Layout structure of multi-quality irrigation networks: II—flexibility, separability and rigidity of networks

Abstract

Three parameters were introduced here, in the second paper of the series, to evaluate layout structure of multi-quality water supply networks for irrigation. The first parameter was flexibility, which assesses the capability for a flexible supply of variable water quality values which can be obtained by dilution inside the network facilities. The second was separability which expresses the capability of the network to be divided into separate isolated sub-networks, each carrying a different water quality. The third was rigidity, which expresses a rigid allocation of one to one source–consumer connections. Five types of network layout which were presented in Sinai (2011) were evaluated here, using these three parameters. The flexibility of a network was given special attention with the example of parallel and serial connection of fields to sources. A real example of a proposed network in the Hazeva region in Israel was analyzed. All feasible flow patterns (FFPs) were computed. The location of mixing and dilution junctions and computation of the QC feasibility domains were found and computed for every junction and consumer. Relative ranges of discharges and concentrations were conducted for all the FFPs found. However, no single optimal FFP with maximal flexibility was found. Therefore the FFPs were arranged in operational groups for possible sequential operation according to irrigation schedules.