Field-Scale Sprinkler Irrigation System Hydraulic Model. II: Hydraulic Simulation

Abstract

This paper describes a mathematical model for the hydraulic characterization of a field-scale solid set sprinkler irrigation system with a double-line lateral layout configuration. Formulation of the basic hydraulic equations along the mainline and laterals is based on manifold hydraulics. Lateral hydraulics remains the same as that described in a previously published paper, for systems with single-line laterals. A description of the mainline hydraulics of systems with a double-line lateral layout configuration, which requires the formulation and iterative solution of a system of nonlinear equations, is presented here. The hydraulic characterization functionality of the model, described in a previously published paper, serves as an interface for coupling the numerical solutions of the lateral and mainline hydraulic equations. In addition, this paper presents a description of the simulation functionality of the sprinkler hydraulic model and a related numerical algorithm, which is based on one-dimensional optimization. A comparison of model output with field data suggests that model performance is satisfactory. Example problems, consisting of field-scale solid set sprinkler systems with single-line and double-line laterals, are used to highlight the practical application of the hydraulic model.