Presentations 2016

Economic Analysis of Groundwater Banking on Agricultural Lands in California

University of California, Davis

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Since 1865 California has practiced underground water storage through artificial recharge; however, in many parts of the state, these efforts have been insufficient to meet growing water demands, particularly for irrigated agriculture. During dry periods, vast agricultural areas depend upon groundwater for irrigation. In these areas, groundwater banking (GB) can be an essential strategy for water management operations. GB is the practice of diverting surface water to percolation or injection sites for aquifer storage and later recovery. One variation of GB is agricultural GB -- the use of agricultural lands for GB (Ag-GB). The economic implications of Ag-GB are an unknown component of GB necessary to inform water agencies and farmers interested in implementing the practice. Therefore, this study proposes a conceptual model for determining the economic feasibility of Ag-GB at the irrigation district level. The Orland-Artois Water District (OAWD) in Glenn County is considered as the case study, and alfalfa as the test crop due to its tolerance to flooding and low use of pesticides and fertilizers (potential sources of aquifer contamination). The proposed model consists of four components: (1) an agricultural water demand calculator, which calculates agricultural water demands based on historic land use, monthly precipitation, and crop coefficient values, (2) a one-bucket aquifer mass balance model that quantifies inflows and outflows to the simplified aquifer, (3) an agronomic model, which estimates costs and benefits of Ag-GB in terms of energy savings from pumping and crop production, and (4) an economic feasibility output, in which costs and benefits are evaluated to determine economic feasibility.