Recent winter storms provided a boost in water supplies for the State Water Project, but these gains are overshadowed by the amount of water we could not capture because of outdated infrastructure. If we had a modern water delivery system in place – such as the pipelines in the proposed California WaterFix – water agencies would be able to capture more water in wet years, to store for dry years. Even under the more stringent operational restrictions that have been proposed, we would still be able to capture more supplies with a modernized system than we can today.
The chart above, based on real-time data from the California Department of Water Resources and the United States Bureau of Reclamation, reflects how much water is being exported by the state and federal water projects today, an estimate of how much water would be exported with new conveyance under California WaterFix, and lastly, the total amount of water flowing into the Sacramento-San Joaquin Delta.
The State Water Project's water supply capability depends in part on how much snow falls in the northern Sierra Nevada Mountains. Throughout the winter months, the state measures how much water content is in Sierra Nevada snowpack, giving water managers a predictor of how much water they can anticipate.
The drought has required water agencies to draw down on reserves - it will take years above average rainfall to replenish what's been lost. San Luis Reservoir has recorded near-historic low storage levels and is still well below average despite winter storms.
SWC's members are projected to receive 20 percent of contracted water supplies from the State Water Project in 2017. Regardless of how much is actually delivered, SWP contractors are required to pay for 100 percent of the amount of water included in their contracts.
Public water agencies release billions of gallons of water from storage every day to keep fresh water flowing through the Delta during the drought. Agencies are able to deliver a minimal amount of this stored water to customers, but the vast majority is required to meet environmental and water quality standards in the Delta.
If stored water is not being used for water deliveries, it should be reaching San Francisco Bay. The graph above provides a breakdown of where the water went last summer based on daily monitoring data from the California Department of Water Resources and the U.S. Bureau of Reclamation.