Colorado River Basin Ten Tribes Partnership Tribal Water Study

U.S. Bureau of Reclamation (USBR) | December 13th, 2018

The Colorado River Basin Tribes Partnership (a.k.a. Ten Tribes Partnership) and the Bureau of Reclamation (Reclamation) initially undertook the Colorado River Basin Triba

The Colorado River Basin Tribes Partnership (a.k.a. Ten Tribes Partnership) and the Bureau of Reclamation (Reclamation) initially undertook the Colorado River Basin Tribal Water Study to augment the data produced for the Colorado River Basin Supply and Demand Study of 2012. With five tribes in the Upper Basin and five tribes in the Lower Basin, and between us, holding rights to more than 2.8 million acre-feet per year of water from the Colorado River and its tributaries, the Ten Tribes Partnership was uniquely positioned to explore these issues. However, in so doing, we learned that the effort would also serve to facilitate a broader and, we hope, a better understanding of the role tribal water plays, and will play, in the Colorado River Basin over the coming decades. In addition to producing technical information, the Tribes had other goals. First, we wanted to better understand how, at present, each of our individual water use scenarios fits into the overall scheme of Colorado River Basin management. Second, we wanted to know how future development of tribal water resources will alter Basin operations and affect other water users who are now using water to which a tribe may hold legal title, but which the title-holding tribe has not yet developed for its own use. Finally, we wanted to assess – to the extent present information allows – the role future development of tribal water rights will have on Basin operations. Along the way, we encountered data gaps, modeling limitations, and uncertainties, but nonetheless, with the support of Reclamation, we managed to address those issues sufficiently that we now provide this Report. If there is a ‘take-away’ that was surprising, it is that, even under the most favorable of circumstances for rapid tribal water development, the amount of water that will be used by the Tribes is dramatically overshadowed by the effect of climatic conditions on the overall supply of water in the Basin. Nature is still in charge. Challenges remain, but opportunities are in the offing. We hope this Report informs, resolves some uncertainty about how tribes perceive the future for their water uses, and establishes a baseline for discussions and development of relationships among tribes, states, the federal government, water managers, and water users throughout the Basin.

Colorado River Compact, 1922

U.S. Bureau of Reclamation (USBR) | November 24th, 1922

Colorado River Drought Contingency Plan Authorization

United States Congress | April 16th, 2019

Authorized Drought Contingency Plans (DCPs) for the Upper and Lower Colorado River Basins, which required reduced Lower Basin deliveries beyond previous curtailment plans

Authorized Drought Contingency Plans (DCPs) for the Upper and Lower Colorado River Basins, which required reduced Lower Basin deliveries beyond previous curtailment plans at specified Lake Mead storage levels, committed Reclamation to additional water conservation efforts, and put in place plans to coordinate Upper Basin operations to enhance Lake Powell storage levels and prevent the loss of hydropower generation.

Colorado River flow dwindles as warming-driven loss of reflective snow energizes evaporation

American Association for the Advancement of Science (AAAS) | February 20th, 2020

The sensitivity of river discharge to climate-system warming is highly uncertain and governing processes are poorly understood, impeding climate-change adaptation. A prom

The sensitivity of river discharge to climate-system warming is highly uncertain and governing processes are poorly understood, impeding climate-change adaptation. A prominent exemplar is the Colorado River, where meteorological drought and warming have been shrinking a water resource that supports more than US$1 trillion per year of economic activity. Monte-Carlo simulation with a radiation-aware hydrologic model resolves the longstanding, wide disparity in sensitivity estimates and reveals the controlling physical processes. We estimate that annual-mean discharge has been decreasing by 9.3% per °C of warming due to increased evapotranspiration, mainly driven by snow loss and consequent decrease of reflection of solar radiation. Projected precipitation increases likely will not suffice to counter fully the robust, thermodynamically induced drying. Increasing risk of severe water shortages is expected.

Colorado River Shortage FAQs

Arizona Department of Water Resources (ADWR) | August 1st, 2022

Colorado River Storage Project of 1956

U.S. Bureau of Reclamation (USBR) | April 11th, 1956

Colorado River water supply is predictable on multi-year timescales owing to long-term ocean memory

Nature Portfolio (Springer Nature) | October 9th, 2020

Skillful multi-year climate forecasts provide crucial information for decision-makers and resource managers to mitigate water scarcity, yet such forecasts remain challen

Skillful multi-year climate forecasts provide crucial information for decision-makers and resource managers to mitigate water scarcity, yet such forecasts remain challenging due to unpredictable weather noise and the lack of dynamical model capability. Here we demonstrate that the annual water supply of the Colorado River is predictable up to several years in advance by a drift-free decadal climate prediction system using a fully coupled climate model. Observational analyses and model experiments show that prolonged shortages of water supply in the Colorado River are significantly linked to sea surface temperature precursors including tropical Pacific cooling, North Pacific warming, and southern tropical Atlantic warming. In the Colorado River basin, the water deficits can reduce crop yield and increase wildfire potential. Thus, a multi-year prediction of severe water shortages in the Colorado River basin could be useful as an early indicator of subsequent agricultural loss and wildfire risk.

