Active morphological factors determining the locations of sand mines in dry-river channels

Abstract

In Kenya, most of the construction sand is derived from dry riverbeds. Due to rampant nature in which sand mining is carried out in these rivers, adverse environmental and social effects have been reported. In order to ensure sustainable sand mining activities, this study assessed active morphological factors determining sand abundance in the seasonal river Tyaa in Kitui, Kenya. The study adopted quantitative research design. Purposive sampling was used to select river Tyaa due to uncontrolled sand mining that was taking place there. Systematic sampling at 20 meter intervals was used while collecting data at the stretches of the river channel, thus constituting 2,000 meters in total. Data on independent variables, namely the river channel’s width, depth, slope angles, bank position, weathering status, vegetation status, and erosion status was collected using physical measurements and logic guided observation. Binary logistic regression analysis was used to analyze the data, giving marginal effects and respective p-values. The study established four statistically significant factors responsible for sand abundance in the dry river channel’s namely depth (p=0.001), width (p=0.001), slope angles (p=0.001) and bank position (p=0.001). The study concluded that these factors should be observed while siting sand mines along dry river channels to mitigate adverse environmental effects. The study recommended that National Environmental Management Authority of Kenya should apply the findings of this study in the establishment of the locations of sand mines and monitoring of the mining process in line with the existing guidelines and regulations.