A Literature Review and Hypsometric Analysis to Support Decisions on Trout Management Flows on the Colorado River Downstream from Glen Canyon Dam

U.S. Geological Survey (USGS) | August 7th, 2024

Fish stranding has been studied in select rivers worldwide, often with the purpose of determining how to mitigate adverse effects of dam operations on highly valued salmo

Fish stranding has been studied in select rivers worldwide, often with the purpose of determining how to mitigate adverse effects of dam operations on highly valued salmon and trout populations. However, where a reduction in trout population size is desired by resource managers, as is the case downstream of the Glen Canyon Dam on the Colorado River, flow manipulations termed trout management flows (TMFs) may be used to optimize fish stranding and mortality. To inform the design and implementation of potential future TMFs, we reviewed relevant literature to identify key factors that influence fish stranding. We found that key factors were highly interdependent and site-specific, but general trends suggest that down-ramping (decreasing flow) at rapid rates in daytime during the late spring to summer emergence period would lead to stranding of age-0 rainbow trout in shallow shoreline habitat. A hypsometric analysis was then used to predict stranding risk for age-0 rainbow trout in Glen Canyon for a range of TMFs, which incorporated existing bathymetric data and flow and habitat suitability models. Our results indicate that a TMF with a steady high flow ranging from 12,000 to 16,000 cubic feet per second (ft3/s) combined with a minimum flow ranging from 3,000 to 5,000 ft3/s may effectively strand age-0 fish while also minimizing risk to water storage in Lake Powell and other resources. This strategy implemented under normal hydropeaking operations was predicted to lead to a substantive stranding risk when paired with low flows of 5,000 ft3/s, and especially 3,000 ft3/s. However, there remains uncertainty associated with elements of implementing an effective TMF downstream from Glen Canyon Dam. The main uncertainties include (1) the down-ramp rate that maximizes stranding of age-0 trout, (2) the duration of drawdown to maximize stranding mortality while minimizing impact to downstream resources, (3) duration of high flows required for age-0 fish to colonize newly created shoreline habitat (this is only for certain TMF hydrographs), (4) number of repetitions of TMF cycles to minimize compensatory survival response, and (5) recruitment threshold of both rainbow and brown trout populations to trigger TMF implementation.

A Machine Learning Tool for Design of Behavioral Fish Barriers in the Sacramento-San Joaquin River Delta

U.S. Geological Survey (USGS) | January 16th, 2024

Survival of out-migrating juvenile salmonids (Oncorhynchus spp.) through the Sacramento-San Joaquin River Delta averages less than 33 percent, depending on water flow thr

Survival of out-migrating juvenile salmonids (Oncorhynchus spp.) through the Sacramento-San Joaquin River Delta averages less than 33 percent, depending on water flow through the delta, and is partially governed by the distribution of fish among three Sacramento River distributaries: Sutter, Steamboat, and Georgiana sloughs. Behavioral altering structures in the junctions of the distributaries can effectively increase entrainment into favorable routes, thereby increasing through-delta (Verona to Chips Island, California) survival. The effectiveness of these structures, hence forth called “behavioral barriers,” are dependent on shape, length, location, barrier type, and water velocity, which is governed by Sacramento River discharge (hereinafter referred to as “flow”).

A multi-predator trophic database for the California Current Large Marine Ecosystem

Nature Portfolio (Springer Nature) | July 27th, 2023

A Path Forward for California’s Freshwater Ecosystems

Public Policy Institute of California (PPIC) | December 2nd, 2019

Californians rely on freshwater ecosystems for many things: water supply, hydropower, recreation, fisheries, flood risk reduction, biodiversity, and more. These ecosystem

