Potential assessment of non-automatic and automatic modernization alternatives for the improvement of water distribution supplied by surface-water resources: A case study in Iran

Abstract

Water shortages have led farmers within irrigation districts to resort to groundwater resources. In this scenario, a decrease in those water losses due to improper operational management within the districts may halt the increasing trend of groundwater overexploitation. This study aims to examine the impact of improving operational management in irrigation districts both to provide reliable surface water distribution and to reduce groundwater demands therein. To this end, a set of operational alternatives were investigated, including nonstructural approaches, structural modification, and automatic control systems. The potential amount of the reduction in the groundwater demands can be measured under each of the alternative operations for the delivery of water to farmers. The study is conducted on the hydrodynamic model of an irrigation canal affected by 20–70 % inflow fluctuations, which occur due to water shortages at the head source. The results of the operational simulation indicate that appropriate management of the water delivery systems within non-structural alternatives can lead to a 2–13 % improvement in operational performance indicators in comparison with the structural modification. Accordingly, the application of non-structural approaches can potentially decrease the groundwater demand by 5.352 and 8.428 Million Cubic Metres (MCM) from deep tube-wells and 2.817 and 2.007 MCM from the semi-deep tube-wells over the period of one water year. However, when employing automatic control systems, operational services to the users undergo a 15–62 % enhancement such that groundwater demand drops by 11.561 and 20.39 MCM per year, respectively.