Publication Date:
2016-04-01
Description:
The Colorado River has been identified as the most overallocated river in the world. Considering predicted future imbalances between water supply and demand, and the growing recognition that baseflow (a proxy for groundwater discharge to streams) is critical for sustaining flow in streams and rivers, there is a need to develop methods to better quantify present-day baseflow across large regions. We adapted and applied the spatially referenced regression on watershed attributes (SPARROW) water quality model to assess the spatial distribution of baseflow, the fraction of streamflow supported by baseflow, and estimates of and potential processes contributing to the amount of baseflow that is lost during in-stream transport in the Upper Colorado River Basin (UCRB). On average, 56% of the streamflow in the UCRB originated as baseflow, and precipitation was identified as the dominant driver of spatial variability in baseflow at the scale of the UCRB, with the majority of baseflow discharge to streams occurring in upper elevation watersheds. The model estimates an average of 1.8x10 10 m 3 /yr of baseflow in the UCRB; greater than 80% of which is lost during in-stream transport to the Lower Colorado River Basin via processes including evapotranspiration and water diversion for irrigation. Our results indicate that surface waters in the Colorado River Basin are dependent on baseflow, and that management approaches that consider groundwater and surface water as a joint resource will be needed to effectively manage current and future water resources in the Basin. This article is protected by copyright. All rights reserved.
Print ISSN:
0043-1397
Electronic ISSN:
1944-7973
Topics:
Architecture, Civil Engineering, Surveying
,
Geography
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