Outmigration survival of wild Chinook salmon smolts through the Sacramento River during historic drought and high water conditions

Environmental Biology of Fishes (Springer) | January 27th, 2020

Patterns and magnitude of flow alteration in California, USA

Freshwater Biology (Wiley) | December 27th, 2017

The importance of the natural flow regime to stream and river health has received growing attention over the last two decades. Quantifying natural river flows has become

The importance of the natural flow regime to stream and river health has received growing attention over the last two decades. Quantifying natural river flows has become an essential component of water resource planning, including assessments of water supplies (Vicuna,Maurer, Joyce, Dracup, & Purkey, 2007; Wurbs, 2005), reservoir operations (Hejazi, Cai, & Ruddell, 2008) and drought risk (Meko,Therrell, Baisan, & Hughes, 2001). Understanding the natural flow regime is also crucial for managing stream ecosystems.

Petition For Rulemaking to Set Minimum Flows on the Shasta River

Mount Shasta Bioregional Ecology Center | January 20th, 2024

Decades of scientific inquiry make clear that adequate quality and quantity of flows are needed to prevent remaining fish populations from further decline. Yet this scien

Decades of scientific inquiry make clear that adequate quality and quantity of flows are needed to prevent remaining fish populations from further decline. Yet this science is not self-executing; effective government intervention is necessary to prevent the extirpation of salmonids in the Shasta. This type of government action is at the core of the Public Trust Doctrine, which requires the government to act as a trustee over public trust resources, and to the extent feasible, step in to protect these resources from over-allocation and over-use.

Policy for Maintaining Instream Flows in Northern California Streams

California State Water Resources Control Board (SWRCB) | September 28th, 2010

The State Water Resources Control Board (State Water Board or Board) adopted this state policy for water quality control on May 4, 2010. This policy is also known as the

The State Water Resources Control Board (State Water Board or Board) adopted this state policy for water quality control on May 4, 2010. This policy is also known as the North Coast Instream Flow Policy. It applies to applications to appropriate water, small domestic use and livestock stockpond registrations, and water right petitions. Water Code section 1259.4, which was added by Assembly Bill 2121 (Stats. 2004, ch. 943, § 3), requires the State Water Board to adopt principles and guidelines for maintaining instream flows in northern California coastal streams as part of state policy for water quality control, for the purposes of water right administration. This policy implements Water Code section 1259.4. The geographic scope of this policy, referred to as the policy area, extends to five counties—Marin, Sonoma, and portions of Napa, Mendocino, and Humboldt counties— and encompasses (1) coastal streams from the Mattole River (originating in Humboldt County) to San Francisco, and (2) coastal streams entering northern San Pablo Bay. This policy focuses on measures that protect native fish populations, with a particular focus on anadromous salmonids (e.g., steelhead trout, coho salmon, and chinook salmon) and their habitat. Beginning in 1996, the National Marine Fisheries Services (NMFS) and the California Department of Fish and Game (DFG) listed steelhead trout, coho salmon, and chinook salmon as “threatened” under the federal Endangered Species Act (ESA) and the California Endangered Species Act (CESA), respectively. In 2005, the coho salmon’s status was upgraded from threatened to “endangered” on both the ESA and the CESA lists. This policy establishes principles and guidelines for maintaining instream flows for the protection of fishery resources. It does not specify the terms and conditions that will be incorporated into water right permits, licenses, and registrations. It prescribes protective measures regarding the season of diversion, minimum bypass flow, and maximum cumulative diversion. Applicants may choose to implement the policy principles through the regionally protective criteria or site-specific studies. Site-specific studies may be conducted to develop alternative site-specific protective criteria. The policy also limits construction of new onstream dams and contains measures to ensure that approval of new onstream dams does not adversely affect instream flows needed for fishery resources. The policy provides for a watershed-based approach to evaluate the effects of multiple diversions on instream flows within a watershed as an alternative to evaluating water diversion projects on an individual basis. Enforcement requirements contained in this policy include a framework for compliance assurance, prioritization of enforcement cases, and descriptions of enforcement actions. The policy contains guidelines for evaluating whether a proposed water diversion, in combination with existing diversions in a watershed, may affect instream flows needed for the protection of fishery resources.

