Final EPA-USGS Technical Report: Protecting Aquatic Life from Effects of Hydrologic Alteration

U.S. Geological Survey (USGS) | December 6th, 2016

The natural flow regime of a water body, defined as its characteristic pattern of flow magnitude, timing, duration, frequency, and rate of change, plays a critical role i

The natural flow regime of a water body, defined as its characteristic pattern of flow magnitude, timing, duration, frequency, and rate of change, plays a critical role in supporting the chemical, physical, and biological integrity of streams and rivers and the services they provide. Human-induced alteration of the natural flow regime can degrade a stream’s physical and chemical properties, leading to loss of aquatic life and reduced aquatic biodiversity. Protecting aquatic life from the effects of flow alteration involves maintaining multiple components of the flow regime within their typical range of variation. This report was developed (1) to serve as a source of information for states, Tribes, and territories on the natural flow regime and potential effects of flow alteration on aquatic life and (2) to provide a flexible, nonprescriptive framework that can be used to quantify targets for flow regime components that are protective of aquatic life. As a supplementary resource, Appendix A was added to provide examples where states and Tribes have applied Clean Water Act (CWA) tools to protect aquatic life from altered flow. Anthropogenic landscape change and water management activities are modifying flood flows, base flows, peak-flow timing, and other flow characteristics in streams and rivers throughout the United States. Under natural conditions, a stream’s flow regime is determined by hydrologic properties at two scales, the upstream drainage area (catchment) and the local, reach scale. At the catchment scale, climate determines patterns of water and energy input over time, whereas physical characteristics like soils, geology, and topography determine pathways, rates of runoff, and routing through the stream network. Reach-scale factors such as local groundwater dynamics further influence natural flow regime characteristics. Human activities that alter the natural flow regime also occur at both the catchment and reach scales and include impoundments, channelization, diversions, groundwater pumping, wastewater discharges, urban development, thermoelectric power generation, and agricultural practices. Many of these activities alter hydrologic processes like infiltration, groundwater recharge, channel storage, or routing and lead to flow conditions outside the natural range of variation. Others directly add or remove water from a stream such that flows are uncommonly high or low over long periods of time. Occurring in conjunction with these activities is climate change. Climate trends observed in recent decades and future projections (for example, rising ambient air temperatures, increasing frequency of heavy precipitation events, reductions in the thickness of snow pack and ice) may magnify the effects of other anthropogenic processes on the natural flow regime. Alteration of the natural flow regime can have cascading effects on the physical, chemical, and biological properties of riverine ecosystems. Effects on physical properties include altered channel geomorphology (channel incision, widening, bed armoring, etc.), reduced (or augmented) riparian and flood-plain connectivity, and reduced (or augmented) longitudinal (upstream-downstream) and vertical (surface water/groundwater) connectivity. Effects on water quality can also result from altered flow magnitudes. For example, salinity, sedimentation, and water temperature can increase when flow volumes are reduced, whereas erosion and sediment transport can increase with amplified flow volumes. These changes to a stream can in turn lead to the degradation of aquatic life as a result of the loss and disconnection of high-quality habitat. Furthermore, altered flows can fail to provide the cues needed for aquatic species to complete their life cycles and can encourage the invasion and establishment of non-native aquatic species. The ability of a water body to support aquatic life is tied to the maintenance of key flow-regime components. Efforts to implement strategies to protect aquatic life from flow alteration will be most effective if numeric targets are identified for flow-regime components that equate to intact and healthy aquatic communities. This report presents a flexible framework that can be used to quantify flow targets that incorporate U.S. Environmental Protection Agency Guidelines for Ecological Risk Assessment (ERA) and concepts from contemporary environmental flow literature. The framework consists of eight steps that begin with identifying biological goals and assessment endpoints and end with an evaluation of effects on aquatic life under varying degrees of flow alteration. The framework does not prescribe any particular analytical approach (for example, statistical or mechanistic modeling methodology), but rather focuses on the process and information needed to evaluate relations between flow and aquatic life and the development of narrative or numeric flow targets.

