Document Type

Article

Publication Date

8-12-2010

Publication Title

Hydrology and Earth System Sciences Discussions

Volume

7

Issue

4

First page number:

5577

Last page number:

5619

Abstract

The current drought over the Colorado River Basin has raised concerns that the US Department of the Interior, Bureau of Reclamation (Reclamation) may impose water shortages over the lower portion of the basin for the first time in history. The guidelines that determine levels of shortage are affected by forecasts determined by the Colorado Basin River Forecast Center (CBRFC). While these forecasts by the CBRFC are useful, water managers within the basin are interested in long-term projections of streamflow, particularly under changing climate conditions. In this study, a bias-corrected, statistically downscaled dataset of projected climate is used to force a hydrologic model utilized by the CBRFC to derive projections of streamflow over the Green, Gunnison, and San Juan River headwater basins located within the Colorado River Basin. This study evaluates the impact of changing climate to evapotranspiration rates. The impact to evapotranspiration rates is taken into consideration and incorporated into the development of streamflow projections over Colorado River headwater basins in this study.

Additionally, the CBRFC hydrologic model is modified to account for impacts to evapotranspiration due to changing temperature over the basin. Adjusting evapotranspiration demands over the Gunnison resulted in a 6% to 13% average decrease in runoff over the Gunnison River Basin when compared to static evapotranspiration rates.

Streamflow projections derived using projections of future climate and the CBRFC’s hydrologic model resulted in decreased runoff in 2 of the 3 basins considered. Over the Gunnison and San Juan River basins, a 10% to 15% average decrease in basin runoff is projected through the year 2099. However, over the Green River basin, a 5% to 8% increase in basin runoff is projected through 2099. Evidence of nonstationary behavior is apparent over the Gunnison and San Juan River basins.

Keywords

Climatic changes; Climatology; Drought forecasting; Droughts; Evapotranspiration; Evapotranspiration—Forecasting; Evapotranspiration—Measurement; Rivers; Streamflow

Disciplines

Civil and Environmental Engineering | Engineering | Environmental Engineering | Geotechnical Engineering

Language

English

Creative Commons License

Creative Commons Attribution 3.0 License
This work is licensed under a Creative Commons Attribution 3.0 License.

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