Implications of the water-energy-food nexus on coastal groundwater management, Pajaro Valley, CA

Abstract

In the Pajaro Valley in central California USA, intensive groundwater use for agricultural development has led to a 12,000 acre-foot per year groundwater overdraft and seawater intrusion since the 1950s. Consequently, the Pajaro Valley is considered a high priority basin under California's new (2014) Sustainable Groundwater Management Act (SGMA). Groundwater extractions for agriculture can come with significant energy costs; therefore, the Water-Energy-Food (WEF) Nexus theoretical concepts can provide additional information to support evaluation of SGMA requirements and the sustainable use of natural resources. In this study, I explore the implications of applying a WEF Nexus approach to coastal groundwater management and policy in the Pajaro Valley in the context of SGMA regulations. Using results from a regional hydrologic model of the Pajaro Valley, I quantify relationships and linkages (i.e., synergies, alterations, and trade-offs) within the water-forfood and energy-for-water Nexus of the Pajaro Valley. I also explore how these relationships respond to temporal trends in cropping patterns and irrigation demand. I present results that illustrate how understanding the Nexus relationships surrounding water use and availability, energy consumption for groundwater pumping, and food production can provide stakeholders with useful guidelines for optimal farming practices to mitigate seawater intrusion and other trade-offs associated with intensive groundwater use. Findings presented here have important implications for resource managers and policy makers toward developing sustainable groundwater management plans in coastal aquifers.