Application of the simulated annealing method to agricultural water resource management

This work presents a model based on the on-farm irrigation scheduling and t he simulated annealing (SA) optimization method for agricultural water reso urce management. The proposed model is applied to an irrigation project loc ated in Delta, Utah of 394.6 ha area for optimizing economic profits, simul ating the water demand and crop yields and estimating the related crop area percentages with specified water supply and planted area constraints. The application of SA to irrigated project planning in this study can be di vided into nine steps: (1) to receive the output from the on-farm irrigatio n scheduling module; (2) to enter three simulated annealing parameters; (3) to define the design 'chromosome' representing the problem; (4) to generat e the random initial design 'chromosome'; (5) to decode the design 'chromos ome' into a real number; (6) to apply constraints; (7) to apply an objectiv e function and a fitness value; (8) to implement the annealing schedule by the Boltzmann probability; and (9) to set the 'cooling rate' and criterion for termination. The irrigation water requirements from the on-farm irrigation scheduling mo dule are: (1) 1067.9, 441.7, and 471.8 mm for alfalfa, barley and maize, re spectively, in one unit command area; and (2) 1039.5, 531.4, 490.9, and 539 .4 mm for alfalfa, barley, maize and wheat, respectively, in the other unit command area. The simulation results demonstrate that the most appropriate parameters of SA for this study are as follows: (1) initial simulation 'te mperature' of 1000; (2) number of moves equal to 90; and (3) 'cooling rate' of 0.95. (C) 2001 Silsoe Research Institute.