Final Groundwater Assessment Study: A Status Report on the Use of Groundwater in the Service Area of the Metropolitan Water District of Southern California

Metropolitan Water District of Southern California (MWD) | September 3rd, 2007

Final Groundwater Sustainability Plan for the Yucaipa Groundwater Subbasin

San Bernardino Valley Municipal Water District | January 27th, 2022

The Yucaipa Groundwater Sustainability Agency (GSA), acting as the GSA for the Yucaipa Subbasin (Plan Area, Subbasin), developed this Groundwater Sustainability Plan (GS

The Yucaipa Groundwater Sustainability Agency (GSA), acting as the GSA for the Yucaipa Subbasin (Plan Area, Subbasin), developed this Groundwater Sustainability Plan (GSP) in compliance with the 2014 Sustainable Groundwater Management Act (SGMA) and the California Department of Water Resources (DWR) GSP Regulations. The Yucaipa Subbasin lies within the Upper Santa Ana River Basin Hydrologic Region (DWR Basin Number 8-002.07) and underlies an area of approximately 25,300 acres under portions of the cities of Calimesa, Redlands, and Yucaipa, as well as unincorporated San Bernardino and Riverside Counties. DWR designated the Yucaipa Subbasin a high priority basin based primarily on its reliance on groundwater for water supply. However, this Subbasin is not in a state of critical overdraft. Under SGMA, GSAs “have the responsibility for adopting a Plan that defines the basin setting and establishes criteria that will maintain or achieve sustainable groundwater management.” The requirement of the GSP is to maintain or achieve sustainable groundwater management in the Yucaipa Subbasin by 2042. Due to size, this file has been divided. Part 1, Part 2, Part 3, Part 4, Part 5, Part 6

Final Initial Study / Mitigated Negative Declaration PG&E’s Upper Drum-Spaulding Hydroelectric Project (FERC No. 2310) and Lower Drum Hydroelectric Project (FERC No. 14531)

California State Water Resources Control Board (SWRCB) | February 1st, 2021

The State Water Resources Control Board (State Water Board) has prepared this Initial Study/Mitigated Negative Declaration (IS/MND) to provide the public, responsible age

The State Water Resources Control Board (State Water Board) has prepared this Initial Study/Mitigated Negative Declaration (IS/MND) to provide the public, responsible agencies, and trustee agencies with information about the potential environmental effects of relicensing the two specified Pacific Gas and Electric Company (PG&E) hydroelectric projects, collectively referred to as the Proposed Projects: Upper Drum-Spaulding Hydroelectric Project (Proposed Upper Drum-Spaulding Project) - Federal Energy Regulatory Commission (FERC) Project No. 2310; and Lower Drum Hydroelectric Project (Proposed Lower Drum Project) - FERC Project No. 14531.

Final land management plan for the Yolo Bypass Wildlife Area

California Department of Fish and Wildlife (CDFW) | June 9th, 2008

The Yolo Bypass Wildlife Area (Wildlife Area) comprises approximately 16,770 acres of managed wildlife habitat and agricultural land within the Yolo Bypass (Bypass). The

The Yolo Bypass Wildlife Area (Wildlife Area) comprises approximately 16,770 acres of managed wildlife habitat and agricultural land within the Yolo Bypass (Bypass). The Bypass conveys seasonal high flows from the Sacramento River to help control river stage and protect the cities of Sacramento, West Sacramento, and Davis and other local communities, farms, and lands from flooding. Substantial environmental, social and economic benefits are provided by the Yolo Bypass, benefiting the people of the State of California. The California Department of Fish and Game (DFG), as part of the Resources Agency of the State of California, has the following mission to guide its planning and operations: “The mission of the Department of Fish and Game is to manage California’s diverse fish, wildlife, and plant resources, and the habitats upon which they depend, for their ecological values and for their use and enjoyment by the public.” The stated purpose of the Yolo Bypass Wildlife Area Land Management Plan (LMP) is to: guide management of habitats, species, appropriate public uses, and programs to achieve DFG’s mission; direct an ecosystem approach to managing the Yolo Bypass Wildlife Area in coordination with the objectives of the CALFED Ecosystem Restoration Program (ERP); identify and guide appropriate, compatible public-use opportunities within the Yolo Bypass Wildlife Area; direct the management of the Yolo Bypass Wildlife Area in a manner that promotes cooperative relationships with adjoining private-property owners; establish a descriptive inventory of the sites and the wildlife and plant resources that occur in the Yolo Bypass Wildlife Area; provide an overview of the Yolo Bypass Wildlife Area’s operation, maintenance, and personnel requirements to implement management goals, and serve as a planning aid for preparation of the annual budget for the Bay-Delta Region (Region 3); and present the environmental documentation necessary for compliance with state and federal statutes and regulations, provide a description of potential and actual environmental impacts that may occur during plan management, and identify mitigation measures to avoid or lessen these impacts. This LMP was prepared through a partnership between DFG and the Yolo Basin Foundation (Foundation) and with the benefit of an extensive public-input program. DFG provided overall guidance to the planning process and was responsible for all decisions regarding the content of the LMP. The Foundation was responsible for coordinating substantial stakeholder outreach and facilitating stakeholder input in the LMP development. The Foundation was instrumental in the development of environmental education and interpretation programs at the Yolo Bypass Wildlife Area and helped facilitate the documentation of these programs in this plan. The public-outreach program featured six focus group meetings conducted before initiation of LMP development (2002); a total of 37 Yolo Bypass Working Group Meetings (1999 to 2006; updates on developments at the Yolo Bypass Wildlife Area have been a frequent topic of discussion); one advertised public meeting for initial input (December 12, 2005, in Davis, attended by 30 persons); five additional focus group meetings to receive input on the Preliminary Draft LMP (March and April, 2006), one advertised public meeting for input on the Draft LMP and Initial Study. Appendix A provides a summary of the comments received at the public meetings and examples of the various communication devices that were used to publicize the planning process.