Recent advances in understanding flow dynamics and transport of water-quality constituents in the Sacramento–San Joaquin River Delta

University of California, Davis (UC Davis) | December 1st, 2016

This chapter describes advances during the past decade in understanding flow dynamics and how water-quality constituents, such as salinity, heat, oxygen, nutrients, conta

This chapter describes advances during the past decade in understanding flow dynamics and how water-quality constituents, such as salinity, heat, oxygen, nutrients, contaminants, and more, move within California’s Sacramento-San Joaquin River Delta. Water-quality constituents are affected by water diversions and other human manipulations of flow and they greatly affect the quantity and quality of habitats in the Delta. Along with human intervention, the Pacific Ocean, the Central Valley watershed, and the atmosphere, are a few drivers of flow and transport in the Delta. These drivers provide a conceptual framework for presenting recent findings. The tremendous expansion of acoustic and optical instruments utilized in the Delta over the past decade has greatly improved our understanding of how tidal variability affects flow and transport. Sediment is increasingly viewed as a diminishing resource needed to sustain habitat and tidal marsh, especially as sea level rises. Connections between the watershed, Delta, and San Francisco Bay that have been studied recently highlight that a landscape view of this system is needed rather than consideration of each region individually. Interactions of multiple drivers and information gaps are discussed.

Review of CDFW Recommendations for the 2022 Readoption of Drought Emergency Regulations on the Scott River and Recommendations for Future Management During Extreme Drought Conditions

Siskiyou Farm Bureau | August 31st, 2022

Review of SWRCB’s “Working Draft Scientific Basis Report for New and Revised Flow Requirements on the Sacramento River and Tributaries, Eastside Tributaries to the Delta, Delta Outflow, and Interior Delta Operations”

Delta Stewardship Council (Delta Council) | February 23rd, 2017

Insightful, informative, well-illustrated, clearly written—these are among our overall impressions of “Working Draft Scientific Basis Report for New and Revised Flow

Insightful, informative, well-illustrated, clearly written—these are among our overall impressions of “Working Draft Scientific Basis Report for New and Revised Flow Requirements on the Sacramento River and Tributaries, Eastside Tributaries to the Delta, Delta Outflow, and Interior Delta Operations”. The comments below focus on recommended improvements. In particular, we recommend clarifying, and further justifying scientifically, the proposed use of percent of “unimpaired flow” as the main basis for establishing an annual environmental water budget. We also suggest presenting a further review of cold-water management, a deeper analysis of non-flow stressors, additional consideration of near-term responses to climate change, and elaboration of how regulations managed adaptively may improve scientific understanding of environmental flows.

Reviving Central Valley Rivers

CALFED | June 1st, 2003

River Meandering

American Geophysical Union (AGU) | January 1st, 1989

Published by the American Geophysical Union as part of the Water Resources Monograph Series, Volume 12. River channel pattern comes in three flavors: straight, meander

Published by the American Geophysical Union as part of the Water Resources Monograph Series, Volume 12. River channel pattern comes in three flavors: straight, meandering, and braided. Of these, meandering is perhaps the most common, but at the same time the most mysterious: it is strikingly rich in pattern, yet is encumbered with neither the sterile order of its straight cousin, nor the undecipherable disorder of its braided relative. Consider Figures 1 and 2 herein. The former is of the artificially straightened Naka River, Shikoku, Japan. Thwarted in its quest for a meandering planform, the river has, nevertheless, generated of its own the precursor known as alternate bars. In the latter photograph, a pair of images of the East Nishnabotna River, Iowa, USA, illustrate the elegance of the sinuous river, and the inexorable migration and deformation of bends so characteristic of freely meandering streams.

River-Aquifer Interactions, Geologic Heterogeneity, and Low-Flow Management

U.S. Geological Survey (USGS) | ?

Low river flows are commonly controlled by river-aquifer exchange, the magnitude of which is governed by hydraulic properties of both aquifer and aquitard mater

Low river flows are commonly controlled by river-aquifer exchange, the magnitude of which is governed by hydraulic properties of both aquifer and aquitard materials beneath the river. Low flows are often important ecologically. Numerical simulations were used to assess how textural heterogeneity of an alluvial system influences river seepage and low flows. The Cosumnes River in California was used as a test case. Declining fall flows in the Cosumnes River have threatened Chinook salmon runs. A ground water–surface water model for the lower river basin was developed, which incorporates detailed geostatistical simulations of aquifer heterogeneity. Six different realizations of heterogeneity and a homogenous model were run for a 3-year period. Net annual seepage from the river was found to be similar among the models. However, spatial distribution of seepage along the channel, water table configuration and the level of local connection, and disconnection between the river and aquifer showed strong variations among the different heterogeneous models. Most importantly, the heterogeneous models suggest that river seepage losses can be reduced by local reconnections, even when the regional water table remains well below the riverbed. The percentage of river channel responsible for 50% of total river seepage ranged from 10% to 26% in the heterogeneous models as opposed to 23% in the homogeneous model. Differences in seepage between the models resulted in up to 13 d difference in the number of days the river was open for salmon migration during the critical fall months in one given year.