Linkages between land-use change and groundwater management foster long-term resilience of water supply in California

• Published in: Journal of hydrology. Regional studies 2022-04, Vol.40, p.101056, Article 101056
• Main Authors: Van Schmidt, Nathan D., Wilson, Tamara S., Langridge, Ruth
• Format: Article
• Language: English
• Subjects: Groundwater; Land use change; Overdraft; Socio-ecological system; Sustainable Groundwater Management Act; Water management
• ISSN: 2214-5818; 2214-5818
• DOI: 10.1016/j.ejrh.2022.101056

We created a 270-m coupled model of land-use and groundwater conditions, LUCAS-W[ater], for California’s Central Coast. This groundwater-dependent region is undergoing a dramatic reorganization of groundwater management under California’s 2014 Sustainable Groundwater Management Act (SGMA). Understanding land-use and land-cover change supports long-term sustainable water management. Anthropogenic water demand has depleted groundwater aquifers worldwide, while future water shortages will likely affect land-use change, creating system feedbacks. Our novel participatory approach fused changes in land-use and associated water use from county-scale data to local water agencies’ estimates of total sustainable supply, scaling up local hydro-geologic knowledge from heterogeneous aquifers and diverse management approaches to a regional level. We assessed five stakeholder-driven scenarios with the same historic rates of urban and agricultural land-use change, but different water and land-use management, analyzing how management strategies altered both the spatial pattern of development and subsequent water sustainability from 2001 to 2061. Transformative strategies using demand-side interventions that coupled water availability to land-use more effectively achieved long-term sustainability than adaptive strategies using supply-side interventions to increase water supplies. Limiting water withdrawals within SGMA regulated basins resulted in leakage of development into unregulated basins, increasing groundwater pumping there. Protecting ecosystems, farmlands, and recharge areas from development reduced leakage into undeveloped basins without negatively affecting water sustainability. [Display omitted] •Water demand caps can achieve groundwater sustainability under future development.•Enhancing water supplies was not effective at achieving long-term sustainability.•Caps caused leakage of development and pumping to unregulated groundwater basins.•Land-use management strategies (preserving habitats) prevented this leakage.