Application of a genetic algorithm for water allocation in an irrigation system1

Irrigation is the largest use of fresh water globally, and improved management of water within irrigation systems is essential if scarce resources are to be used to their maximum benefit and used in an equitable manner. The management of water allocation in large irrigation systems is important, as even a small improvement in operation may lead to significant benefits. An optimisation approach based on genetic algorithms (GAs) is described for real time allocation of irrigation water supplies. Appropriate objective functions for the water allocation problem have been derived previously and solved using quadratic programming (QP). This paper describes work on the development of a GA for the water allocation problem. The GA approach is very flexible, and is easily set up for a wide range of linear and non‐linear objective functions. This paper presents the development of a GA for the irrigation water allocation problem and investigates the sensitivity of the approach to different formulations. The GA approach can provide solutions that are similar to those produced by QP. It is, however, sensitive to string length, and has difficulty in meeting closed nodal water balance constraints. It is concluded that the GA approach offers no advantage over the QP for the water allocation problem.