Abstract:
Understanding the susceptibility of Watershed is very crucial issue in identification of the
health status of water bodies. The watershed characteristics such as size, shape, slope,
drainage density, land use, geology, soil type etc. are some common factors affecting the
health of watershed. As this watershed characteristic can influence the vulnerability to
pollution, it’s better to assess them. Assessing Watershed vulnerability and identification of
risk is very important input for understanding the status of watershed health condition. Gojeb
Watershed was investigated to indentify the extent of vulnerability so that parts and zones of
vulnerability extent to be well defined. Therefore, the aim of this study was to assess the
vulnerability of Gojeb River watershed using weighted overlay and Analytical Hierarchy
techniques. The method used to study Gojeb Watershed was done by using the combination of
Software. GIS spatial analysis tool was used to produce the maps that show the vulnerable
parts of the Watershed. Using these maps AHP analyzed which parts of Gojeb Watershed
were affected with respect to the extent of susceptibility in percentage of area coverage. The
analysis was done using five main factors that influence water quality. Land use land cover,
soil type, annual average rainfall, slope gradient, and bedrock type were the main factors
considered based on their contribution to water pollution. The main findings obtained were
identifying the vulnerable parts of the watershed and showing it by thematic maps.
Accordingly, 0.24 % were very high vulnerable, 5.7 % were high vulnerable, 38.6 % were
moderately vulnerable, 55 % were low vulnerable and 0.47 % were very low vulnerable to
contamination. This study clearly defined and relates how land use, slope, precipitation,
geology and soil factors affect the watershed of Gojeb River. Therefore, It is concluded that
Gojeb River Watershed to be exposed to vulnerability to contamination in some parts and
hence, need reclamation work. The recommended measures for reclamation were to take the
action of reforestation and terrace building.
