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Marcus Griswold’s Blog

Scott River decision gives Californians one more tool to keep water in streams

Marcus Griswold

Posted August 25, 2014

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In a landmark decision, a California court recently declared that the public trust doctrine applies to groundwater if it alters benefits provided by navigable streams - benefits that include recreational boating, hunting, swimming, wildlife habitat, and scenic beauty. Groundwater itself is woefully unprotected in the state, but where groundwater, or any other water use alters flows in navigable streams, it could be protected in the public interest.

This decision is the third piece of the puzzle in an attempt to keep water in streams, rivers, and lakes for the benefit of the people of California. The first two historic cases established that removing water from streams that fed navigable Mono Lake violated the public trust and the second required removal of dams on non-navigable tributaries if they altered flows and thus navigability in navigable waters. While a bit piecemeal, these decisions bring the state one step closer to integrated surface water-groundwater management, but do not substitute for comprehensive statewide groundwater management policies, such as those proposed in two bills pending in the state legislature. NRDC recently submitted a letter of support for one of the proposed bills, SB 1168.

The case at issue is Environmental Law Foundation v. State Water Resources Control Board involving the Scott River in Northern California. The Scott River hosts one of the most important coho salmon spawning and rearing streams in the Klamath basin, and provides habitat for fall-run Chinook salmon and steelhead trout. For decades, long stretches of the river have gone dry, especially during the summer, the North Coast Water Board notes.  Not only does this block upstream migration of fish, but even when water is available during low flows, it is likely too warm and provides little habitat, such as preferred spawning habitat in upwelling zones where groundwater enters the river – water that is in the ideal range of 57-67 degrees Fahrenheit. When combined with low flows, these impacts spell disaster for this important salmon river.

The problem is that overuse of surface and groundwater for irrigation has left streams dewatered in late summer and early fall. The North Coast Water Board estimates that a majority of the flow at the end of Scott Valley originates from groundwater in the summer, but groundwater use has increased greatly since the 1990s. According to a 2008 study, flows in the Scott River have decreased by 40%, more than any other river in the Klamath basin, since irrigation ramped up in the late 1970s. While climate variability is thought to play a role in this decline, at least 60% is due to water use for irrigation. Most of the declines occur towards the end of the irrigation season – a UC Davis study estimates that pumping removes 11-55 cfs from streams in July and August.

How broad is this decision?

In this specific case, the decision affects new groundwater wells more than 500 feet from the river, beyond the zone of adjudicated wells. Additionally, groundwater itself was not deemed a public trust resource – rather, the case addresses groundwater pumping that impacts navigable waterways.

Groundwater feeds and impacts surface water flows throughout California.   In 2010, Howard and Merrifield mapped watersheds where flows were most dependent on groundwater levels. This map provides an indication of systems that are highly reliant on groundwater.  For instance, the Scott River was mapped as medium to high ranking for the presence of base flow-dependent ecosystems. In the San Joaquin, North Coast, Sacramento River and Tulare Lake regions groundwater supplies 50% or more of flows or volume. Additionally, areas where many groundwater dependent ecosystems are clustered occur in the North Coast, North Lahontan, and Sacramento River hydrologic regions.

Groundwater dependent index merrifield 2010.png

Groundwater dependence index

What’s next?

While the court’s decision is important, it does not substitute for effective statewide groundwater regulation in California. 

California is the only western state that does not regulate or monitor groundwater use – most of this is delegated to the counties. However, groundwater makes up 30 to 46 percent of the state's water supply, and as much as 60 percent of the state's water supply in a dry year. On top of this California has allocated 300 million acre feet more surface water than actually flows through the state’s rivers and in some rivers, such as the San Joaquin, allocations exceed flows by more than 800 percent. Groundwater will only be more coveted in the future.

It’s long past time for California to protect this critical resource.  Senator Pavley and Assemblyman Dickinson have introduced groundwater management bills that would begin to address this gaping hole in California’s water management system.  We urge the Legislature and Governor Brown to seize this opportunity and pass effective groundwater management. 

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