Exploring the Spatially Compounding Multi‐Sectoral Drought Vulnerabilities in Colorado's West Slope River Basins

American Geophysical Union (AGU) | November 9th, 2024

Exploring Water System Vulnerabilities in California's Central Valley Under the Late Renaissance Megadrought and Climate Change

American Geophysical Union (AGU) | April 24th, 2025

Facilitating Adaptive Management in California’s Sacramento–San Joaquin Delta

University of California, Davis (UC Davis) | July 1st, 2017

Uncertainties in understanding ecosystems increase the risk that management will fail to achieve desired results. Adaptive management is a structured, iterative applicati

Uncertainties in understanding ecosystems increase the risk that management will fail to achieve desired results. Adaptive management is a structured, iterative application of science-based knowledge to reduce uncertainties and build flexibility into decision-making. However, adaptive management is more easily planned than implemented, and it is only beginning to be applied in the California’s Sacramento–San Joaquin Delta. We draw from two assessments of adaptive management in the Delta and examples of its use elsewhere to suggest how the process can be facilitated. Although a highly structured adaptive-management process may not always be needed, several elements are essential. Adaptive management should begin by clearly identifying the problem, goals, and objectives; recognizing uncertainties; identifying decision points and alternative approaches; recognizing when adjustments are needed and having the flexibility to make them; and considering societal and political constraints. Model complexity should be matched to that of the system and management needs; experiments can help unravel causal relationships. Monitoring, analyses, and syntheses require comprehensive data-management systems. More frequent and organized communications among scientists, managers, stakeholders, and decision-makers are necessary. We propose the establishment of an “Adaptive Management Team” to coordinate efforts across the management spectrum of the Delta and to provide guidance and link individual projects to shared approaches and experiences. Reliable long-term support will be needed to assess results of management actions, adjust approaches where improvement is likely, and strive toward the legislated goals of enhancing the Delta ecosystem while also providing reliable water supplies to much of California, and doing both these things in a manner that protects values of the Delta as a place where people live and work. 

Factors Affecting the Composition and Salinity of Exports from the South Sacramento-San Joaquin Delta

California Department of Water Resources (DWR) | February 24th, 2004

The goal of this report is to identify factors affecting the composition and salinity of exports from the south Sacramento-San Joaquin Delta.  Composition is defined her

The goal of this report is to identify factors affecting the composition and salinity of exports from the south Sacramento-San Joaquin Delta.  Composition is defined here as sources of salt such as rivers and seawater. The individual objectives are to Review south Delta export composition studies; Describe the salinity trends in cross-Delta flow and the San Joaquin River - the two immediate sources of water flowing to the SWP and CVP export sites in the south Delta; Identify factors determining the export of cross-Delta flow versus the San Joaquin River; and Describe long-term salinity trends in SWP exports from the south Delta and factors affecting them.  

Feather River Hydrologic Observatory: Improving Hydrological Snowpack Forecasting for Hydropower Generation Using Intelligent Information Systems

California Energy Commission (CEC) | August 31st, 2018

Changing climatic conditions and a lack of representative snow cover data challenge the ability to accurately model and fully utilize the water resources of montane snowp

Changing climatic conditions and a lack of representative snow cover data challenge the ability to accurately model and fully utilize the water resources of montane snowpack on which California depends. This project aims to improve scientific understanding of snowpack modeling and streamflow forecasting techniques. Though relevant across industries and the state, this research focuses on hydropower applications in the North Fork of the Feather River. Central components of the project are four wireless sensor networks, installed in locations that are representative of vegetation and topography patterns across the basin. The networks collect snow, temperature, relative humidity, soil moisture, and soil temperature data every 15 minutes. By blending this information with remote sensing data and historical maps, we estimate the spatial distribution of snow water resources at high resolution. These outputs can help improve runoff forecasting tools such as the Precipitation-Runoff Modeling System (PRMS). Preliminary results show that wireless sensor networks can successfully track hydrologic states and fluxes in real time and provide a more representative picture of snowpack accumulation and melt than traditional index stations. Network data are also used to gain insight into rain-on-snow events, which are a key streamflow generation mechanism for the Feather River. The data show that the current calibration of PRMS on the Feather River could overestimate snowfall and underestimate liquid precipitation. Future steps include a sensitivity analysis of PRMS to identify its dominant parameters and conceptual limitations, as well as a full, dynamic recalibration of the model. Blended maps of snow water equivalent will also be assimilated into the model. These results will be included in the decision-support suite for PG&E, California’s largest electric and natural gas utility, and an analysis will be performed to assess results’ economic value for stakeholders in the energy and water-supply sectors. 

Fill Mead First: A Technical Assessement

Utah State University | October 11th, 2016

The Fill Mead First (FMF) plan would establish Lake Mead reservoir as the primary water storage facility of the main-stem Colorado River and would relegate Lake Powell re

The Fill Mead First (FMF) plan would establish Lake Mead reservoir as the primary water storage facility of the main-stem Colorado River and would relegate Lake Powell reservoir to a secondary water storage facility to be used only when Lake Mead is full. The objectives of the FMF plan are to re-expose some of Glen Canyon’s sandstone walls that are now inundated, begin the process of re-creating a riverine ecosystem in Glen Canyon, restore a more natural stream-flow, temperature, and sediment-supply regime of the Colorado River in the Grand Canyon ecosystem, and reduce system-wide water losses caused by evaporation and movement of reservoir water into ground-water storage. 

