Department of Environmental Science

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Browsing Department of Environmental Science by Subject "Assessment"

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    Assessment of the effects of land use/cover changes on surface water quality and treatment costs in river Malaba Catchment, eastern Uganda
    (Kyambogo University[unpublished work], 2022-10) Mbabazi, Sarah
    Changing land use and cover (LULC) is a major contributor to water quality degradation in various regions of the world. Unfortunately, there are not enough data on how LULC change affects water quality and prices in different catchments. Therefore, the research has covered gaps left by previous research by looking at three different aspects of the River Malaba catchment: first, the extent to which land use and cover have changed, second, the impact that land use has had on water quality, and finally, the impact that water quality has had on treatment costs. Sentinal-2 images of 2015 and 2021 were downloaded and analyzed using GIS. Water samples were picked at different land use/ cover types along the river and analyzed for physical-chemical as well as bacteriological parameters, statistical tools such as ANOVA at 95% confidence interval were done to understand land use/cover influence on water quality. Costs of water treatment influenced by water quality were analyzed retrospectively using data from the National Water and Sewerage Corporation and ANOVA at a 95% confidence interval. Results indicated LULC patterns shifted radically between 2015 and 2021, with most conversions to farming. The farmlands (15.3%) and built-up (1.0%) increased over time as woodlands (-2.8), grasslands (-13.2), and wetlands (-0.2) shrunk during the study period. Land use/cover significantly affected COD (P=0.023), Electrical Conductivity (P=0.004), and Nitrate levels (P=0.004), COD was observed highest in farmland and least in woodlands, and EC and Nitrates were highest in wetlands and also least in woodlands. Seasons also showed significance across all water quality parameters except for Feacal Coliforms (P=0.233) Total Phosphates (P=0.943) and Total Iron (P=0.147). Water quality parameters significantly affected the costs of Aluminium Sulphate, high-test hypochlorite, and polymer. Costs of water treatment were high downstream than the upstream, also in the rainy season than in the dry season. These findings suggest that River Malaba basin has been subjected to LULC changes as a result of human activities, which has repercussions on the quality of water, hence increasing the cost of water treatment. This has repercussions for the livelihoods and well-being of humans, for instance by increasing the likelihood of disease and limiting the use of water to provide material items such as food. Therefore, interventions should be implemented to conserve these catchment regions. In addition, because this study was conducted over a short period of time and with limited monitoring of water quality and trends in water treatment costs, future studies should be clear in examining LULC developments over time and how they relate to water quality and treatment costs.
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    Assessment of the impacts of land use and land cover changes on soil erosion in Ogwapoke micro-catchment, Northern Uganda
    (Kyambogo University[unpublished work], 2022-10) Ajidiru, Rita
    Several land use/cover changes have been observed in Ogwapoke micro catchment. Population increase, poverty, intensified and unsustainable farming practices and deforestation have been cited as the major drivers of land use/cover changes in the micro catchment. Land use/cover changes have been linked with increased surface runoff and soil erosion. However, there is a paucity of information to ascertain the impacts of land use/cover changes on soil erosion in Ogwapoke micro-catchment, Northern Uganda. Therefore, the study aimed to identify conservation measures and drivers that lead to continuous changes in land use/cover in order to combat the long-term effects of soil erosion on hydrological flow in Ogwapoke micro catchment. Specifically, the study aimed to (i) analyze and predict the spatial-temporal changes in land use/cover changes between 1986, 2003, 2020 and 2040 in Ogwapoke micro catchment; (ii) determine the effect of land use/cover change on soil erosion in Ogwapoke micro catchment; and (iii) assess the impact of land use/cover change on hydrological flow in Ogwapoke micro catchment. Landsat images for the study area for 1986, 2003 and 2020 were downloaded from Earth explorer. Unsupervised classification and the CA-Markov model were used to analyze and predict the land use/cover changes respectively. Questionnaires were also administered to 200 respondents in the study area to understand their perceptions of land use/cover changes including the drivers. The Revised Universal Soil Loss Equation (RUSLE) and the Soil and Water Assessment Tool (SWAT) models were used to assess the soil erosion and hydrological flow components (total yield, base flow, surface runoff, lateral flow, deep aquifer recharge, and actual evapotranspiration), respectively. The Pearson correlation coefficient was applied to assess the effect of land use/cover changes on hydrological flow components. Results showed that significant land use/cover changes have taken place in Ogwapoke micro catchment. Between 1986 and 2020, small-scale farmlands and built-up areas increased by 35.1% and 2.4%, respectively whereas bushlands, grasslands, wetlands and woodlands decreased by 11.7%, 7.4%, 2.4%, and 15.9% respectively. A similar pattern is projected to further intensify by 2040. Changes in land use/cover are mostly driven by over grazing, deforestation, poverty, bush burning, deforestation, and increased demand for food due to population growth. The changes in land use/cover had an effect on soil erosion in Ogwapoke micro catchment. Small