Quarrying and Land Degradation in Nyakach Sub County, Kenya

Land degradation is a problem facing humanity on earth today as it threatens food security as well as viable land use activities. This study considered quarrying as a form of land degradation using human beings as geomorphic agents. The study established the extent of quarrying effects on land degradation on land use activities such as agriculture, transportation and biodiversity. The indicators of land degradation were soil erosion marked by presence of gullies, sand budget analysis and reference state analysis. The study used cross sectional study and quasi-experimental research designs involving measurement of gully dimensions, sand budget and reference state analysis of drainage channels. GPRS technology from window’s tablet with Google earth software (CNES/Airbus, 2018) was used for capturing spatial data. The results were: gullies were cascaded all over the area with an average depth of 3.9m reducing portions of agricultural and grazing lands as well as cut transport lines. Reference state analysis showed that neem plant and monitor lizards species peculiar to the drainage channels in Nyakach are endangered. Sand budget analysis showed 5,118t and 8,986t of sand were appropriated during dry and wet seasons respectively with an annual gravel loss of 0.0128t/Km2 or 3.6t/Ha. equivalent to 9935.5t/y. Consequently, riparian and farmlands were invaded during dry seasons causing major degradation. The study recommends: terracing, building of gabions, afforestation and adoption of alternative land use activities to control land degradation.