Fill Mead First: a technical assessment

Utah State University | November 10th, 2019

The Fill Mead First (FMF) plan would establish Lake Mead reservoir as the primary water storage facility of the main-stem Colorado River and would relegate Lake

The Fill Mead First (FMF) plan would establish Lake Mead reservoir as the primary water storage facility of the main-stem Colorado River and would relegate Lake Powell reservoir to a secondary water storage facility to be used only when Lake Mead is full. The objectives of the FMF plan are to re-expose some of Glen Canyon’s sandstone walls that are now inundated, begin the process of re-creating a riverine ecosystem in Glen Canyon, restore a more natural stream-flow, temperature, and sediment-supply regime of the Colorado River in the Grand Canyon ecosystem, and reduce system-wide water losses caused by evaporation and movement of reservoir water into ground-water storage. The FMF plan would be implemented in three phases. Phase I would involve lowering Lake Powell to the minimum elevation at which hydroelectricity can still be produced (called minimum power pool elevation): 3490 ft asl (feet above sea level). At this elevation, the water surface area of Lake Powell is approximately 77 mi2, which is 31% of the surface area when the reservoir is full. Phase II of the FMF plan would involve lowering Lake Powell to dead pool elevation (3370 ft asl), abandoning hydroelectricity generation, and releasing water only through the river outlets. The water surface area of Lake Powell at dead pool is approximately 32 mi2 and is 13% of the reservoir surface area when it is full. Implementation of Phase III would necessitate drilling new diversion tunnels around Glen Canyon Dam in order to eliminate all water storage at Lake Powell. In this paper, we summarize the FMF plan and identify critical details about the plan’s implementation that are presently unknown. We estimate changes in evaporation losses and ground-water storage that would occur if the FMF plan was implemented, based on review of existing data and published reports. We also discuss significant river-ecosystem issues that would arise if the plan was implemented.

Final Environmental Assessment Sacramento River Winter-Run Chinook Salmon Management Measures for Fisheries Managed under the Pacific Coast Salmon Fishery Management Plan

National Marine Fisheries Service (NMFS) | March 1st, 2018

Final Environmental Impact Statement Post-2026 Operational Guidelines and Strategies for Lake Powell and Lake Mead

U.S. Bureau of Reclamation (USBR) | July 31st, 2026

The Colorado River Basin (Basin) provides essential water supplies to approximately 40 million people, nearly 5.5 million acres of agricultural lands, and habitat for eco

The Colorado River Basin (Basin) provides essential water supplies to approximately 40 million people, nearly 5.5 million acres of agricultural lands, and habitat for ecological resources across seven states which includes broad areas in the Southwestern United States (U.S.) and Northwestern United Mexican States (Mexico). Prudent management of the Basin is critically important because the Colorado River is the foundation for diverse resources across a large geographic region and faces exceptional challenges from prolonged drought and future uncertainty. States, tribes, and Mexico rely on the Colorado River to support essential municipal, agricultural, environmental, cultural, and hydropower needs. These resources are now at significant risk: since the onset of the current drought in 2000, the Basin’s primary reservoirs, Lake Powell and Lake Mead, have fallen to historically low elevations. Several of the major reservoir- and water-management documents and agreements developed to guide Colorado River operations through the persistently dry conditions expire in 2026, including the 2007 Colorado River Interim Guidelines for Lower Basin Shortages and Coordinated Operations for Lake Powell and Lake Mead (2007 Interim Guidelines; Reclamation 2007), the 2019 Colorado River Drought Contingency Plans (Reclamation 2019), and key international agreements between the U.S. and Mexico. Despite the significance of these agreements, actions taken over the past two decades have not been sufficiently robust to prevent continued decline of the reservoirs through the prolonged drought. The Secretary of the Interior (Secretary), acting through the Bureau of Reclamation (Reclamation), proposes adoption of new guidelines and coordinated management strategies to address Lake Powell and Lake Mead through their full operating ranges to take effect when the current agreements expire in 2026. Volume I Executive Summary Cover, Abstract, Table of Contents, and Acronyms Chapter 1. Purpose and Need Chapter 2: Description of Alternatives Chapter 3: Affected Environment and Environmental Consequences Chapter 4: Consultation and Coordination Volumes II,  III, IV Click here to be taken to Reclamation for Supporting Appendices, Preparers, References, Glossary, and Index

Final Environmental Impact Statement: Long-Term Operation of the Central Valley Project and State Water Project Central Valley Project, California

U.S. Bureau of Reclamation (USBR) | November 15th, 2024

The United States Department of the Interior, Bureau of Reclamation (Reclamation) prepared this environmental impact statement (EIS) for the 2021 Endangered Species Act R

The United States Department of the Interior, Bureau of Reclamation (Reclamation) prepared this environmental impact statement (EIS) for the 2021 Endangered Species Act Reinitiation of Section 7 Consultation on the Long-Term Operation of the Central Valley Project (CVP) and State Water Project (SWP). This EIS is meant to inform the public and decision makers on potential federal actions by examining a range of reasonable alternatives and the potential effect on the environment. Reclamation manages the CVP. The California Department of Water Resources (DWR) manages the SWP. Collectively, the operation of the CVP and SWP provides flood control and navigation; delivers water to 30 million people; supports 4 million acres of agriculture; maintains 19 wildlife refuges on the Pacific Flyway; protects numerous iconic and endemic species such as Chinook salmon, coho salmon, steelhead, sturgeon, and smelt; generates 4.5 million megawatt hours of electricity; maintains water quality for beneficial uses in the San Francisco Bay/Sacramento–San Joaquin Delta Estuary (Bay-Delta); and supports recreation throughout Northern California.