Basin-scale water system operations with uncertain future climate conditions: Methodology and case studies

Abstract

The old and useful paradigm used by water resource engineers, that hydrology in a given place is stationary, and hence it is sufficient to look into the past to plan for the future, does not hold anymore, according to climate change projections. This becomes especially true in snow-dominated regions like California, where not only the magnitude but also the timing of streamflow could be affected by changes in precipitation and temperature. To plan and operate water resources systems at the basin scale, it is necessary to develop new tools that are suited for this nonstationary world. In this paper we develop an optimization algorithm that can be used for different studies related to climate change and water resources management. Three applications of this algorithm are developed for the Merced River basin. The first of these gives an assessment of the climate change effects on the operations of this basin considering an adaptive management strategy embedded in the optimization algorithm. In a second application we explore different long-term adaptation strategies intended to mitigate the effects of climate change. A final application is developed to determine how beneficial it is to build a new reservoir considering explicitly the uncertainty about future climate projections.