Date of this Version
D. T. Riley, Using Regression Analysis to Determine Land Cover Impacts on Groundwater Levels in the High Plains, MS Thesis, Department of Agricultural Economics, University of Nebraska–Lincoln, 2018. Accessed [mm/dd/yyyy] from http://digitalcommons.unl.edu/agecondiss/
Many parts of the High Plains region are facing declining aquifer levels, which threatens the long-term viability of irrigated agriculture. Furthermore, some areas of the High Plains region, like the Republican River Basin in Nebraska, need to keep groundwater levels high enough in the short-term to ensure that hydrologically connected rivers have enough streamflow to fulfill surface water obligations, such as Nebraska's interstate river compact with Colorado and Kansas. To better manage groundwater, it is important to understand the unintended effects of policies that may not be aimed at groundwater conservation, such as the USDA- Conservation Reserve Program (USDA-CRP). The CRP pays farmers to take cropland out of production and put it into conservation covers, mainly grassland. Environmental benefits include reduced soil erosion, improved surface water quality, and increased wildlife habitat. But, the changes in land cover due to CRP enrollment could also impact the infiltration of precipitation through the soil, thus changing groundwater recharge. The paper estimates the potential effect of CRP on groundwater levels using data from Ogallala Aquifer region of Kansas and the Republican River Basin portion of Nebraska. The analysis relates disaggregated aquifer level data with spatial land cover data, weather, soil, and groundwater extraction data. Grassland land cover is used as a proxy for grassland put in by CRP. Findings suggest that grassland leads to a lower yearly recharge rate than common crop land covers in the Republican River Basin of Nebraska. Recharge in the Ogallala Aquifer region of Kansas seems too small to have a detectable impact though. These results imply that in addition to other environmental benefits, policymakers need to pay attention to the impact of CRP enrollment on regional aquifer conditions in regions where groundwater levels are a concern but can expect recharge to take place.
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