ABSTRACT
A computer nonlinear optimization model was developed to interact upon a kinematic-wave hydraulic model to obtain the Kostiakov-Lewis parameters from measured advance data (furrow irrigation inverse problem). This model is part of a computer program, named SIRTOM (Surface Irrigation Real-Time Optimization Model), developed by Azevedo (1992) for solving the inverse problem. The model was tested for different field conditions. The analysis showed that even in the presence of narrow and steep valleys formed by local minima, the optimization model was able to exit these valleys and reach the lower regions, where was the global minimum. Also, the model exhibited a rational convergence path in searching for reliable solutions to the inverse problem, and showed to have a mathematical ability to identify and correct inaccuracies in field measured infiltration coefficients. Besides that, the model provided reliable solutions early enough during the advance phase, which is fundamental to the SIRTOM program for making a real-time diagnosis and control of the irrigation event hydraulic conditions, in order to improve the irrigation system performance.
Key words:
infiltration; advance; performance; irrigation management