Wildlands in California (CA), and across the western US are changing rapidly in hydrologically relevant ways. Decades of fire suppression have allowed forests to become unnaturally dense; this density is thought to have contributed to the extensive drought-induced mortality and high-intensity wildfires in the Sierra Nevada. Over the next century, climate change will further impact forest vegetation by a decrease in vegetative thermal limitations and an increase in water limitation, especially at mid-and-high elevations. A warming climate is expected to shift plant distribution as species expand in newly favorable areas and decline in increasingly hostile locations. Our INFEWS (Integrated Nexus of Food-Energy-Water System) researchers will investigate and monitor the health of wildlands regarding characteristic fluctuations lured by climate change.
Water storage capacity is an essential tool for sustaining the FEWS (Food-Energy-Water System). The state has ~40 million acre-feet (MAF) of surface reservoir storage capacity that aids water supply, flood protection, hydropower, recreational uses, and helps regulate environmental water flows for fish. Californias largest surface “reservoir” is the Sierra Nevada snowpack, averaging 15 MAF, six-months out of the year. By the end of the century, snowpack is projected to reduce by 48-65% as a result of climate change, impacting water supply and even hydropower generation.
Changes in precipitation phase, from snow to rain, will increase flooding risk and shift reservoir management from storage to flood protection. Current surface water storage is not enough to meet the 82 MAF/year of total applied water uses, barely enough to meet the 44 MAF/year of applied agriculture and urban water uses. As a result, the region relies heavily on groundwater extraction (12-20 MAF/year more during dry years versus wet years), most of which goes to supplement agriculture and urban uses. Irrespective of wet or dry years, the groundwater is continuously depleting at an average rate of 9 MAF/year. Meanwhile, the state has imposed the Sustainable Groundwater Management Act (SGMA), aiming to regulate groundwater, empowering local agencies to adopt groundwater management plans that are tailored to the resources and needs of their communities. Local groundwater plans must be development and implementation by 2022, and groundwater sustainability must be achieved by 2040. A reduced water supply, and uncertain future conditions due to climate change, will further challenge users in how they make decisions to comply with regulations.
