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Environmental Water and the Cantankerous Bay-Delta

Challenges Facing the Sacramento-San Joaquin Delta

Repelling Salinity

One often hears during this present four-year drought about all the water being “wasted” on the Bay-Delta environmental water. The fact is that, other than the millions of acre-feet going to water supply diversions, most of the so-called “environmental water” goes to repel salinity so that water entering the Delta may be exported. Very little water is going directly to help the Bay-Delta estuary ecosystem. Last winter and spring, storm water not captured by reservoirs did reach the Delta in modest pulses. These pulses were protected to some extent by restrictions on exports required by biological opinions and state water quality standards. Other than these environmental protections that served during these short pulses to help young salmon pass through the Delta, there has been little “environmental” water for the rivers or Bay-Delta since 2012. Outflow requirements, salinity standards, and export restrictions were weakened or simply not enforced during the past three years.

All the reservoir releases were designated for water supply diversions. Over 1 MAF of Shasta releases went to Valley water contractors. Over 2 MAF of reservoir releases went to the South Delta state and federal exports. Over 1 MAF went to Delta farmers. About 1 MAF went to repelling salinity to make the 3 MAF of Delta diversions possible.

Some excellent information and discussion was presented on the topic of repelling salinity this year. One of my favorites is a YouTube video ( ) that shows how salt attacks the Delta during a typical lunar tidal period. Another is an article in the San Francisco Estuary Partnership newsletter on the Delta salt-field ( ). A great tool for viewing the dynamic Delta salinity field can be found at:

The newsletter article recalls a recent ad hoc meeting of Delta scientists, modelers, and managers trying to come up with drought mitigation strategies that “wouldn’t burn so much water to keep the salt field at bay”. In other words, they were looking for ways to export more of the reservoir water entering the Delta. Those at the meeting discussed cutting exports, opening the Delta Cross Channel gates, and ceasing operation of the Suisun Marsh salinity control gates. Other than the obvious benefit of reducing exports (contrary to the meeting’s purpose), the other two options were to eliminate key environmental protections. Jon Burau (USGS) was quoted as saying: “these would be the quickest, least expensive things we could do to save water that would also have the least impact on the ecosystem.” The cross channel gate closures are required in biological opinions and water quality standards in winter-spring to keep endangered Sacramento River salmon and steelhead from entering the Central and South Delta and being lost. The Marsh salinity gates are critical in the management of the Marsh wetland ecosystem and maintenance of Montezuma Slough’s critical habitat for the two listed smelt species.

In 2015, Department of Water Resources (DWR) added a salinity barrier to the existing array of Delta barriers: the False River Barrier was eventually installed to keep salt from entering the interior Delta through Franks Tract. At the behest of DWR and the Bureau of Reclamation, the State Water Resources Control Board weakened the salinity standard by moving the compliance point five miles from Emmaton to Threemile Slough. The Board also weakened the Delta outflow standards that keep the Low Salinity Zone out of the Delta, “saving” up to several thousand cfs. In a completely unprecedented action this summer, Reclamation actually closed the Delta Cross Channel to keep salt from the salinity control site at Threemile Slough near Rio Vista. This action was possible because of the presence of the False River Barrier. The goal for managing the Delta this year was simply to keep the salt level of South Delta exports at or below the 800 EC level.

With the Delta “scientists, modelers, and managers” who manage the Delta water system thinking in terms of water “burn”, four independent Delta ecosystem scientists recently wrote a paper on the “Challenges Facing The Sacramento-San Joaquin Delta: Complex, Chaotic, or Simply Cantankerous? “1. They describe the “Delta Problem” in terms of “wicked problems” – “Such problems can’t be ignored, defy straight-forward characterization, and have no simple solutions. Yet they must be actively managed to maximize beneficial and minimize adverse outcomes”. (From ‘DeltaChallenges-v13,’ page 6). With such divergent philosophies managing the Delta, it is no wonder the Delta Problem is perceived as “wicked”. The four scientists further conclude that “opportunities exist to conserve and restore aspects of the native system and to structure the rest of the Delta to make it more hospitable to native species. Realizing those opportunities without jeopardizing water supply is the ultimate challenge in managing the Delta.” (From ‘DeltaChallenges-v13’, page 28).

It appears that one side is intent on minimizing water “burn”, while the other deals with the resulting “wicked problems” that come from the focus on water supply.

The Solution

It is a not “wicked problem.” It is a matter of switching the focus of Delta management away from minimizing “water burn” to maximizing ecosystem health and protecting endangered fish with the water available. The Valley river and Delta water quality standards for dry and critical water years were developed to provide minimal protections. Step 1 should be to maintain and enforce these standards for streamflow, water temperature, and Delta outflow and salinity. These standards could have been retained in each of the past three years with just 10% of the 4+ MAF of reservoir water delivered for water supply. If there are really “co-equal” goals, then the ecosystem getting 10% instead of near zero is a bargain. If we want to begin recovery of the Bay-Delta ecosystem from its present near-death state, we should be considering a much larger percentage of dry year water supply to meet the “co-equal” goal.

Climate change is putting a real hurt on California water supply that is very real and likely long lasting. Hard decisions and massive investments will be needed to adjust to a more reliable water supply system. However, the ecosystems and native species of California rivers, the Delta, and the Bay should not be sacrificed in the short term for the sake of water supply. The threatened and endangered fish depending on our California ecosystems cannot wait. They need the water now to survive.