Scott & Shasta River Report

The Scott and Shasta Rivers remain at the center of some of California’s most important salmon recovery and water management decisions. As the first full summer following the Klamath dam removal, 2026 is providing both encouraging signs and significant challenges. While salmon are once again recolonizing habitats throughout the Klamath Basin, the Scott and Shasta Rivers continue to experience critically low summer flows, declining water quality, and increasing pressure from groundwater pumping, surface-water diversions, and warming temperatures.

At the same time, several major regulatory and planning processes are underway that will shape these watersheds for decades to come. EPIC, along with Friends of the Shasta River, Tribes, scientists, and other NGOs, is actively participating in each of these efforts to ensure that the best available science, Tribal knowledge, and long-term watershed health guide future management decisions.

Importance of Scott and Shasta Rivers

The Scott and Shasta Rivers are among the most productive salmon tributaries remaining in the entire Klamath Basin and serve as critical sources of cold-water habitat for salmon. Following the removal of the four lower Klamath dams, these rivers have become even more important because they will help supply fish that recolonize hundreds of miles of newly reopened habitat throughout the basin. The success or failure of salmon recovery in the Scott and Shasta Rivers will therefore influence not only local ecosystems and communities, but also the long-term recovery of the Klamath River as a whole and, ultimately, the restoration of sustainable commercial, recreational, Tribal, and subsistence fisheries along the West Coast.

Current River Conditions

June brought rapidly declining flows across the Scott and Shasta watersheds. The 2026 water year demonstrates that hydrologic stress is occurring earlier than in previous years. State Water Board curtailments in the Scott River watershed began in May and early June, about two months earlier than the comparable summer curtailments issued in 2025, indicating that minimum instream flows are becoming increasingly difficult to maintain even before the hottest portion of the irrigation season. USGS stream gages show the seasonal recession accelerating throughout the month. 

The graph below shows that the Scott River flows declined from approximately 145 cubic feet per second (cfs) at the beginning of June to the upper 50 cfs range by the month’s end. Note that the minimum instream flow requirements (shown in green) in the Scott River are 125 cfs from June 1-23 and 90 cfs from June 24-30. As of June 30, the Scott River has been out of compliance for 22 days.

The Shasta River similarly declined from roughly 125 cfs to approximately 55–60 cfs before stabilizing the last week of June. Note that the minimum instream flow requirement for June on the Shasta is 50 cfs. The graph below shows that Shasta River flows have dipped below the minimum requirements four times in June. During this time, despite flows below the minimum, Grenada Irrigation District (a junior water rights holder, which should have been curtailed) continued diverting for about two more weeks. 

While flow declines are typical of seasonal recession, the magnitude we see is not, and watershed residents continue to report concerning conditions throughout both watersheds. Portions of the lower Little Shasta River are nearly dry, Big Springs Creek has experienced unusually low flows, and observers have documented extensive harmful algal blooms in portions of the lower Scott River. Water temperatures continue to rise as streamflows decline, increasing stress on juvenile salmon and steelhead during one of the most vulnerable periods of their life cycle. 

One of the most concerning observations this summer has been the rapid fluctuations and subsequent juvenile fish strandings in flows associated with the Water Board’s temporary suspension and then reinstatement of curtailments in the Scott River. As a result of the curtailment status changes, watershed residents have documented situations where short-term mandated increases in flow reconnect side channels and tributaries, allowing juvenile fish to move into habitat that later becomes disconnected when diversions resume, leaving fish stranded. This pattern occurred multiple times this year, which highlights the importance of stable instream flows and locally informed, careful water management for successful salmon recovery (not just minimum flow thresholds that are often not met).  Those improvements may have to wait for completion of the Water Board’s permanent flow-setting process.

Emergency Curtailments Continue to Protect Critical Habitat

The California State Water Resources Control Board continues implementing emergency instream flow protections in the Scott and Shasta watersheds. Earlier this month, the Board reinstated curtailments in response to declining flows and dry conditions. These emergency regulations were first adopted during the recent drought and were readopted in January 2025. More recently, Assembly Bill 263 extended the authority for these emergency regulations through January 1, 2031, or until permanent instream flow regulations are adopted.

The emergency regulations establish minimum flow requirements and authorize curtailments when streamflows fall below established thresholds. Although these emergency measures have substantially improved conditions compared to pre-regulation years, violations and inconsistent compliance remain ongoing concerns. Every drop of water matters during the summer months, and effective enforcement remains essential to protecting endangered Southern Oregon/Northern California Coast (SONCC) coho salmon, Chinook salmon, steelhead, and other aquatic species.

For the most up-to-date information regarding curtailments and planning efforts, please visit the Water Board’s Scott/Shasta Drought Information Page.