Final Mojave Region Integrated Regional Water Management Plan

Mojave Water Agency (MWA) | June 1st, 2014

Final Regulatory Flexibility Analysis for the Final Rule Defining "Harm" in the Definition of "Take" in the ESA

National Marine Fisheries Service (NMFS) | October 1st, 1999

The National Marine Fisheries Service (NMFS) is issuing a final rule defining the term "harm" contained in the definition of "take" under the Endangered Species Act of 19

The National Marine Fisheries Service (NMFS) is issuing a final rule defining the term "harm" contained in the definition of "take" under the Endangered Species Act of 1973 (ESA). This rulemaking will codify NMFS' interpretation of "harm" is that habitat modification can result in a take under the ESA. The Regulatory Flexibility Act (RFA), 5 U.S.C. 601 et seq. requires the preparation of an initial and final Regulatory Flexibility Analyses unless an agency determines that a rule, if promulgated, will not have a significant economic impact on a substantial number of small entities. In the May 1, 1998 Federal Register Notice for the proposed rule to define harm (63 FR 24148-24150), NMFS opined that the proposed rule, if adopted, would not have a significant economic impact on a substantial number of small entities, as described in the Regulatory Flexibility Act, and that therefore, a Regulatory Flexibility Analysis would not be required for adoption of the final rule. However, numerous public comments were received in response to the Federal Register Notice and accompanying draft EA requesting that a Regulatory Flexibility Analysis be performed. This document constitutes NMFS' Final Regulatory Flexibility Analysis.

Final Report on the recovery of the Upper Sacramento River - subsequent to the 1991 Cantara spill

Cantara Trustee Council | June 18th, 2007

The Cantara Trustee Council (CTC), and the Cantara Program, operated for a period of 12 years, from 1995-2007. During that time, the CTC funded numerous projects which in

The Cantara Trustee Council (CTC), and the Cantara Program, operated for a period of 12 years, from 1995-2007. During that time, the CTC funded numerous projects which included restoration activities, land acquisition and protection, research, and public education. The purpose of this document is to leave a summary record of events that occurred due to the 1991 Cantara spill. It is our intent to provide a condensed presentation of the spill event, the legal processes following the spill, including the formation of the CTC, the formation of the Cantara Program, and the development of guiding plans and documents used by the CTC in the disbursement of settlement funds.

Final Sensitive Beneficial Use Literature Review (Task 3.1.1)

Central Valley Salinity Alternatives for Long-Term Sustainability (CV-Salts) | May 16th, 2023

Final State Water Project Delivery Capability Report 2023

California Department of Water Resources (DWR) | July 31st, 2024

This Delivery Capability Report presents California Department of Water Resources (DWR) analysis of the State Water Project (SWP) system and provides important planning i

This Delivery Capability Report presents California Department of Water Resources (DWR) analysis of the State Water Project (SWP) system and provides important planning information for users of SWP water. The analysis provides information about how changing climate, regulatory, and operational considerations impact SWP delivery capability.