Abstract:
Groundwater nitrate contamination and water level decline are common concern in Nebraska. Intensive use of agrochemicals is the major source of nitrate and atrazine in Nebraska groundwater. This study was conducted to determine the increase of groundwater wells in some areas and the effect of land use “agriculture practices” on nitrate and atrazine concentrations in Nebraska using GIS tools and applications. Dams and lakes location in Lancaster County in southeast Nebraska were mapped along with nitrate and atrazine concentration in each location. GIS maps of land use, groundwater layer thicknesses, water table contours, rivers, and railroads were prepared. For nitrate and atrazine concentrations, the study showed that the high concentrations were associated with areas of intense irrigated crops (mostly corn and soybean) production. These high concentrations are attributed to high application of fertilizers and pesticides. The study also indicated an increased number of wells especially in the eastern part of the state. The study result however indicated that the groundwater layer thicknesses were associated with spatial well distribution. Areas near the rivers and railroads also had high numbers of irrigated wells due to accessible maintenance operations and lower cost of transportation.
