A Resurgence We Cant Afford

California is facing a critical water supply shift as climate change depletes traditional snowmelt-fed reservoirs, leading to an increased reliance on groundwater. The document highlights that snow is melting up to 30 days earlier than in the mid-twentieth century and that the state's surface-water storage is not designed for a future of rain-dominant precipitation. This has led to the over-pumping of aquifers, particularly in the Central Valley. To address this, the document advocates for the implementation of the Sustainable Groundwater Management Act (SGMA) of 2014, which requires local agencies to develop sustainability plans by 2020. The authors propose capturing floodwaters to recharge aquifers, which would simultaneously reduce flooding risks and provide a buffer against future droughts.

• Climate change is significantly altering California's traditional water sources, with snowpack reaching a 500-year low and melting as many as 30 days earlier than in the mid-twentieth century. This shift means less water is available during hotter months when demand is highest.
• The state's existing surface-water storage system is inadequate for future climate projections because it was designed for snowmelt rather than the expected increase in rain-dominant precipitation.
• California has increased its reliance on groundwater, which now provides between 30 and 50 percent of the state's water supply, but this has led to severe overdrafting of aquifers, especially in the Central Valley.
• Global warming is increasing the risk of extreme weather events in the region, including an 80 percent probability that the Southwest will experience a 'megadrought' lasting over 20 years between 2050 and 2099.
• Climate change may paradoxically increase both water shortages and flooding; parched land during droughts prevents rainwater infiltration, leading to violent runoff and floods that existing dams cannot effectively store.
• The Sustainable Groundwater Management Act (SGMA) of 2014 establishes the first statewide requirement for groundwater management, mandating the creation of local groundwater sustainability agencies (GSAs) by 2017 and sustainability plans by 2020.
• Sustainable groundwater management, including redesigning urban storm-water capture and rural recharge infrastructure, can mitigate both floods and droughts while reducing the energy intensity of pumping.

APA

Union of Concerned Scientists (2015). A Resurgence We Cant Afford. https://www.ucs.org/sites/default/files/attach/2015/11/california-water-supply-shift.pdf

Chicago

Union of Concerned Scientists. A Resurgence We Cant Afford. 2015. https://www.ucs.org/sites/default/files/attach/2015/11/california-water-supply-shift.pdf.

Wikipedia

{{cite report |author=Union of Concerned Scientists |title=A Resurgence We Cant Afford |date=November 2015 |url=https://www.ucs.org/sites/default/files/attach/2015/11/california-water-supply-shift.pdf |access-date=23 October 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{unionofconcernedscientists2015resurgence, author = {{Union of Concerned Scientists}}, title = {{A Resurgence We Cant Afford}}, institution = {Union of Concerned Scientists}, year = {2015}, month = nov, url = {https://www.ucs.org/sites/default/files/attach/2015/11/california-water-supply-shift.pdf}, urldate = {2026-10-23}, note = {Indexed by Climate Insights Directory} }