Rate of Sediment Yield in the Conveyance Canals of Kano River Irrigation Project (Phase I) North-Western Nigeria

Abstract

This study examined the rate of sedimentation in the conveyance canals of Kano River Irrigation Project (Phase I). Five canals were sampled from the total number of canals using systematic sampling technique. The base lines of the canals were taken to be the transect line, and all the samples were taken with reference to the transect line using simple random sampling. The method adopted was a combination of volumetric analysis and filtration method for field and laboratory work respectively. Variables investigated include canal discharge at pre and post siltation period, sediment texture, and sedimentation of the canals. Descriptive statistics with the use of tables (as means total and percentages) was used for the analysis and presentation of data collected on canals discharge, sediment texture and suspended and dissolved sediments. The deposit consists of a fine sand fraction (76.3%) with a small amount of clay and silt of about 12.04% and 11.66% respectively. The average canal concentration for the suspended sediment concentration was found to be 8474.4 ton per annum. Although result of student t-test revealed no difference between the present and potential discharge the canals discharge has reduced by 47%. And this in turn affected the farms by reducing the total designed irrigable hectares of land. Many factors are believed to have contributed to the increase of sediments in the canals which include movement of farm tractors across the canals, poor irrigation practice by the farmers, and lack of adequate maintenance. It is recommended among other things that: there should be effective maintenance and monitoring of the canals through regular disilting and cleaning the canals by the participant farmers and the government.

Keywords: Canals, siltation, discharge, texture, accumulation.