Simple Method for Identification of Border Infiltration and Roughness Characteristics

Abstract

Roughness and infiltration parameters in border irrigation are evaluated with reasonable accuracy and simplicity by iterative analysis of advance‐trajectory data and surface‐depth measurements at a station at or near the inlet end of a border. Approximate estimates of the parameters obtained by simple algebraic equations are successively corrected with the aid of an exact solution (zero‐inertia simulation). Numerical experiments are performed to gage the limitations of the method, particularly as regards necessary uniqueness. Results indicate that nonuniqueness is not a problem for the present method. Rate of convergence of the method is significantly greater than that of other methods, based on gradient optimization techniques. Thus, even expensive‐to‐run, but highly accurate, surface irrigation models (i.e. full‐dynamic models) can be used to solve the direct physical problem. The method is also applied to a field border‐irrigation test.