Environmental Impacts Investigation of Irrigation Projects: Case Study of Kanyonyomba Rice Perimeter in Rwanda

Abstract

Irrigation is an agricultural practice adopted in Rwanda to fight against poverty by increasing agricultural production as a big sector which occupies a central place in the economy of the country. Once irrigation project is made without taking into account the environmental impacts that may occur, it may fail before the design period or may persist with the excessive generated negative impacts exceeding the targeted objectives. The aim of this study was to investigate environmental impacts of an already implemented irrigation project in Kanyonyomba swamp located in Gatsibo District of Eastern Province of Rwanda in order to quantify the benefits and to increase agricultural production by mitigating negative impacts generated by this project. The Kanyonyomba earth dam has been constructed on Kanyonyomba River in Gatsibo District with a length, a spillway crest width and a reservoir height of 210 m, 4 m and 8.5 m respectively. The site observations on land, the interviews analysis and water and soil laboratory tests were conducted to assess various environmental impacts. The analysis of the results reveals the presence of positive impacts including increased agricultural space and agricultural production through the introduction of rice cultivation in this medium. However, this project has led to multiple adverse effects in the hosting environment impacts that need to be mitigated including the increased incidence of diseases in the surrounding population and accidents resulting from an increased exposure of people to the dam reservoir. Moderation of soil acidity, the use of the dam reservoir as a water supply source, the provision of boots and gloves to protect farmers from being contaminated by water living microorganisms and the development of impacts monitoring plan are among the proposed measures in order to mitigate these environmental impacts.