2018 Clear Creek Technical Team Annual Report for the Coordinated Long-Term Operations Biological Opinion

Delta Stewardship Council (Delta Council) | July 1st, 2019

2022 Drought Plan Klamath Project, Oregon-California Interior Region 10, California-Great Basin

U.S. Bureau of Reclamation (USBR) | April 29th, 2022

The Klamath Project (Project) delivers water for irrigation purposes to up to approximately 230,000 acres in southern Oregon and northern California when water is availab

The Klamath Project (Project) delivers water for irrigation purposes to up to approximately 230,000 acres in southern Oregon and northern California when water is available. The Project relies upon several primary water sources to meet irrigation demands including water from Upper Klamath Lake (UKL), Clear Lake Reservoir, and Gerber Reservoir, and from the Klamath and Lost rivers. The Project’s water supplies (Project Supply or Supplies) have been impacted by the severe drought conditions currently affecting the Klamath Basin in southern Oregon and northern California. This 2022 Drought Plan describes the background for and the process of allocating the available Project Supply during the 2022 spring/summer irrigation season (April 15 through September 30, 20222), consistent with the contract priorities that exist within the Project.

2022 McKinney rain-on-wildfire event, dissolved oxygen sags, and a fish kill on the Klamath River, California

Nature Portfolio (Springer Nature) | July 9th, 2025

2022–2026 Science Action Agenda: A Vision for Integrating Delta Science

Delta Stewardship Council (Delta Council) | April 5th, 2022

2025 Annual Operating Plan for Colorado River Reservoirs

U.S. Bureau of Reclamation (USBR) | October 31st, 2024

Each year’s Annual Operating Plan (AOP) for Colorado River Reservoirs reports both on the past operations of the Colorado River reservoirs for the completed year and pr

Each year’s Annual Operating Plan (AOP) for Colorado River Reservoirs reports both on the past operations of the Colorado River reservoirs for the completed year and projected operations and releases from these reservoirs for the current (i.e., upcoming) year. Accordingly, this 2025 AOP reports on 2024 operations as well as projected operations for 2025. In recent years, additions to the Law of the River such as operational rules, guidelines, and decisions have been put into place for Colorado River reservoirs including the 1996 Glen Canyon Dam Record of Decision (ROD), the Operating Criteria for Glen Canyon Dam, the 1999 Off-stream Storage of Colorado River Water Rule (43 Code of Federal Regulations [CFR] Part 414), the 2001 Interim Surplus Guidelines addressing operation of Hoover Dam, the 2006 Flaming Gorge Dam ROD, the 2006 Navajo Dam ROD to implement recommended flows for endangered fish, the 2007 Interim Guidelines for the operations of Lake Powell and Lake Mead, the 2012 Aspinall ROD, the 2016 Glen Canyon Dam Long-Term Experimental and Management Plan Environmental Impact Statement and ROD (2016 LTEMP EIS ROD), Minutes No. 323 and 330 between the United States and Mexican Sections of the International Boundary and Water Commission (IBWC), the agreements related to the 2019 Colorado River Drought Contingency Plans (DCPs)12 as authorized by Public Law 116,  the 2024 Supplemental Environmental Impact Statement (SEIS) for Near-term Colorado River Operations ROD (2024 Interim Guidelines SEIS ROD), and the 2024 Glen Canyon Dam Long-Term Experimental and Management Plan Supplemental Environmental Impact Statement and Record of Decision (2024 LTEMP SEIS ROD).  Each AOP incorporates these and other rules, guidelines, and decisions, and reports on how the criteria contained in the applicable decision document or documents are implemented. Thus, the AOP makes projections and reports on how the Bureau of Reclamation (Reclamation) will implement these decisions in response to changing water supply conditions as they unfold during the upcoming year, when conditions become known. Congress has charged the Secretary of the Interior (Secretary) with stewardship and responsibility for a wide range of natural, cultural, recreational, and tribal resources within the Colorado River Basin. The Secretary has the authority to operate and maintain Reclamation facilities within the Colorado River Basin addressed in this AOP to help manage these resources and accomplish their protection and enhancement in a manner fully consistent with applicable provisions of federal law including the Law of the River, applicable provisions of State law, and other project-specific operational limitations. The Secretary recognized in the 2007 Interim Guidelines that the AOP provides an integrated report on reservoir operations affected by numerous federal policies: "The AOP is used to memorialize operational decisions that are made pursuant to individual federal actions (e.g., ISG [the 2001 Interim Surplus Guidelines], 1996 Glen Canyon Dam ROD, this [2007 Interim Guidelines] ROD). Thus, the AOP serves as a single, integrated reference document required by section 602(b) of the CRBPA of 1968 [Colorado River Basin Project Act of September 30, 1968 (Public Law 90-537)]16 regarding past and anticipated operations."

