Strategies for Managing the Colorado River in an Uncertain Future

Utah State University | January 11th, 2020

Colorado River managers and stakeholders face many uncertainties—issues such as climate change, future water demand, and evolving ecological priorities. Managers and st

Colorado River managers and stakeholders face many uncertainties—issues such as climate change, future water demand, and evolving ecological priorities. Managers and stakeholders are looking for new ways to communicate about uncertain future conditions, help cope with an uncertain future, and develop public policy when future conditions are highly uncertain. Historically, Colorado River managers have operated Lake Powell and Lake Mead under the assumption that the future natural flow regime of the Colorado River at Lee Ferry will resemble the previously observed regime, but most climate scientists believe that the flow regime is changing, and that future flows will be lower, more variable, and more uncertain.

Stream Flow and Losses of the Colorado River in the Southern Colorado Plateau

Utah State University | September 18th, 2020

A confounding uncertainty for predicting stream flow and losses in anticipation of renegotiation of the 2007 Interim Guidelines for Lower Basin Shortages concerns the acc

A confounding uncertainty for predicting stream flow and losses in anticipation of renegotiation of the 2007 Interim Guidelines for Lower Basin Shortages concerns the accuracy and precision of those data. Several key gages that are not used in CRSS and are not considered part of the standard network of gages used to manage the Colorado River offer critical insight into understanding future watershed conditions.

Subsurface Geometry of the San Andreas Fault in Southern California: Results from the Salton Seismic Imaging Project (SSIP) and Strong Ground Motion Expectations

Seismological Society of America (SSA) | August 1st, 2017

The San Andreas fault (SAF) is one of the most studied strike‐slip faults in the world; yet its subsurface geometry is still uncertain in most locations. The Salton S

The San Andreas fault (SAF) is one of the most studied strike‐slip faults in the world; yet its subsurface geometry is still uncertain in most locations. The Salton Seismic Imaging Project (SSIP) was undertaken to image the structure surrounding the SAF and also its subsurface geometry. We present SSIP studies at two locations in the Coachella Valley of the northern Salton trough. On our line 4, a fault‐crossing profile just north of the Salton Sea, sedimentary basin depth reaches 4 km southwest of the SAF. On our line 6, a fault‐crossing profile at the north end of the Coachella Valley, sedimentary basin depth is ∼2–3km∼2–3  km and centered on the central, most active trace of the SAF. Subsurface geometry of the SAF and nearby faults along these two lines is determined using a new method of seismic‐reflection imaging, combined with potential‐field studies and earthquakes. Below a 6–9 km depth range, the SAF dips ∼50°–60°∼50°–60° NE, and above this depth range it dips more steeply. Nearby faults are also imaged in the upper 10 km, many of which dip steeply and project to mapped surface fault traces. These secondary faults may join the SAF at depths below about 10 km to form a flower‐like structure. In Appendix D, we show that rupture on a northeast‐dipping SAF, using a single plane that approximates the two dips seen in our study, produces shaking that differs from shaking calculated for the Great California ShakeOut, for which the southern SAF was modeled as vertical in most places: shorter‐period (⁠T<1sT<1  s⁠) shaking is increased locally by up to a factor of 2 on the hanging wall and is decreased locally by up to a factor of 2 on the footwall, compared to shaking calculated for a vertical fault.

Summary of the Proposed Northeastern Arizona Indian Water Rights Settlement Agreement for Public Discussion Purposes

Navajo Nation Water Rights Commission | May 22nd, 2024

Supplement to the 2007 Colorado River Interim Guidelines for Lower Basin Shortages and the Coordinated Operations for Lake Powell and Lake Mead

U.S. Bureau of Reclamation (USBR) | May 6th, 2024

This ROD revises the 2007 Interim Guidelines for the near-term operation of Glen Canyon and Hoover Dams to address the potential for continued low-runoff conditions in th

This ROD revises the 2007 Interim Guidelines for the near-term operation of Glen Canyon and Hoover Dams to address the potential for continued low-runoff conditions in the Basin. Reclamation has concluded that the potential impacts of low-runoff conditions pose unacceptable risks to routine operations of Glen Canyon and Hoover Dams during the remainder of the interim period (through the end of the 2026 operating year) and that modified operating guidelines need to be expeditiously developed.

