ABSTRACT:

Our ability to sustainably manage the Colorado River is clearly in doubt. The Bureau of Reclamation’s 2012 Water Supply and Demand Study demonstrated the precarious balance that currently exists between water supply and the amount consumptively used by society. A future with either declining water supplies or additional consumptive uses will undoubtedly upset this balance. This balance is threatened because: (1) climate change science predicts that watershed runoff will decline due to increased evapotranspiration from rising temperatures; and (2) water users, especially in the Upper Basin, aspire to increase consumptive uses by developing new projects. This white paper describes how declining runoff and increased consumptive use will impact water supplies and ecosystems, and also considers how these risks can be addressed.

The objective of the White Paper is to encourage wide-ranging and innovative thinking about how to sustainably manage the water supply, while simultaneously encouraging the negotiators of new agreements to consider their effects on ecosystems. To achieve this objective, we introduce a wide variety of alternative management paradigms that offer significant modifications or entirely new approaches to the status quo. Because of the magnitude and severity of the impending challenges that the basin faces, we intentionally describe and evaluate approaches that some might consider radical due to existing and assumed physical or management constraints. However, all infrastructural and institutional constraints on the Colorado River have been developed over only the last century, and to assume that decisions must remain bound by such constraints may limit our ability to identify innovative solutions needed to meet the challenges ahead. The goal of this white paper is to encourage conversation and consideration of new management concepts that will better meet future needs.

ABSTRACT:

This paper summarizes the current understanding of future hydrology from the perspective of how that understanding can be incorporated into the Colorado River Simulation System and other river planning models. We also provide scenarios that characterize and estimate plausible future drought conditions, based on the record of past droughts in historic and tree ring-estimated natural flow. Scenarios described in this report, although sometimes of low probability, are based on flows that have occurred in the past or can be reconstructed from the past record of streamflow. If such conditions have happened in the past, they might occur in the future, and these scenarios should be considered in future planning.

ABSTRACT:

The Colorado River is facing an unprecedented water supply crisis due to a 20% reduction of streamflow compared to the 20th century average and to policies that have allowed 21st century consumptive water use to exceed water supplies. To continue to meet demands, storage in the two largest reservoirs in the United States, Lakes Mead and Powell, have fallen from nearly full in 2000 to a projected level of 25% full by the end of the year. Existing drought management policies have thus far been unable to arrest this decline. If the current drought were to continue, substantially greater reductions in consumptive use will be necessary to avoid the loss of hydropower and avoid unpredictable delivery reductions to water users. To address the imbalance between supply and consumption, we identify combinations of limits on Upper Basin consumptive use alongside reduced deliveries to the Lower Basin and Mexico. These adaptation measures need to be applied swiftly to avoid further decline if the current drought persists.

This collection is supplementary data and code referenced in the journal article titled "What will it take to stabilize the Colorado River? ". This collection is to preserve and provide access to data used in the study in the interest of transparency and reproducibility of this work.

ABSTRACT:

The data set contained in this archive was developed and used to conduct a study titled 'Exploring Cooperative Transboundary River Management Strategies for the Eastern Nile Basin'. The data set includes three ensembles of hydrologic inputs, each developed from a simulated annealing technique. A baseline ensemble uses statistical properties similar to historical conditions from 1900-2002. A second ensemble increases the interannual standard deviation of all inputs by 15%. A third ensemble increases the long-term persistence of all inputs by increasing the Hurst coefficient by 20%. The data provides inputs for the Eastern Nile RiverWare Model (ENRMv3.3). The study explored cooperative management strategies between the countries of Ethiopia, Sudan and Egypt after the construction of the Grand Ethiopian Renaissance Dam using a multi-objective evolutionary algorithm. This results of this study have been published in Water Resources Research (https://doi.org/10.1029/2017WR022149).