Impacts of dam construction on streamflows during drought periods in the Upper Colorado River Basin,Texas

The purpose of this study was to assess the impacts of dam construction on streamflow during a severe drought in the upper Colorado River basin (TX), upstream of Lake Buchanan reservoir. The region has experienced severe, prolonged droughts over the past century. To ameliorate the effects of drought, and increase water storage for use during dry periods, several dams were constructed on the mainstem and tributaries of the Colorado River upstream of Lake Buchanan since the late‐1940s. Analysis of flow at the gauge above Lake Buchanan indicated streamflow was significantly reduced during the recent drought (2009–2014), compared with streamflows during the ‘drought of record’ (1950–1957). The construction of these upstream dams reduced streamflow by intercepting and storing water. It is concluded that building reservoirs in the western portion of the basin, largely in response to past droughts, although increasing water supplies for local uses, exacerbated the downstream effects of the hydrological drought, essentially making it the worst in recorded history.