Tap Water Affordability in Arizona

Arizona State University (ASU) | February 20th, 2025

In this report, the Kyl Center for Water Policy presents a comprehensive set of tap water affordability data for community water systems (CWS) in Arizona. Communities can

In this report, the Kyl Center for Water Policy presents a comprehensive set of tap water affordability data for community water systems (CWS) in Arizona. Communities can use this study to better assess how their current and future charges for water impact low- and median-income households. Water access can be improved when water charges are designed with affordability in mind so that fewer families face the risk of disconnection due to non-payment. On the other hand, most water providers rely on fees to pay for replacing aging infrastructure and water system improvements to ensure reliability.

Tectonic evolution of the Salton Sea inferred from seismic reflection data

Nature Portfolio (Springer Nature) | July 26th, 2009

Oblique extension across strike-slip faults causes subsidence and leads to the formation of pull-apart basins such as the Salton Sea in southern California. The f

Oblique extension across strike-slip faults causes subsidence and leads to the formation of pull-apart basins such as the Salton Sea in southern California. The formation of these basins has generally been studied using laboratory experiments or numerical models. Here we combine seismic reflection data and geological observations from the Salton Sea to understand the evolution of this nascent pull-apart basin. Our data reveal the presence of a northeast-trending hinge zone that separates the sea into northern and southern sub-basins. Differential subsidence (>10 mm yr−1) in the southern sub-basin suggests the existence of northwest-dipping basin-bounding faults near the southern shoreline, which may control the spatial distribution of young volcanism. Rotated and truncated strata north of the hinge zone suggest that the onset of extension associated with this pull-apart basin began after ∼0.5 million years ago. We suggest that slip is partitioned spatially and temporally into vertical and horizontal domains in the Salton Sea. In contrast to previous models based on historical seismicity patterns, the rapid subsidence and fault architecture that we document in the southern part of the sea are consistent with experimental models for pull-apart basins.

Temporal variability in irrigated land and climate influences on salinity loading across the Upper Colorado River Basin, 1986-2017

Environmental Research Letters (IOP) | January 19th, 2024

Testimony of Wade Crowfoot, California Secretary for Natural Resources House Natural Resources Committee Subcommittee on Water, Oceans and Wildlife

Salton Sea Authority | September 24th, 2020

Thank you, Chairman Huffman and members of the Subcommittee for the opportunity to testify today on how the federal government can partner with California to inve

Thank you, Chairman Huffman and members of the Subcommittee for the opportunity to testify today on how the federal government can partner with California to invest resources and efforts to improve and ultimately revitalize conditions at the Salton Sea. I serve as Secretary of the California Natural Resources Agency (CNRA), which is charged with stewarding California’s natural, historical, and cultural resources for current and future generations. As part of that work and under the direction of Governor Gavin Newsom, our Agency is advancing projects at the Salton Sea to tackle pressing environmental issues and improve conditions for the people who live near the Salton Sea. As California’s largest body of water, the Salton Sea has served as a critical wildlife habitat for nearly 100 years, providing a key stopover spot for many special species of resident and migratory birds along the Pacific Flyway. Flows into the Salton Sea have declined in recent years, and the result is a shrinking, increasingly saline lake. As the Sea recedes, previously submerged lakebed is being exposed, reducing habitat and creating dust that can be hazardous as it dries and becomes airborne. These dust emissions present air quality issues that exacerbate public health challenges experienced by local communities in the region, which already has some of the highest childhood asthma rates.

The 1922 Compact is Now the Obvious Elephant in the Negotiating Room

John Fleck | October 6th, 2025