Californians rely on freshwater ecosystems for many things: water supply, hydropower, recreation, fisheries, flood risk reduction, biodiversity, and more. These ecosystems—and the social, economic and environmental benefits they provide—are part of the state’s natural infrastructure. But they are changing in undesirable ways in response to water and land use, pollution, introduction of non-native species, and a changing climate. Declines in native biodiversity are the most direct measure of these changes, with numerous species now protected by state and federal endangered species acts (ESAs) and many times more likely to need protection in future.  For the past 40 years, the ESAs have played a prominent role in managing the state’s freshwater ecosystems. While this approach has prevented extinctions, it also places an emphasis on reducing harm to listed species, rather than improving overall ecosystem condition necessary to recover their populations. And these laws are not forward-looking enough to help species adapt to changing climate and reduce future species listings. This approach also fuels controversy and litigation due to perceptions about trade-offs between species protection and economic uses of land and water.  To maintain the benefits that Californians derive from their freshwater ecosystems—and arrest the decline of native biodiversity—a new approach is needed. We recommend that the state adopt the principles and practices of ecosystem-based management. This involves the simultaneous management of water, land, and organisms to achieve a desired ecosystem condition that benefits both native biodiversity and human well-being. The goal of ecosystem-based planning is to develop a shared vision for the ecosystem, agreement upon a common set of facts, and a unified plan to achieve it. We are not proposing major reforms to state or federal endangered species acts. Rather, we recommend a shift in the way these acts are implemented.  Ecosystem-based management relies on robust governance frameworks that are transparent, collaborative, and supported by science and secure funding. Many programs are starting to adopt its principles and practices, but much more needs to be done. Actions needed to achieve ecosystem-based objectives include setting aside water budgets for the environment and using this water to improve ecosystem condition and create multiple benefits. Binding comprehensive agreements between regulatory agencies, stakeholders, and water users—developed as part of sustainable watershed management plans—should guide implementation. These plans can be used to align agency actions and permitting and can be adopted by the State Water Board as water quality control plans.  California needs to change course in how it manages freshwater ecosystems to protect the many beneficial uses they provide. Ecosystem-based management offers a more comprehensive, flexible, and adaptive approach, and one that is compatible with existing laws. We believe this approach is better able to improve ecosystem outcomes that benefit both people and nature and respond to today’s challenges while preparing for an uncertain future. 

A Perspective on America's Vanishing Streams

Journal of the North American Benthological Society (University of Chicago Press) | March 1st, 1990

The free-flowing nature of streams in the U.S. has been dramatically altered over the past century, especially through construction of dams. The Nationwide Rivers Invento

The free-flowing nature of streams in the U.S. has been dramatically altered over the past century, especially through construction of dams. The Nationwide Rivers Inventory (NRI) estimated a total of 5,200,000 km of streams in the contiguous 48 states, but only 2% (<100,000 km) have sufficient high quality features to be worthy of federal protection status. The future of this dwindling number of high-quality streams is in doubt as proponents of development compete with conservation interests. Hydropower projects are projected to be built well into the future with a large increase in small projects (55% more than in 1988) even though the total generating capacity of the U.S. would increase only 0.3%. On the other hand, conservation efforts have resulted in increasing levels of federal protection of streams since the 1960s. "National River" or "Wild and Scenic River" status now provides protection for almost 16,000 km of streams, but only about 10% are found east of the Mississippi River. Analysis of the NRI database showed that the greatest quantity and density of high-quality streams are found in the south-Atlantic states, where streams have the least protection. The greatest number of NRI streams are found in the Coastal Plain and Central Lowland physiographic provinces. The NRI analysis showed only 42 high-quality, free-flowing (no major dams) rivers >200 km remaining in the 48 contiguous states. With continuing threats of exploitation, major conservation efforts are required to preserve these last free-flowing streams.

A practical guide to environmental flows for policy and planning (with 9 case studies)

Nature Conservancy | May 18th, 2012

Environmental flows are gaining broad recognition across the United States, and the underlying science is sufficiently developed to support regional planning and policy a

Environmental flows are gaining broad recognition across the United States, and the underlying science is sufficiently developed to support regional planning and policy applications. This report explores how six states and three interstate river basins are effectively developing and applying regionalized environmental flow criteria to water resource planning, water withdrawal permitting, and multi-dam re-operation. The broad range of approaches they relate clearly demonstrates the feasibility of integrating science-based environmental flow needs into regional water management in the absence of site-specific assessments. The case studies embrace the following principles: • Regionalized environmental flow criteria apply to all the water bodies across a state or large river basin for which site-specific criteria have not yet been established. • Flow criteria link explicitly to the health of the entire aquatic and riparian ecosystem, and are not limited to specific species. • Flow regimes mimic natural inter- and intra-annual flow variability. • The development of environmental flow criteria and the policies for their implementation are closely linked.  Defining a clear path to policy implementation from the onset ensures that the ensuing science answers the right management questions. • Flow criteria are developed through a transparent, inclusive social process informed by sound science. A structured social process for identifying, understanding, and negotiating tradeoffs is critical. To varying degrees, the Ecological Limits of Hydrologic Alteration (ELOHA) framework influenced each of the case studies. ELOHA is a flexible framework for determining and implementing environmental flows at the regional scale using existing hydrologic and biological information. Major components of ELOHA include a hydrologic foundation of streamflow data, classification of natural river types, flow-ecology relationships associated with each river type, and river condition goals.

