Scenarios of Future California Water Demand Through 2050

This paper describes the application of future scenarios for Water Plan Update 2013 (DWR 2013) to quantify future water demand for California and our 10 hydrologic regions out to the year 2050. Starting with the publication of California Water Plan Update 2005 (DWR 2005), DWR has applied the concept of scenarios to describe future water management conditions. Scenarios are used to capture a broad range of uncertain factors that affect water management that are considered to be beyond the control of water managers. For Update 2013 scenarios were organized around narrative themes of growth and climate change, which were then quantified using factors about future population growth, housing densities, land use patterns, and climate. 

For Updates 2005 and 2009, DWR attempted only to quantify future water demand management strategies at the hydrologic region scale. The hydrologic regions are large areas of tens of thousands square miles, too large to compute meaningful information on regional water management actions. But in parallel to the hydrologic region scale analysis as in current Update 2013, DWR has been pursuing a longer term project, to perform a more complete hydrologic analysis at the finer planning area scale. Results and analysis of planning area water management strategies is given in a separate report. 

In addition to this paper, background information on the application of scenarios can be found in Chapter 5 and 6 of Update 2013. Chapter 5 provides information how scenarios are used to quantify water management uncertainty. Chapter 6 describes DWR’s efforts to effect long term improvements in data and analytical tools to support the Water Plan.