- 1Institute of Environment and Sustainability, University of California Los Angeles, USA
- 2Department of Earth and Planetary Sciences, University of California, Santa Cruz, California, USA
- 3Hydrologic Sciences Graduate Group, University of California, Davis, California, USA
- 4Department of Geophysics, Stanford University, California, USA
- 5Hydrologic Sciences Graduate Group, University of California, Davis, California, USA
- 6Hydrologic Sciences Graduate Group, University of California, Davis, California, USA
- 7Gund Institute for Environment, University of Vermont, Vermont, USA
- 8Hydrologic Sciences Graduate Group, University of California, Davis, California, USA
- 9University of California, Davis School of Law, California, USA
- 10University of Oregon School of Law, Oregon, USA
- 11Department of Land, Air and Water Resources, University of California, Davis, California, USA
- 12Department of Land, Air and Water Resources, University of California, Davis, California, USA
- 13Center for Watershed Sciences, University of California, Davis, USA
- 14Department of Earth and Planetary Sciences, University of California, Davis, California, USA
Sustainable groundwater management is critical in semi-arid regions, where competing demands from agricultural, urban, and industrial sectors strain water resources. California and Catalonia share a Mediterranean climate, where the peak growing season coincides with the driest months, necessitating significant reliance on stored water for irrigating agriculture. Here, we examine the science-policy interface in groundwater management by comparing Catalonia, Spain, and California's Central Valley—regions possessing similar climatic pressures but having developed distinct regulatory frameworks under differing hydrogeological contexts.
California's Central Valley is characterized by a vast, deep sedimentary aquifer system that supports the largest agricultural economy in the United States. However, over-extraction has led to domestic and agricultural wells running dry, severe land subsidence, and widespread nitrate contamination. In contrast, Catalonia's aquifers are generally smaller, shallower, and are more susceptible to saltwater intrusion from the ocean.
In 2014, California passed the Sustainable Groundwater Management Act (SGMA), representing a shift towards regulated groundwater use. However, the state’s complex water rights system—featuring separate allocation frameworks for groundwater and surface water—combined with the immense scale of the Central Valley Aquifer system, complicates the effective implementation of SGMA and its goal of sustainable groundwater management. Conversely, Catalonia, guided by the EU Water Framework Directive of 2000, has adopted an integrated approach to groundwater and surface water management within a unified framework that emphasizes public supply and sustainability.
We analyze the contrasting approaches of these two regions to explore what each can learn from the other’s management strategies. For California, Catalonia highlights the importance of treating groundwater and surface water as a single, interconnected resource within a unified regulatory framework. This demonstrates how conjunctive water regulation can improve long-term resource sustainability. Conversely, California’s extensive monitoring networks, basin characterization programs, and advancements in data collection offer valuable tools that could enhance Catalonia’s water management efforts. By focusing on these lessons, we aim to underscore how shared insights can inform more effective water governance in distinct hydrogeological and regulatory contexts.
This comparative analysis highlights the critical role of understanding the hydrogeological context in shaping blue diplomacy policies. It underscores the importance of interdisciplinary approaches, such as leveraging diplomatic tools and scientific expertise to address water security challenges and build resilience to climate extremes in semi-arid regions globally.
How to cite: Gomez-Cervantes, A., Yan, E., Scantlebury, L., Prentice, R., Ondris, K., Magee, B., van der Heijden, R., Grobowsky, K., Chavez, A., Archer, A., Dahlke, H., Harter, T., Yarnell, S., and Pinter, N.: Shared Challenges, Divergent Solutions: Groundwater Management in California and Catalonia, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-14284, https://doi.org/10.5194/egusphere-egu25-14284, 2025.