Comparison of U.S. Geological Survey and Bureau of Reclamation Water-Use Reporting in the Colorado River Basin

U.S. Geological Survey (USGS) | September 2nd, 2019

The use of water in the United States is arguably one of the most important factors determining water availability at any specific place and time. Numerous local, State,

The use of water in the United States is arguably one of the most important factors determining water availability at any specific place and time. Numerous local, State, and Federal entities develop, compile, and report water-use data, which can lead to confusing or conflicting information. This report was authored jointly by the U.S. Geological Survey (USGS) and Bureau of Reclamation (Reclamation) to compare and contrast the two agencies’ water-use information programs in the Colorado River Basin. The report also describes the legal drivers for each program, clarifies confusing terminol- ogy, compares the methods used, and contrasts the information reported by each agency. This detailed comparison demon- strates that these two Federal agencies have different missions, different programmatic drivers, and different user communi- ties, all of which lead to different approaches to water-use data collection, analysis, and reporting. This report highlights those differences and explains why the USGS and Reclamation programs exist and how the data serve different user communities. Even though the two water-use programs are different by design and purpose, the program comparison presented in this report has identified opportunities for closer coordination and sharing of information between the USGS and Reclamation, as well as program components where agency collaboration can improve water-use estimate methodologies. This comparison effort emphasizes that it is incumbent upon each agency to clearly define the meaning of the terms used and the appropri- ate application of the reported information to avoid confusion or the accidental misuse of the information. An additional benefit of this comparison effort is the formation of a joint USGS/ Reclamation water-use team that will continue to investigate opportunities to expand and coordinate future water-use data compilation and reporting.

Curbing the Colorado

Scientific American | April 1st, 1922

Already, the electrical engineer has shown how the snows of the high Sierras can be transformed into energizing current distributable for hundreds of miles through a S

Already, the electrical engineer has shown how the snows of the high Sierras can be transformed into energizing current distributable for hundreds of miles through a State which i s notably deficient in deposits of power-producing coal. Similarly, this same technicist is busy planning ways by which the widely diversified flow of the second largest of our rivers, the Colorado, may be stabilized and utilized to operate a number of immense, hydroelectric stations. The Colorado River drains a watershed covering fully 250,000 square miles, and in the course of a twelvemonth its run-off  amounts to 16,000,000 acre-feet of water. The States affected by the movement of the Colorado are Nevada, Utah, Wyoming, Colorado, New Mexico, and California. Normally, the Colorado runs to extremes : in dry seasons it is low and its speed of travel comparatively sluggish, but when the melting snows and rains of the wet months pour their fullness into the far-flung basin the river becomes a raging, torrential stream capable of doing an enormous amount of damage. Uncontrolled, this great waterway is a continual menace to the lives and the property of dwellers in the Imperial Valley and in the adjacent lands, lying below the level of the sea and situated both in the United States and in Mexico.

Declining groundwater storage expected to amplify mountain streamflow reductions in a warmer world

Nature Portfolio (Springer Nature) | May 23rd, 2024

Groundwater interactions with mountain streams are often simplified in model projections, potentially leading to inaccurate estimates of streamflow response to climate ch

Groundwater interactions with mountain streams are often simplified in model projections, potentially leading to inaccurate estimates of streamflow response to climate change. Here, using a high-resolution, integrated hydrological model extending 400 m into the subsurface, we find groundwater an important and stable source of historical streamflow in a mountainous watershed of the Colorado River. In a warmer climate, increased forest water use is predicted to reduce groundwater recharge resulting in groundwater storage loss. Losses are expected to be most severe during dry years and cannot recover to historical levels even during simulated wet periods. Groundwater depletion substantially reduces annual streamflow with intermittent conditions predicted when precipitation is low. Expanding results across the region suggests groundwater declines will be highest in the Colorado Headwater and Gunnison basins. Our research highlights the tight coupling of vegetation and groundwater dynamics and that excluding explicit groundwater response to warming may underestimate future reductions in mountain streamflow.