Livestock and Small-Scale Irrigation Scheme Interactions as a Key Source for Sedimentation during the Irrigation Season: Four Case Studies from South-West Shoa, Ethiopia

Hanan Tadele Dessalegn,Alex Bolding,Mekonen Ayana,Charlotte de Fraiture

doi:10.3390/su13105745

Abstract

Small-scale irrigation (SSI) development can play a major role in Ethiopia’s economic development, but sedimentation is a major threat to its sustainability. The focus of the dominant discourse around the sedimentation of SSI schemes lies in upstream catchment protection during the rainy season, neglecting both protection against erosion through overland flow along the margins of the canal network and sedimentation caused by livestock disturbances. Remedies against the latter causes of sedimentation during the irrigation season have been ineffective due to erroneous assumptions regarding its cause. This study aimed to identify the sources and extent of sedimentation in SSI schemes. The accumulated sediment in the canal pre-irrigation season was measured from four SSI schemes and suspended sediment samples during irrigation season were collected from one SSI scheme. The accumulated sediment in the canal pre-irrigation season was measured from four SSI and suspended sediment samples during irrigation season were collected from one SSI scheme. The extent of sedimentation in the canals during the pre-irrigation season in relation to canal capacity was 100% of lined and unlined canals in abandoned, 68% in a lined, and 84% unlined canals in heavily sedimented and 38% in a lined and 46% of unlined canals lightly sedimented schemes. Livestock interactions with the SSI schemes were found to be the major sediment source before and during the irrigation, hence, attention should be given to integrating livestock as a part of the system.

Highlights

Irrigation development plays a major role in Ethiopia’s economic development program [1]
Information of Each Study Scheme In Ethiopia, small-scale irrigation schemes are divided into different categories based on the establishment, management, and nature of the structure
We interviewed 75 persons in total: 18 women and 45 men farmers spread across the head, tail, and middle-reaches of the four schemes, including Water User Association (WUA) and Livestock Farmers Association (LFA) committee members

Summary

Introduction

Irrigation development plays a major role in Ethiopia’s economic development program [1]. In Ethiopia, small-scale irrigation schemes are divided into different categories based on the establishment, management, and nature of the structure. Traditional irrigation schemes usually use temporary diversion arrangements or barriers made from local material which need annual maintenance. The canals are usually earthen, and the schemes are managed by the community. Modern schemes are irrigation systems with more permanent diversion weirs made from concrete that do not require annual re-construction. They are mostly community-managed, and the primary and secondary channels are made of concrete. Modernized schemes are traditional schemes that were upgraded after some time with more permanent diversion and concrete canals [25]

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Conclusion