Harnessing the Corners of Pivot Irrigated Fields for Solar Energy, Groundwater, and Improved Farm Resiliency

One underexplored opportunity for dual-use solar energy development is enhancing water resources. In southwest Kansas farmers depend on pumping irrigation water from the depleting groundwater resources of the High Plains Aquifer. Current practices are becoming increasingly unsustainable as increased intensity and frequency of drought further accelerate water level declines. In center pivot fields, a circular irrigation footprint leaves unirrigated and often underutilized corners that account for approximately 18% of field area. Installing solar arrays in these corners can enhance the economic resilience of farms through both energy production and enhanced recharge of groundwater aquifers. We are designing and installing an experimental pair of arrays within a farm field near Garden City Kansas. This experiment will compare: 1) a conventional solar design for the region and 2) a design that will prioritize routing rainfall into the soil to provide groundwater recharge. Estimates indicate that in a typical year with 40 cm of precipitation the design could route 27 cm to recharge. If implemented to cover all four corners of a pivot irrigated field, this system could provide as much as 14% of the field's annual irrigation use, and help farmers achieve sustainable groundwater pumping goals. Since maximizing recharge may involve changes to system design that reduce energy production, we will compare the energy production and hydrologic impacts of each design to quantify the trade-offs in solar efficiency, groundwater recharge, and farm economics. Beyond the farm, the loss of energy generation necessary to maximize water collection will necessitate the development of a system through which groundwater recharge can be valued and incentivized. The prevalence of pivot irrigated fields across southwest Kansas provides a unique opportunity to integrate solar energy installations, and enhance water resources, without disrupting existing agricultural land use.