Analysis of Conveyance Losses from Tertiary Irrigation Network

Naeem Shah Bukhari Syed,Rajesh Kumar Soothar,Zhao Shuqi,Muhammad Munir Babar

doi:10.28991/cej-2021-03091756

Abstract

Irrigation canals are generally made through porous soil formations, since the soil is loose porous media – a huge amount of canal water is lost to conveyance losses. The situation becomes direr when these losses result in non-beneficial losses. The Sindh province of Pakistan has more than 70% saline groundwater, conveyance losses to such areas in the province not only become unusable but also creates water management problems. Perhaps the only cost-effective way to address these losses is canal lining. The present study was conducted in the command area of Belharo distributary, Sindh, Pakistan with an aim to determine the extent of losses from the tertiary irrigated network as these water channels are less considered in the literature with regards of conveyance losses. Using water balance method, conveyance efficiency and conveyance losses at 30% lined and 50 and 75% unlined length of the watercourses was observed. The results revealed that the tertiary irrigation channels face an average of 43% conveyance losses and major proportion of these losses is lost to non-beneficial losses from the study area. The study further suggests 75% lining of watercourses in order to minimize non-beneficial losses. This study also infers that with the use of geo-membrane lining, sizeable amount of fresh water can be saved. Doi: 10.28991/cej-2021-03091756 Full Text: PDF

Highlights

Earthen irrigation channels are usually made through loose soil formations, since irrigation channels convey water to farmers’ fields over large distances; in the process a significant amount of irrigation water is lost [1, 2]
The results revealed that lining improves conveyance efficiency of water channels on an average of about 97 percent at 30% lined length
Similar results have been reported by Kilic & Tuylu (2010) [23] from Ahmetli regulator irrigation system, lower Gediz basin, Turkey where they found about 98% conveyance efficiency from lined watercourses while Mangrio et al (2015) [15] concluded that lining improved the conveyance efficiency to about 97% from the tertiary irrigation network off-taking from Mureed minor in Jamrao canal command of Sindh, Pakistan and Eshetu & Alamirew (2018) [24] reported around 94% conveyance efficiency from the lined field channels of Tendaho sugar estate, Ethiopia

Summary

Introduction

Earthen irrigation channels are usually made through loose soil formations, since irrigation channels convey water to farmers’ fields over large distances; in the process a significant amount of irrigation water is lost [1, 2] Such losses are technically termed as conveyance or operational losses and are mainly caused due to seepage into soil or evaporation. Ghumman et al (2011) [10] reported that the excessive conveyance losses degrade agricultural lands due to waterlogging and salinization, resulting in ultimate yield losses for majority of crops. They reported that 38 and 14% of the total land area in Pakistan is characterized by waterlogging and salinity, respectively. Groundwater becomes saline due to high conveyance losses or where the groundwater aquifers are already saline, conveyance losses to such aquifers becomes unusable in the shape of return flows or downstream usage [13]

Methods

Results

Conclusion