Analysis of Adequacy, Dependability, and Equity of Surface Water Allocation by a Decentralized Automatic Control System under Water Scarcity Conditions: A Case Study of the Nekouabad Irrigation Network in Isfahan

Document Type : Research Paper

Authors

1 Dept. of Water Engineering, Faculty of Agricultural Technology (Aburaihan), University College of Agriculture & Natural Resources, University of Tehran, Tehran, Iran

2 Water Engineering Department, Faculty of Agricultural Technology, University College of Agriculture & Natural Resources, University of Tehran

10.22059/jwim.2024.377591.1165

Abstract

This research aimed at introducing automatic control systems for surface water irrigation networks as an effective approach to reduce water losses in the agricultural sector. The technical aspects of developing these systems in modern irrigation network modernization projects were considered. Extensive field operations were conducted to collect existing data and perform field measurements in the surface water sector (open channel systems and related hydraulic structures). Subsequently, simulation of the surface water distribution process under normal and drought scenarios was carried out to enable spatio-temporal analysis and evaluation of surface water distribution among tertiary agricultural units. In this context, modeling of intelligent surface water distribution systems using the development of decentralized PI automatic control systems was also performed to investigate the impact of surface water distribution system modernization. The simulation results showed that the improvement in the efficiency index of surface water distribution in the upstream, midstream, and downstream reservoirs of the network for the decentralized PI automatic control system was in the range of 10-7%, 5-15%, and 15-4% under different water scarcity scenarios. Similarly, the improvement in the stability index of surface water distribution was 25-4%, 41-9%, and 42-9%, respectively. The improvement in the equity index of surface water distribution after self-calibration was in the range of 13-3% under different scenarios. The results indicate that under the normal scenario, with the use of the PI automatic control system, the water distribution in all reservoirs of the upstream and midstream reservoirs was in a satisfactory state. The results of the spatio-temporal analysis carried out in this research provided a clear pattern of the inefficiency of the irrigation management system in surface water distribution under water scarcity scenarios and identified the maps of vulnerable areas of the network. It is noteworthy that the methodology developed in this research can be implemented in about 2 million hectares of irrigated lands in the country, which are covered by 120 irrigation and drainage networks.

Keywords

Main Subjects