Effects of water management on the wetlands of the Colorado River Delta, Mexico

Conservation Biology (Society for Conservation Biology) | August 1st, 1996

The lower delta of the Colorado River has been severely affected by the upstream diversion of water for human use. No river water is officially appropriated to support de

The lower delta of the Colorado River has been severely affected by the upstream diversion of water for human use. No river water is officially appropriated to support delta wetlands, yet large marsh areas of conservation interest still exist below the agricultural fields in Mexico. These are supported by flood water, agricultural drainage water, municipal sewage effluent, and seawater in the intertidal zone. From 1973 to 1993 the area of freshwater and brackish marsh varied widely, from 5800 to 63,000 ha. A new opportunity exists to restore wetlands in the delta now that the upstream water impoundments on the Colorado River are filled and flood flows are once again being directed to the delta. But flood control structures now channel most of the flood water directly to the sea, and most of the effluent waters are deposited in evaporation basins rather than used to support wetlands. If the Yuma Desalting Plant in the United States becomes operational and if the Rio Hardy wetlands continue to be drained, the area of brackish wetlands could decrease to less than 2000 ha in the near future. Preserving the remaining wetlands will require a binational water management plan. The plan should maximize the benefits to wetlands of flood and irrigation return flows that enter the delta, and it should minimize flood risks.

Emergency Measures to Provde Water Resources in California and Improve Disaster Response in Certain Areas

The White House | January 24th, 2025

Empirical and Experimental Analyses of Secondary Louver Efficiency at the Tracy Fish Collection Facility: March 1996 to November 1997

U.S. Bureau of Reclamation (USBR) | January 30th, 2004

Endangered Species Status for the San Francisco Bay-Delta Distinct Population Segment of the Longfin Smelt

U.S. Fish and Wildlife Service (FWS) | July 30th, 2024

We, the U.S. Fish and Wildlife Service (Service), determine endangered species status under the Endangered Species Act of 1973, as amended (Act), for the San Francisco Ba

We, the U.S. Fish and Wildlife Service (Service), determine endangered species status under the Endangered Species Act of 1973, as amended (Act), for the San Francisco Bay-Delta distinct population segment (DPS) of longfin smelt (Spirinchus thaleichthys), a fish species of the Pacific Coast. This rule extends the protections of the Act to this DPS and adds it to the List of Endangered and Threatened Wildlife.... This final rule is available on the internet at https://www.regulations.gov. Comments and materials we received on the proposed rule are available for public inspection at https://www.regulations.gov at Docket No. FWS-R8-ES-2022-0082. Availability of supporting materials: Supporting materials we used in preparing this rule, such as the species status assessment report, are available at https://www.regulations.gov at Docket No. FWS-R8-ES-2022-0082.

Enduring Solutions on the Colorado River

Arizona State University (ASU) | August 16th, 2024

As we work to reduce water use on the post-2026 Colorado River, two paths lie open before us. One is to incentivize conservation by giving water users the chance to bank

As we work to reduce water use on the post-2026 Colorado River, two paths lie open before us. One is to incentivize conservation by giving water users the chance to bank saved water for later use. Known most commonly as Intentionally Created Surplus (ICS), and more broadly in a series of increasingly creative implementations as “Assigned Water,” this creates short term savings. But in the long run, the approach entitles the users to take the water back out of thE bank. The other involves permanent reductions – “System Water.” Water use is reduced for the benefit of the Colorado River as a whole. Investment in Assigned Water, attractive to water managers because of the allure that they can get their water back, has crowded out investment in the more durable System Water reductions that will be needed to bring the Colorado River into balance. As we develop new operating rules for the river, we need to be mindful of the differences involved. Accounting for water as Assigned Water is a means to reduce total water use in the short-term but the basin requires a means to reduce total water use over the long-term. Enduring solutions on the river can only be found by addressing overallocation, which at its most basic means that there needs to be more unassigned water in Lake Mead. Click here for Part II

Enduring Solutions on the Colorado River Part II Floating Pools and Grand Bargains

Arizona State University (ASU) | April 18th, 2025

Conserving water now in reservoir savings banks, as a hedge against future risks associated with drought and declining flows, has emerged as one of the central tools for

