Effects of Snow Water Storage on Hydrologic Partitioning Across the Mountainous, Western United States

American Geophysical Union (AGU) | July 12th, 2023

The retention of snow water storage and subsequent release of stored water in summer months resulted in increased hydrologic partitioning to streamflow. If the Snow Stora

The retention of snow water storage and subsequent release of stored water in summer months resulted in increased hydrologic partitioning to streamflow. If the Snow Storage Index (SSI) decreases with future warming, the volume of water partitioned streamflow will decrease non-uniformly across the western U.S. with substantial implications for ecosystemsand agricultural, industrial, and domestic water supplies.

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.

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

Environmental Water Transactions in the Colorado River Basin: A Closer Look

Stanford University | November 14th, 2018

Over the last 30 years, the voluntary transfer of water and water rights for environmental uses has become a recognized strategy for restoring streamflow in the Western

Over the last 30 years, the voluntary transfer of water and water rights for environmental uses has become a recognized strategy for restoring streamflow in the Western United States. Historically, taking water out of a stream was a legally required element of an appropriative water right. Water rights holders who left all or a portion of their right instream to enhance fish populations, riparian habitat or recreation, risked forfeiture or diminishment of their water right. Beginning in the 1980’s, state laws began to recognize both the appropriation of new water rights for instream use and to allow the transfer and amendment of existing appropriative rights for those uses. Click here for previous report.

Essential Pillars for the Post-2026 Colorado River Guidelines

John Fleck | April 25th, 2025

Estuary News, February 2003

San Francisco Estuary Partnership (SFEP) | February 15th, 2003

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.

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

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

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.