Evaluating the Hydraulic, Managerial, Socio-Economic and Environmental Performance of Ahero Irrigation Scheme

Abstract

Many of Kenya’s public irrigation schemes are performing below potential resulting in low yields suggesting the need for irrigation performance assessment of the schemes. The hydraulic, management, environmental and socio-economic factors are crucial in the performance evaluation of an irrigation scheme. The aim of this study was to evaluate the hydraulic, managerial, socio-economic and environmental performance of Ahero Irrigation Scheme (AIS) in Kenya. This information will be crucial when doing performance improvement of the scheme. To evaluate the technical performance, the indicators used were: adequacy, equity, efficiency and dependability of irrigation water supply. Adequacy was calculated as the ratio of the amount of water delivered to the amount of water required by the crops. Efficiency was calculated as the amount of water delivered to farms to the amount of water supplied from the pump station. Dependability was measured as the variance in the temporal water supply. Equity was measured as variance in the spatial water supply. The indicators used under the managerial parameter include: effectiveness of infrastructure, land renovation ratio and training to farmers. To determine the effectiveness of infrastructure, the number of functional structures were counted and a ratio of functional to total number of structures calculated. Similarly, land renovation was calculated as a ratio of area under irrigation to the total command area of the irrigation scheme. Questionnaires were used to gather feedback on level of extension services if any, advanced to farmers in order to determine the training level. For the socio-economic parameter, the indicators were the credit ratio and farmer incomes. Credit ratio was calculated as ratio of credit required by farmers to the credit given. For the environmental performance evaluation, the indicator used was the drainage ratio calculated as a ratio of the drained water to the incoming water. On the technical parameter, the canal’s conveyance efficiency was found as 60% which was rated as poor; adequacy in the upper, mid and lower streams of the scheme was 0.99 rated as very good, 0.82 rated as good and 0.74 rated as poor respectively. Equity was 0.57 corresponding to a rating of poor; the coefficient of variance for dependability for the 2020 April-July season was 5.3 rated as good based on standard classifications, while for the whole year, dependability was 16.23 and rated poor. The water distribution and utilization in the scheme was inefficient as per the technical performance findings. On the managerial parameter, effectiveness of infrastructure was found to be 89% while the irrigation ratio was found as 62%. It was also found that training to farmers was not undertaken regu1larly, implying farmers were not well-abreast with effective farming operations. On the socio-economic parameter, the credit ratio was 0.5-0.75, meaning farmers could not access their full loan requirements compromising on their farming operations and hence production. Credit was given to farmers based on their capacity to pay back. On the environmental parameter, the drainage ratio was found as 33% and hence the ponding of irrigation water in the scheme due to poor drainage. Under limited resource conditions and based on the overall AHP analysis, the technical parameter (51%) should be given more priority followed by the socio-economic (32%), management (11%) and the environmental parameters (6%) respectively while prioritizing the most important parameters to be fixed. The study recommends lining of the main canal to enhance the hydraulic performance coupled with prompt repairs of damaged hydraulic structures. The study also recommends further research to utilizing more hydraulic performance indicators such as the groundwater ratio for better understanding of the scheme performance situation.