Land Use and Land Cover Change on Watershed Functions in Tungu-Naka River Sub-Catchment in Tharaka-Nithi County, Kenya
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Date
2025-12
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Kenyatta University
Abstract
Watersheds provide a main function of maintaining ecological balance and giving the most important services, like a home for biodiversity, water provision, and agricultural yields. The Tungu-Naka sub-catchment is an important hydrological unit that maintains different socio-economic activities for the communities in the watershed. The primary objective of this research was to assess the impacts of land use and land cover change (LULCC) on watershed functions in the Tungu-Naka River sub-catchment, Tharaka Nithi County. The specific objectives were to: (1) analyze the trends in land use and land cover in the Tungu-Naka watershed from 2002 to 2018, (2) identify and evaluate the driving factors of land use and land cover change in the Tungu-Naka sub-catchment between 2002 and 2018, and (3) assess the impacts of land use and land cover change on hydrological and ecological functions of the Tungu-Naka watershed. A mixed-methods research design combining both qualitative and quantitative approaches was employed. LANDSAT TM imagery from 2002, 2006, 2012, and 2018 was obtained from the Regional Center for Mapping of Resources for Development (RCMRD) in Kasarani. These images were used to analyze LULCC over the study period and partially evaluate its impacts on the Tungu-Naka sub-catchment through supervised classification. The study targeted households residing within the Tungu-Naka watershed, as well as key informants. SPSS software was used to examine the relationship between LULCC and watershed functions, specifically employing Pearson’s product-moment correlation coefficient (r). Key findings revealed significant LULCC, including the conversion of wetlands for farming, deforestation, the destruction of riparian zones, and increased settlement. Population growth and planting of eucalyptus were identified as primary drivers of LULCC. The main impacts observed included drying of wetlands and reduced river water volumes. Population growth, urbanization, and shifts in farming practices were highlighted as significant contributors to land use changes. The research identified riparian land restoration through tree planting as a common watershed conservation strategy within the sub-catchment. However, this approach has been largely unsuccessful due to tree-cutting by farmers and its limited application in the upper watershed zones. The study rejected the null hypothesis and accepted the alternative hypothesis, confirming a statistically significant relationship between LULCC and watershed functions. There is a need for regulated water abstraction in the rivers and for strengthening the capacity of the community members on the importance of protecting riparian land. From the findings, there is a need for a debate on the suitable land use activities that can be considered in the different watersheds. Consequently, there should be proper channels of communication by the community members to the relevant authorities in case of an illegal activity within the watershed.
Description
A Thesis Submitted to the Department of Geography in Partial Fulfilment of the Requirements for the Award of the Degree of Master of Arts in Geography (Geomorphology) in the School of Humanities and Social Sciences, Kenyatta University, December 2025.
Supervisors
1. Dr. Shadrack Murimi- Department of Geography
2. Dr. Antony Macharia- Department of Geography