Regional Hydrology and Geography

The Colorado River watershed area encompasses over 246,000 square miles, and flows through high mountain elevations at the headwaters in Grand Lake, Colorado, continues through the plateau regions of Dinosaur National Park, then widens through desert regions of Utah into the Grand Canyon in Arizona, and finally empties into the Gulf of Mexico, where freshwater meets the ocean seas. Because the Colorado River watershed hosts a wide range of natural processes, this section is dedicated to studies and resources on Colorado River basin hydrology and geography with special focus given to regional temperature and precipitation trends and Colrado River flow regimes. This section is organized by chronological order, starting with most recent. For other information on climate variability and change, restoration or conservation issues on the Colordo River, visit the other Colorado River Resources webpages.

Documents and Resources

Stochastic Nonparametric Framework for Basin wide Streamflow and Salinity Modeling: Application for the Colorado River Basin, James R. Prairie, PhD disertation, Department of Civil, Environmental, and Architectural Engineering, University of Colorado, 2006

Changes in Streamflow Timing in the Western United States in Recent Decades (2005)
USGS streamflow data, which has streamflow records back to the 19th century, was analyzed to determine the variance of snowmelt and streamflow timing in the Western U.S. This data show trends towards diminished snowpacks and earlier snowmelt, which may be related to global warming or other natural climate changes. Most of the changes in streamflow timing occured in the Pacific Northwest, the Sierra Nevada Mountains, and the northern Rocky Mountains. According to data of yearly spring snowmelt onset, the Colorado River Basin did not see the same consistent trends as the rest of the Western U.S. In the Lower Basin, watersheds in central and east-central Arizona have experienced earlier snowmelt by 20+ days, but in the Upper Colorado Basin, there is either no change or later snowmelt in southwest Colorado and northwest New Mexico.

Streamflow Trends in the United States
USGS determined that streamflows have increased in the United States since at least 1940. They have a network of over 1600 streamflow gauges whose data goes back 60 years or more and where discharge is primarily influenced by climate variations. Most of the increases were found in low to moderate flows in the later summer and early autumn, and interestingly, the shifts seemed to occur suddenly around 1970. The Upper Mississippi, Ohio Valley, Texas-Gulf and Mid-Atlantic regions experienced the most widespread streamflow increases, but there were very few changes in the Colorado River Basin.

Climate Fluctuations, Drought and Flow in the Colorado River Basin (2004)
A Fact Sheet published by the United States Geological Survey (USGS).

Precipitation History of the Colorado Plateau Region, 1900-2000 (2002)
A Fact Sheet published by the USGS.

Impacts of Climate Change on the Hydrology of the Colorado River System(2004)
Poster by Niklas S. Christensen and Dennis P. Lettenmaier from the University of Washington.

Assessing the Hydrological Impacts of Climate Change on the Colorado River Basin
Ongoing research by Niklas Christensen of the University of Washington's Land Surface Hydrology Group, Department of Civil and Environmental Engineering.

Since the dams: Historical ecology of the Colorado Delta (2001)
Poster presented by the C.E.A.M. at United States -Mexico Colorado River Delta Symposium, International Boundary and Water Commission.

The Colorado River Basin and Climatic Change (1993)
An EPA report by Linda Nash and Peter Gleick on the sensitivity of streamflow and water supply to variations in temperature and precipitation. (EPA 230-R-93-009)

Long-Term Surface-Water Supply and Streamflow Trends in the Upper Colorado River Basin Based on Tree-Ring Analysis (1976) by C.W. Stockton and G.C. Jacoby
The first A scientific paper which shows the historic annual flows of the Colorado River extending further into the past than we have actual gauge records. This report concludes that the estimated annual flows for the Colorado River used in creating the Colorado River Compact were higher than the average flows over the last 400 years.

The effects of future climatic changes on international water resources: the Colorado River, the United States, and Mexico (1988) by P.H. Gleick
Unless mechanisms for incorporating climatic changes into water agreements between the US and Mexico can be worked out, these changes may provoke further frictions and conflicts.

Secular Variations in Streamflow in the Western United States (1984) by David M. Meko and Charles W. Stockton

Effects of a Carbon Dioxide-Induced Climatic Change on Water Supplies in the Western United States (1983) by Roger R. Revelle and Paul E. Waggoner

Chapter from "Changing Climate" by the Carbon Dioxide Assessment Committe,
Board on Atmospheric Sciences and Climate shows that warmer air and a slight decrease in precipitation would reduce both the quantity and quality of water resources in the western US.  National Academy Press. 

The Utilization and Impacts of Climate Information on the Development and Operations of the Colorado River System (1981) by Charles W. Howe and Allan H. Murphy

Article in "Managing Climatic Resources and Risks," Panel on the Effective Use of Climate Information in Decision Making, National Research Council.  Washington, DC:  National Academy Press pp.36-44.

Impact on the Colorado River Basin and Southwest Water Supply (1977) by John A. Dracup

Chapter in “Climate, Climate Change, and Water Supply” that uses the Colorado River Basin as a case study on the prediction of the effects of climatic variability and changes on future water supplies. National Academy Press, pp. 121-132.

Photos of Lake Powell after five years of drought