Historically Low San Luis Reservoir Highlights Broken Water System


If you need a sign that the Sacramento-San Joaquin Delta is broken, look no further than San Luis Reservoir. Despite near-average precipitation this year and healthy storage in other north state reservoirs, San Luis is so precipitously low that deliveries were nearly shutoff in early August.

Meanwhile Shasta Lake, the state’s largest reservoir, sits at 109% of its historic average for the date.

What’s wrong with this picture? In a nutshell, we have a water system that is broken from a physical and policy standpoint.

Recent developments illustrate the problem. Earlier this year, during the El Niño storms that provided at least some respite from the drought, federal officials over-cautiously kept pumping levels very low to protect Delta smelt, which prevented water from being delivered for storage in San Luis and later to farms and cities south of the Delta.  Not long after that, other federal officials decided to reserve significant volumes of water in Shasta this summer to keep it cold for winter-run salmon. Their plan restricted releases into the Sacramento River so much that some growers were at risk of supply disruptions. Delta salinity problems exacerbated by the low flows made it extremely difficult to move water into San Luis, to the point that the Bureau of Reclamation exhausted its share of stored water in the reservoir and struggled to maintain even minimal deliveries to agricultural water users south of the Delta. Algae problems in the low reservoir are creating water quality challenges for urban users in the Santa Clara Valley that rely on San Luis.

This scenario underscores the peril of regulatory agencies focusing almost exclusively on species protection at the expense of water supply.  Moreover, efforts to protect endangered fish virtually always narrowly focus on a single element – temperature control or flows – while failing to address other important factors affecting the species. Allowing a single-stressor approach to drive water management decisions only serves to maximize conflict between species protection and water supply, while failing to adequately serve either. And we continue to lose water supply every day as a result.

No one wants to see the demise of fish species. In fact, the water community is demonstrating quite the opposite with major investments by several water agencies to improve habitat and fish passage for salmon populations. Through the Salmon Recovery Program, funded in large part by water agencies, more than 200,000 tons of gravel has been deposited into waterways, improving salmon spawning ground. Fish screens also have been built to protect fish migrating up the river to spawn.  In recent decades, entire streams have been reconfigured using comprehensive management tools to provide habitat for salmon, while protecting the ability to provide reliable water supplies, sometimes with spectacular results.

Another bright spot is the Delta Smelt Resiliency Strategy released by the Brown Administration this summer. Though still relying on unproven flow elements (this time requiring increased flows during the summer months when they would never occur naturally), the strategy emphasizes multiple stressors and puts a comprehensive, lifecycle approach to saving Delta smelt on the table for the first time.

The water community strongly supports the California policy of coequal goals. Sadly, actions by regulatory agencies continue to undermine that policy. Any one driving past San Luis Reservoir this summer can see the result.

We need a comprehensive strategy for managing water supply and our aquatic resources if we are to achieve the coequal goals. Our environment, and our economy, can’t wait.