Permanent Instream Flow Standards

While emergency regulations provide immediate protection, they are not intended to be permanent. The State Water Board is currently developing long-term minimum instream flow requirements for both watersheds using new scientific studies, groundwater modeling, hydrologic analyses, and economic evaluations. This represents the most significant water policy effort affecting the Scott and Shasta Rivers since agriculture arrived in the valleys. Minimum instream flows are emergency safeguards intended to prevent catastrophic ecological collapse, and should not be mistaken for the flows needed to recover abundant salmon populations or restore healthy river ecosystems.

Along with our allies, EPIC is advocating for permanent flow standards that reflect the best available science and support healthy watershed function. We have emphasized that permanent instream flow standards should be designed not merely to prevent extinction during drought, but to restore naturally functioning river ecosystems capable of producing abundant salmon populations. Successful recovery means creating conditions that support strong annual spawning runs, high juvenile survival, improved water quality, resilient cold-water habitats, and ultimately harvestable salmon populations that once again sustain Tribal fisheries, recreational anglers, commercial fishing communities, and the broader West Coast economy.

We have engaged at every step of the process by providing extensive technical comments on the State Water Board’s new groundwater-surface water models and proposed range of flows, and we will continue to engage as the process continues. Among the issues identified are questions regarding the representation of volcanic spring systems, groundwater contributions to streamflow, pumping assumptions, temporal resolution, and the models’ ability to evaluate irrigation pumping’s impacts on individual spring complexes and interconnected surface waters. These technical issues are critical because future flow recommendations will rely heavily on these models.

New Benchmark Estimating Natural Flows

One of the most significant developments in the State Water Board’s ongoing modeling effort is the inclusion of estimates of unimpaired streamflow in the Shasta River. The underlying model estimates river flows under natural conditions before extensive groundwater pumping, surface-water diversions, and reservoir operations altered the watershed.

The preliminary modeling suggests that during the summer months, unimpaired flows at the USGS Yreka gage would average approximately 361 cfs in May, 315 cfs in June, 256 cfs in July, 244 cfs in August, and 243 cfs in September, several times greater than both current summer flows and the minimum instream flow requirements currently under consideration. Although additional work is needed to better identify how these natural flows are generated, particularly contributions from the extensive volcanic spring systems, these estimates provide an important scientific benchmark. They demonstrate that today’s heavily depleted summer hydrograph represents only a fraction of the river’s natural capacity and help establish a more objective foundation for evaluating future recovery flow recommendations.

Importantly, these findings also reinforce a central point long made by fisheries scientists and watershed advocates: the emergency minimum instream flow requirements currently in place are survival thresholds, not restoration targets. Understanding the magnitude of natural summer flows provides essential context for evaluating how much water is necessary to restore healthy river processes, maintain cold-water habitat, reconnect spring-fed reaches, improve water quality, and ultimately recover self-sustaining salmon populations capable of supporting Tribal, recreational, and commercial fisheries.

Water Quality Improvements Underway

Water quantity is only one part of the recovery equation. The North Coast Regional Water Quality Control Board has begun developing updated Waste Discharge Requirements (WDRs) for commercial agricultural operations in the Scott and Shasta River watersheds. These WDRs will replace long-standing conditional waivers and are intended to improve implementation of the existing Total Maximum Daily Loads (TMDLs) for sediment, temperature, and dissolved oxygen. These new WDRs represent an important opportunity to improve water quality while ensuring restoration investments produce measurable ecological benefits.

Looking Ahead

Several additional watershed initiatives are expected to move forward over the coming year, including:

• Development of permanent Scott and Shasta instream flow regulations by the State Water Board–estimated completion ~ 2031

• Adoption of new agricultural Waste Discharge Requirements for the Scott and Shasta Rivers by the North Coast Regional Water Board–estimated completion ~ 2028

• Implementation of updates to the North Coast Basin Plan–Soon?

• Ongoing Groundwater Sustainability Plan implementation, with formal review completion by 2028

• Continued monitoring of post-Klamath dam removal/restoration, salmon recovery, and water allocation. 

The decisions being made today for the Scott and Shasta Rivers will shape the future of the entire Klamath Basin for generations. Following the historic removal of the lower Klamath dams, these watersheds now represent one of the greatest opportunities for salmon recovery anywhere on the West Coast. Real recovery, however, will require more than simply avoiding extinction or meeting minimum regulatory thresholds. It will require restoring the cold, clean, connected rivers necessary to produce abundant, self-sustaining salmon populations capable of supporting Tribal cultural practices, recreational and commercial fisheries, thriving local communities, and resilient ecosystems.

EPIC will continue advocating for science-based water management that protects groundwater and surface water together, improves water quality, restores ecological function, and ensures that future instream flow standards are designed not only for minimum survival, but for full recovery. Healthy rivers create healthy fisheries, healthy communities, and a healthier Klamath Basin for generations to come.