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 western United States snow reanalysis dataset over the Landsat era from water years 1985 to 2021

Nature Portfolio (Springer Nature) | November 7th, 2022

Water stored in mountain snowpacks (i.e., snow water equivalent, SWE) represents an important but poorly characterized component of the terrestrial water cycle. The Weste

Water stored in mountain snowpacks (i.e., snow water equivalent, SWE) represents an important but poorly characterized component of the terrestrial water cycle. The Western United States snow reanalysis (WUS–SR) dataset is novel in its combination of spatial resolution (~500 m), spatial extent (31°–49° N; 102°–125° W), and temporal continuity (daily over 1985–2021). WUS–SR is generated using a Bayesian framework with model-based snow estimates updated through the assimilation of cloud-free Landsat fractional snow-covered area observations. Over the WUS, the peak SWE verification with independent in situ measurements show correlation coefficient, mean difference (MD), and root mean squared difference (RMSD) of 0.77, −0.15 m, and 0.28 m, respectively. The effects of forest cover and Landsat image availability on peak SWE are assessed. WUS–SR peak SWE is well correlated (ranging from 0.75 to 0.91) against independent lidar-derived SWE taken near April 1st, with MD

Alternatives Report Post-2026 Operational Guidelines and Strategies for Lake Powell and Lake Mead

U.S. Bureau of Reclamation (USBR) | January 17th, 2025

In December 2007 the Secretary of the Interior adopted coordinated operating guidelines for operation of Glen Canyon Dam and Hoover Dam for an interim period that expires

In December 2007 the Secretary of the Interior adopted coordinated operating guidelines for operation of Glen Canyon Dam and Hoover Dam for an interim period that expires in 2026. To address long-term Colorado River operations after the expiration of these guidelines, the United States Department of the Interior initiated a National Environmental Policy Act process on June 16, 2023, to develop and adopt successor domestic guidelines and agreements for the operation of Glen Canyon Dam and Hoover Dam to take effect in mid-2026, before the current operational framework expires. On November 20, 2024, the Bureau of Reclamation published the range of alternatives planned for analysis in the draft environmental impact statement and committed to providing additional information in a subsequent report. This report describes these alternatives and the process for developing them in more detail. The alternatives were developed over the past year and incorporate considerable input received from the Colorado River Basin States, Colorado River Basin Tribes, conservation organizations, other federal agencies, and other stakeholders during that time. Throughout 2024, the Bureau of Reclamation worked extensively with these key partners to integrate their input into the range of alternatives. The alternatives identified in this report provide a reasonable and broad range of Colorado River operations that capture an appropriate range of potential environmental impacts from implementing new operational guidelines post-2026. Click here for USBR notes on the alternatives development process.

Analysis of Colorado River Basin Storage Suggests Need For Immediate Action

John Fleck | September 11th, 2025

Assessing the accuracy of OpenET satellite-based evapotranspiration data to support water resource and land management applications

Nature Portfolio (Springer Nature) | January 15th, 2024

Remotely sensed evapotranspiration (ET) data offer strong potential to support data-driven approaches for sustainable water management. However, practitioners require rob

Remotely sensed evapotranspiration (ET) data offer strong potential to support data-driven approaches for sustainable water management. However, practitioners require robust and rigorous accuracy assessments of such data. The OpenET system, which includes an ensemble of six remote sensing models, was developed to increase access to field-scale (30 m) ET data for the contiguous United States. Here we compare OpenET outputs against data from 152 in situ stations, primarily eddy covariance flux towers, deployed across the contiguous United States. Mean absolute error at cropland sites for the OpenET ensemble value is 15.8 mm per month (17% of mean observed ET), mean bias error is −5.3 mm per month (6%) and r2 is 0.9. Results for shrublands and forested sites show higher inter-model variability and lower accuracy relative to croplands. High accuracy and multi-model convergence across croplands demonstrate the utility of a model ensemble approach, and enhance confidence among ET data practitioners, including the agricultural water resource management community.