Water Resources Research Act Program

Details for Project ID 2019CA025B

Assessment of water storage for management of California’s oak woodlands

Institute: California
Year Established: 2019 Start Date: 2019-06-01 End Date: 2020-05-31
Total Federal Funds: $15,000 Total Non-Federal Funds: $44,600

Principal Investigators: Margaret Zimmer

Abstract: How ecosystems route water governs drought resilience, groundwater recharge, and landslide, flood, and wildfire hazards. The physical, biological, and climatic processes that determine water partitioning in the diverse natural ecosystems of California are still poorly understood–but critically important for proper water resource management. We will apply a suite of novel geophysical, hydrological, and isotopic approaches toward a comprehensive understanding of water storage and movement controls within a semi-arid coastal watershed. At the University of California’s Blue Oak Ranch Reserve, we will quantify the above and belowground physical and biological architecture and the resulting hydrologic flowpaths in this representative ecosystem, where oaks commonly dominate shorter and steeper north-facing slopes and grasslands cover longer and lower gradient south-facing slopes. This natural, aspect-dependent contrast permits exploration of the biophysical controls on water distribution in landscapes with uniform rainfall and underlying lithology. Across a range of hillslopes, we will investigate the subsurface depth from which oak trees access water and determine if the depth of plant-water uptake changes seasonally or in response to groundwater fluctuations. Further, these warmer, drier south-facing slopes may provide a glimpse into future environmental conditions. Our goal is to understand possible mechanisms for oak resilience to future shifts in temperature and drought conditions. Thus, we will install permanent sensors that can provide management relevant data into the future. We will share our findings with water managers and oak woodland conservation groups near the BORR as well as statewide with key agencies associated with the 2014 Sustainable Groundwater Management Act.