Conserving water now in reservoir savings banks, as a hedge against future risks associated with drought and declining flows, has emerged as one of the central tools for managing the Colorado River. The Lower Basin "Intentionally Created Surplus" program, created in the 2007 Interim Guidelines, has shown the idea's promise and given the basin nearly two decades to learn the strengths and weaknesses of the approach. With tweaks to allow similar efforts in the Upper Basin and other modifications based on what we have learned about the current ICS approach, such "Floating Pools" are one of the key tools being considered as negotiators try to thread the needle of a seven-state agreement for post-2026 Colorado River management.mDone properly, they have the potential to finesse the states' disagreement over the terms of the 1922 Colorado River Compact in a way that could avoid potentially disruptive litigation. But getting the details right will be crucial to the development of an enduring bargain that can help the basin avoid the risk of interstate litigation. Click here for Part 1

Erosion and Sediment Manual

U.S. Bureau of Reclamation (USBR) | June 4th, 2017

Engineers in the Bureau of Reclamation's Sedimentation and River Hydraulics Group provide technical assistance and conduct studies to meet the needs of other Reclamation

Engineers in the Bureau of Reclamation's Sedimentation and River Hydraulics Group provide technical assistance and conduct studies to meet the needs of other Reclamation offices and of domestic and international water resources agencies. In addition to using the latest state-of-the art technology, engineers in the Sedimentation and River Hydraulics Group often have to develop new technology, methods, and computer programs for solving erosion, sedimentation, and river hydraulic problems. All the authors of the Erosion and Sedimentation Manual are members of the Sedimentation and River Hydraulics Group. Information, computer programs, and materials included in the manual are based on proven technology existing in the literature and some of them were developed by the authors for solving practical engineering problems. The objectives of writing this manual are twofold: to summarize the authors' experience and knowledge and to share with the public what they have learned and used in solving erosion and sedimentation problems. The Erosion and Sedimentation Manual is intended for engineers with basic background and knowledge in open channel hydraulics, sediment transport, and river morphology. The manual can also be used as a reference book for university professors, graduate students, and researchers for solving practical engineering problems. This manual contains nine chapters and three appendices. Each chapter is self-contained, with an introduction, summary, and a list of references. Cross references are made to avoid duplications of materials in different chapters. Basic theories, concepts, and approaches in erosion, sediment transport, river morphology, computer modeling, and field survey are reviewed and summarized in the manual. Examples are used to illustrate how to use the methods and programs contained in the manual.

Essential Pillars for the Post-2026 Colorado River Guidelines

John Fleck | April 25th, 2025

Evaluating the Accuracy of Reclamation’s 24-Month Study Lake Powell Projections

Utah State University | February 18th, 2022

The bias for inflow predictions will likely be reduced now that the reference period includes a more recent, and somewhat drier, span of time, but projections of future i

The bias for inflow predictions will likely be reduced now that the reference period includes a more recent, and somewhat drier, span of time, but projections of future inflows are likely to remain biased, because the hydrology of the 1991-2020 reference period was still wetter than the current Millennium Drought.

Evaluation of Salinity Patterns and Effects of Tidal Flows and Temporary Barriers in South Delta Channels

California Department of Water Resources (DWR) | September 15th, 2016

There are several important water issues in the south Delta related to the San Joaquin River (SJR) inflow, Central Valley Project (CVP) and State Water Project (SWP) expo

There are several important water issues in the south Delta related to the San Joaquin River (SJR) inflow, Central Valley Project (CVP) and State Water Project (SWP) export pumping, reverse flows in Old and Middle Rivers, tidal water elevations and corresponding tidal flows in south Delta channels, effects of the temporary rock barriers that are installed seasonally by DWR in various south Delta channels, as well as the sources and longitudinal patterns of salinity caused by the net inflows, outflows, and tidal movement of water in south Delta channels. This study investigated the likely inflow locations of higher salinity water (i.e., sources) measured in Old River between the head of Old River and the Delta-Mendota Canal (DMC); the electrical conductivity (EC) at the Old River at Tracy Boulevard EC monitoring station was often the highest EC measured in the south Delta channels and has frequently exceeded the D-1641 EC objectives.