New methods for the calculation of the probability of operation of each outlet in on- demand irrigation networks

Two new methodologies for the calculation of the probability p of operation of each outlet in on-demand irrigation networks, are developed in this work. The first one was based on the investigation of the factors: irrigation interval and time of irrigation, which co-modulate the probability p under real network operating conditions. It computes p as the weighted arithmetic mean of the values of probability with weights its relative frequencies of appearance after classifying the different irrigation intervals. This methodology is proposed for the calculation of p, especially at the project design stage, but also for the creation of databases as well as the second one. The comparison with Clément’s methodology, with the experimental data from the triennial survey on an irrigation network of Yiannitsa former lake’s networks, showed that the new method can approach satisfactory well the reality. Contrary, the results of Clément’s methodology, were far removed from reality, because the hypothesis on which it is based, that each day during the peak period is an equally likely irrigation day for each user, who operates independently from the others in a random manner, doesn’t get confirmed (as expected in irrigation practices). The second method is based on the time between two consecutive demands, which is also a result of the empirical way of managing irrigation water at irrigation unit level, and it calculates the probability by the mean of this time. This methodology for the calculation of the probability p in irrigation networks operating on-demand, during the peak irrigation period, is proposed only for the creation of databases in a simple and economical way.