Methodology for flushing pressurised irrigation networks for fertigation and operation maintenance purposes

Pressurised irrigation networks with a certain degree of automation allow centralized fertigation and maintenance operations such as cleaning subunits and preventing the proliferation of invasive species such as zebra mussels. Until now, there is no methodology that guarantees the total cleaning of the network of a substance in the shortest possible time. In the same way, it does not exist to guarantee reaching all consumption points with a certain concentration of a substance, injecting the minimum possible amount. For that purpose, a general novel methodology has been developed that makes use of the network’s hydraulic model and parallel multi-objective genetic algorithms to flush the network of a certain substance or to get it to all consumption points in the shortest possible time and supplying a minimum volume. This method assumes that the available pressure at the source is always over a minimum value. The arrival times to the consumption points are minimized and the injected volume is reduced to the minimum of replacement, that is, the volume of the network pipes. The methodology applied to the study case allowed the entire network to be flushed in a minimum time of 2.46 h. On a normal irrigation day, without making any changes to the irrigation schedule the time to completely flush the network is 11.76 h. Furthermore, the injected volume differs greatly from the total volume of the pipes.