Layout structure of multi-quality irrigation networks: I—introduction and layout types

Abstract

The affect of network structure on the performance of water supply systems of diverse water quality sources was assessed, using analytic methods. The analysis is presented in a series of 3 papers in which this paper is the first of the series. Five types of network structures were analyzed: i) single networks; ii) separate sub-networks; iii) multiple networks; iv) dilution networks; and v) combined dilution-separate networks. The properties of each network type were evaluated using the Q-C “Feasibility domain” (QCFD) concept, where discharge (Q) and concentration (C) are the major design parameters. The dilution network type was found most flexible and the single and separate network types were most rigid. The multiple network type provides certain flexibility, however it was exceptionally expensive. The improved network, which combined the advantages of the separate sub-networks with the dilution network was proposed and as an optimal design. The planning of such systems commenced with an initial analysis at the sources-consumers’ level without network facilities. The second stage required analysis of the various structures of the network layout. Ultimately, a layout was assumed and the effect of flow directions in that network was assessed for installation of back flow preventing devices, and improving the control of water quality. A rural region in southern Israel of 6 sources, 5 villages, and 8 fields was chosen. The 5 types of networks were planned for this region. The effect of network structure on the performance of these networks was analyzed and discussed.