Developing an Optimal Design Model of Furrow Irrigation Based on the Minimum Cost and Maximum Irrigation Efficiency

The main objective of the furrow irrigation is appropriate selection of planning and managerial variables. These variables are: the furrow length, flow rate to the furrow and cut-off time. These variables are computed through optimization based on minimizing the total irrigation cost and maximizing the application efficiency of irrigation. The objective function has been formed based on costs of the water, worker and head ditch and furrow digging. Therefore, in the objective function, an equation should be considered for computing the water advance period in a clear and precise manner. Since none of the exact methods used for planning furrow irrigation like zero inertia, compute the advance time explicitly, thus in this research the Valiatzas equation has been used which has been deduced from the results of the zero inertia model. In the objective function, in addition to the planning variables, soil characteristics, furrow and net irrigation requirement have been included. Therefore, the design variables and irrigation efficiency can be computed for each type of soil and specific plant. A sample of this design has been presented in this paper.