RISK VERSUS ECONOMIC RETURN IN MANAGING GROUNDWATER NITRATE CONTAMINATION

A nitrate transport model was developed to project the impact of a sub stantial buildup of nitrate in the groundwater in the eastern Sandhill s region of Nebraska. Predicted nitrate levels were evaluated using a Multi-Criteria Decision Making technique. Two criteria were used to de termine optimum farm management practices: economic return to the irri gators and risk to domestic water users. The optimum farm management p ractice consisted of an above average irrigation rate and a below aver age nitrogen fertilizer rate. The low fertilization rate had one of th e lowest risks of excessive ground water nitrate levels, while the hig h irrigation rate maximized the economic return. Therefore, this pract ice was optimal because it was the best compromise between minimum ris k and maximum economic return. The risk of excessive groundwater nitra te for the optimum practice was 51 percent and for the other seven pra ctices simulated ranged up to 54 percent.