A Practitioner’s Guide to Instream Flow Transactions in California

American Rivers | March 1st, 2016

The purpose of this guide is to help water right holders –and those assisting them – understand their options for keeping water instream in California. Th

The purpose of this guide is to help water right holders –and those assisting them – understand their options for keeping water instream in California. This guide briefly describes some of the most common types of instream flow transactions (i.e., methods for restoring flow for environmental purposes), and discusses in detail how to navigate the process of completing an instream flow dedication by changing a water right, as permitted by Water Code Section 1707. The intended audience for this document includes both water rights holders and practitioners, such as staff for land trusts, water trusts, Resource Conservation Districts (RCDs), and other organizations. This guide focuses on instream dedications via the change petition process administered by the State Water Resources Control Board (State Water Board). Other publications – for example, the Trust for Public Land’s Water Acquisition Handbook (2003) – provide a more general overview of acquiring water for environmental purposes in California. This guide will provide a description of the change petition process, and offer advice on how to navigate, troubleshoot, and work in partnership with the State Water Board and other natural resource agencies to complete an instream flow dedication.

A Review of the History of Water Use throughout the Klamath River Basin

University of California, Davis (UC Davis) | April 15th, 2003

Water in the Klamath River Basin has been put to use by humans for thousands of years. Beginning with Indian tribes that lived in the area, who used the rivers for fishin

Water in the Klamath River Basin has been put to use by humans for thousands of years. Beginning with Indian tribes that lived in the area, who used the rivers for fishing through to the European settlers who used water for mining or agriculture, Klamath water has been recognized as a precious resource. Many conflicts have risen over the past two centuries as a result. This paper will discuss the uses of water throughout the history of the Klamath River Basin culminating in the Klamath Project and its effects leading to the current Klamath Basin ‘crisis’ .

A Review of the Use of Science and Adaptive Management in California's Draft Bay Delta Conservation Plan

National Academy of Sciences (NAS) | January 1st, 2011

The San Francisco Bay Delta Estuary is a large, complex estuarine ecosystem in California. It has been substantially altered by dikes, levees, channelization, pumps,

The San Francisco Bay Delta Estuary is a large, complex estuarine ecosystem in California. It has been substantially altered by dikes, levees, channelization, pumps, human development, introduced species, dams on its tributary streams and contaminants. The Delta supplies water from the state's wetter northern regions to the drier southern regions and also serves as habitat for many species, some of which are threatened and endangered. The restoration of water exacerbated tensions over water allocation in recent years, and have led to various attempts to develop comprehensive plans to provide reliable water supplies and to protect the ecosystem. One of these plans is the Bay Delta Conservation Plan (BDCP). The report, A Review of the Use of Science and Adaptive Management in California's Draft Bay Delta Conservation Plan, determines that the plan is incomplete in a number of important areas and takes this opportunity to identify key scientific and structural gaps that, if addressed, could lead to a more successful and comprehensive final BDCP. The plan is missing the type of structure usually associated with current planning methods in which the goals and objectives are specified, alternative measure for achieving the objectives are introduced and analyzed, and a course of action in identified based on analytical optimization of economic, social, and environmental factors. Yet the panel underscores the importance of a credible and a robust BDCP in addressing the various water management problems that beset the Delta. A stronger, more complete, and more scientifically credible BDCP that effectively integrates and utilizes science could indeed pave the way toward the next generation of solutions to California's chronic water problems.

A Salton Sea Chronology (Prehistory-2015)

U.S. Bureau of Reclamation (USBR) | January 14th, 2016