IRRIGATION DECISION-MAKING AND GROUNDWATER USE OUTCOMES IN WESTERN KANSAS

Groundwater levels across parts of western Kansas have been declining at unsustainable rates due to agricultural irrigation use and subsequent groundwater pumping. Despite management strategies designed to decrease total groundwater use from the underlying aquifer (e.g., efficient irrigation technology), declines in groundwater levels are still observed throughout the region. This study seeks to statistically evaluate the impact of physical and socio-political factors to identify the predominant drivers to irrigation water use across western Kansas. A boosted regression tree analysis is used to describe the influence of various drivers such as governing policies, market prices, or soil characteristics on total irrigation pumping across both space and time. By targeting the combinations of factors that statistically lead to the greatest volumes of groundwater pumping, robust management strategies can be developed to achieve conservation goals adopted in the region. This statistical approach can be replicated for other large-scale studies across the country, particularly in regions seeking to better understand irrigation use in a changing agricultural landscape.