DESIGN OF PRESSURIZED IRRIGATION SYSTEM TO IMPROVE WATER USE EFFICIENCY IN CANAL COMMAND

Abstract

The limited existence and the misuse of the available water resources have put pressure on the judicious use of water for irrigation. Likewise, Awash River is under increasing pressure due to the increase in demand and excessive exploitation of the available resource. The problem is escalating since this river is the only source of fresh water in the basin. Therefore, modernization of an existing irrigation system is the need of hour so that the scarcity of water resources can be addressed effectively. It is felt that the Pressurized Irrigation System (PIS) is one of the best ways to deliver water to the field preferably when the resource is scarce, the topography is undulating and/or rugged and source of water is from ground. Furthermore, this system is quit resilient and is preferred one as compared to canal irrigation system, particularly when there are complex issues of land acquisition, etc. Though the most challenging problem is the financial doubts i.e. the fear of replacement works and energy cost, the design of cost effective network that satisfies hydraulic requirements in accordance with demand patterns is an equal important parameter. For this study, EPANET 2 software was used for hydraulic analysis of pipe network while the optimization of the pipe size was done by Labye’s Iterative Dis-continues Method (LIDM). Most of the data used were from secondary sources. We could save 900,482 m3yr−1 volume of water for this study area if the system is converted to PIS. This volume of water has the potential to develop additional 91.8ha land per year. After optimizing the pipe size which was gained from the EPANET output using the LIDM, it was reached to the point that we could save 697,763 ETB for the pipe cost. Key words: pressurized irrigation system, pipe network, EPANET, LIDM, water use efficiency, piezometric elevation head