Abstract
This study assesses potential changes in runoff of California’s eight major Central Valley water supply watersheds in the 21st century. The study employs the latest operative climate projections from 10 general circulation models (GCMs) of the Coupled Model Intercomparison Project Phase 5 (CMIP5) under two emission scenarios (RCP 4.5 and RCP 8.5) to drive a hydrologic model (VIC) in generating runoff projections through 2099. Changes in peak runoff, peak timing, seasonal (major water supply season April–July) runoff, and annual runoff during two future periods, mid-century and late-century, relative to a historical baseline period are examined. Trends in seasonal and annual runoff projections are also investigated. The results indicate that watershed characteristics impact runoff responses to climate change. Specifically, for rain-dominated watersheds, runoff is generally projected to peak earlier with higher peak volumes on average. For snow-dominated watersheds, however, runoff is largely projected to peak within the same month as historical runoff has, with little changes in peak volume during mid-century but pronounced decreases during late-century under the higher emission scenario. The study also identifies changes that are common to all study watersheds. Specifically, the temporal distribution of annual runoff is projected to change in terms of shifting more volume to the wet season, though there is no significant changing trend in the total annual runoff. Additionally, the snowmelt portion of the total annual runoff (represented by April–July runoff divided by total annual runoff) is projected to decline consistently under both emission scenarios, indicative of a shrinking snowpack across the study watersheds. Collectively, these changes imply higher flood risk and lower water supply reliability in the future that are expected to pose stress to California’s water system. Those findings can inform water management adaptation practices (e.g., watershed restoration, re-operation of the current water system, investing in additional water storage) to cope with the stress.
Highlights
Understanding potential changes and trends in future hydro-climatic variables including runoff is important for long-term water resources planning and management [1]
This study examines potential changes in runoff of California’s major water supply watersheds in the 21st century
The results indicate that watershed characteristics strongly affect runoff responses to climate change
Summary
Understanding potential changes and trends in future hydro-climatic variables including runoff is important for long-term water resources planning and management [1]. It can guide the improvement of the existing predictive tools (e.g., water supply forecasting tool) and development of new ones to better predict future hydro-climatic events. This understanding can inform the development of adaptation and mitigation plans (e.g., drought response and recovery plans) to cope with undesirable but unavoidable future changes. This understanding is crucial in semi-arid areas including. As the fifth-largest economy in the world and the home to over 39 million people [2], California faces a range of water-related challenges
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.