Dr. Thomas Harter, the Robert M. Hagan Endowed Chair for Water Management and Policy, Department of Land, Air and Water Resources, University of California, Davis, will deliver a Water Institute Lecture: Future of Groundwater Management in California.
Abstract
Groundwater resources across California’s agricultural regions have been more stressed during the most recent drought than at any other time in history. Lower groundwater levels have significantly increased pumping costs, and increased the need for constructing deeper wells, where wells were not sufficiently deep to keep up with falling water levels. Record low water levels have drastically increased the rate of land subsidence at a large scale, in the Central Valley, coastal basins, and southern California, but also exacerbated seawater intrusion where pumping occurs in aquifers near the coast. As wells pump deeper, water quality is sometimes compromised due to saline water or naturally occurring contaminants. Agricultural regions are also impacted by significant groundwater quality degradation from nitrate and salt pollution. Highly intensive specialty crop farming and animal farming, especially dairies, lead the contribution of groundwater nitrate and salts.
Groundwater is a critical resource for California water management, storing water from the rainy season for dry and hot summers, and from wet years for droughts. Eight of ten Californians rely on groundwater for drinking water. Managing groundwater quantity in the agricultural landscape is intricately linked to protecting groundwater quality and vice versa. Groundwater management also cannot be done without managing surface water resources. The future of groundwater use, protection, and management in California’s agricultural landscape will be an increasingly integrated approach to co-manage water quality and quantity of surface water and groundwater. Land use planners must also increasingly be involved in and informed by water planning and assessment activities. New regulations for groundwater sustainability and groundwater quality protection have emphasized the engagement of landowners and local stakeholders in the planning and implementation of new regulations, providing farmers with opportunities for engagement, dialogue, and education, and challenging scientists to better understand the impact of agriculture on groundwater, to identify potential monitoring tools, and to collaborate with agricultural scientists on innovative solutions for agricultural source control.