much imported water will be required this year.

The other major source of imported water in the region is the state water project, which brings water from the Sierra Nevada mountains. Snowpack in the Sierra Nevadas is at near-record depths, reportedly 137% of normal as of April 1st.

Lake Powell, bordering Arizona and Utah, has been particularly hard-hit by the drought over the past five years, with the water level there down more than 150 feet from the full level, the lowest since the lake was first filled, and only 34% of capacity. This year's snowpack is projected to raise that level about 50 feet.

Downstream of Lake Powell, Lake Mead, bordering Arizona and Nevada, is only 60% full, despite having risen more than 20 feet from runoff so far this rain season. Lake Mead depends to a large degree on water released from Lake Powell.