Integrating climate change into groundwater sustainability planning: challenges and opportunities for climate informed groundwater management in California

Abstract:

Groundwater is an important resource globally, particularly for irrigation. However this resource is critically overdrafted in many agricultural basins across the world, limiting access for both domestic and agricultural demands. Climate change is likely to further negatively impact groundwater supplies via a number of pathways, including: changing the volume and timing of water availability, degrading water quality, threatening existing water infrastructure with more extreme events and changing demand via increasing temperature and evapotranspiration. Sound incorporation of climate change into groundwater sustainability planning is an important step towards climate resilient groundwater management actions and decisions to achieve long-term groundwater sustainability. California’s 2014 Sustainable Groundwater Management Act (SGMA) represents a unique opportunity to examine the range of strategies used to incorporate climate change in groundwater planning in response to the regulatory mandate. In this study, we use SGMA as a natural umbrella experiment to evaluate the effectiveness of a regulatory mandate as a policy tool to integrate climate change into groundwater planning. We also examine the contextual factors and implementation pathways that enable sound integration. We analyze 46 Groundwater Sustainability Plans (Plans) released in January 2020 by California’s 21 critically overdrafted groundwater basins focusing on six key criteria for climate change integration: internal coherence, climate-relevant goals, physical conditions, uncertainty, risk and updating climate change knowledge. This research provides some critical insights into challenges and opportunities for achieving short-term and long-term groundwater sustainability under climate change using policy vehicles and regulatory tools.