LAND USE, LAND COVER CHANGES AND IMPLICATIONS ON SURFACE WATER ACREAGE IN KOITOBOS RIVER CATCHMENT IN TRANS NZOIA COUNTY, KENYA.

Abstract

Globally, many countries are facing pressure to meet the livelihood needs of their fast-increasing populations. This often leads to overuse of natural resources and consequent encroachment on fragile ecosystems such as river catchments and riparian areas, mostly in developing countries. This has resulted to unsustainable land use practices coupled with land degradation exerting pressure on land and water resources which are basic to ecosystem livelihood. Overally, this study was to assess the implication of land use, land cover changes on surface water acreage in the Koitobos River catchment between the period 1992 to 2022. Specifically assessed the extent of land use/land cover changes within the river catchment, examined the variations in surface water acreages in Koitobos River, and evaluated land use practices for sustainable land and surface water management in the study area. Land use/land cover data was based on Landsat images pertaining to the period of study, using descriptive and correlation research design. The Google Earth Engine (GEE) and Remote sensing techniques were used for acquisition of secondary data and social economic data was collected using survey questionnaires for validation feedback and ground trothing. A sample size of 384 respondents was drawn from a target population of 203,821 residents according to Kenya National Bureau of Statistics 2019, (KNBS) within the study area. The data was analyzed using SPSS software version 25 and Microsoft excel for analysis. From the findings of Land Use, Land Cover Change in the selected years, 1995, 2009 and 2022, due to data availability and consistency, showed that Agricultural Land, covered a majority area of the Catchment depicting, 26,853Ha, (58%), 32,438 Ha (70%), and 36,118Ha (77.68%) respectively. Followed by bare land area which covered 14,915 Ha (32%), 8,093 Ha, (17%) and 6175 Ha (13.28%) of the entire catchment area extremely decreases transitionally as the Agricultural land increases due to the pressure exerted on the resource. The Forest Land showed drastic decreasing trend through the transitional period from 2242 Ha (5%) to 1647 Ha (4%) and then 222 Ha (0.48%), due to increasing demand for more space by the growing population as per (KNBS) reports, which increasingly results to deforestation activities within the catchment. Water resources within the Koitobos catchment showing an increasing trend from the year, 1995, 2009, and 2022 as follows, 2332 Ha (equivalent to 5%), 3803 Ha (equivalent to 8%), and 3521 Ha (equivalent to 7.6%) and this resulted from the artificial digging of new water pans, dams and protected water points and streams. The population of the study area in 2009 was 166,524 persons and 203,821 persons in 2019, within an area of 465.3square Kilometers with residents’ density of 438.0 per square kilometer. Interviews and focus group discussions (FGDs) viewed that integrated approach on sustainable land management will be key in relieving the pressure on the natural resources. The study found out that due to 2% (percent) annual population change of 2009- 2019, resulted in an increased demand for food production within the environment where arable land couldn’t be expanded therefore concluded that environmental policies and laws needed to be adopted. The study therefore recommended the adoption of sustainable land use management practices that continually heal the land and conserve biodiversity by imploring catchment plans.