Water allocation model for limited irrigation

For irrigation managers with limited water resources, irrigation management decisions begin well before the irrigation season. Irrigation managers with limited water supplies from, restricted well capacities or water allocations need to anticipate crop selections, plan for crop rotations, and project water deliveries to each crop. A water allocation model [Crop Water Allocator (CWA) available at www.oznet.ksu.edu/mil] has been built to evaluate growing-season water allocations among two to six crops over five possible divisions of land area. Users input crop pricing, production costs, irrigation costs, and maximum crop yields. The program iterates all possible combinations of the water allocation by 10% increments over all possible crop combinations and a chosen land division. Net economic return to land, labor, and irrigation equipment is calculated for each crop mix/water allocation/land division combination. Net returns are ranked, and several of the highest are presented to the user for evaluation. The influence of one variable input on another, such as water allocation, commodity prices, crop yields, annual rainfall, irrigation system efficiency, and irrigation operating costs on net return can be evaluated through multiple executions of the model.