Satellite Remote Sensing and GIS based Watershed Analysis: Implications for Soil and Water Conservation Practices in the Denkyira Watershed, Ghana (original) (raw)
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Morphometric Analysis of Offin River Basin using Remote Sensing and GIS Technology in Ghana
International Journal of Engineering Research and, 2018
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Assessment of past and future land use/cover change over Tordzie watershed in Ghana
Frontiers in Environmental Science
Land use/ land cover (LULC) change has been identified as the main driving force of global change. The study investigated LULC change in Tordzie watershed in Ghana and predicted the future development. The supervised classification procedure was applied to Landsat images of 1987, 2003, and 2017. The cellular automata–Markov model embedded in IDRISI 17 software was employed to model LULC for the years 2030 and 2050. The trend of LULC change was exploited from 1987 to 2003, from 2003 to 2017, and projected to 2030 and 2050. Settlement and crop land, respectively, increased from 2.68% to 16.46% in 1987 to 3.65% and 53.47% in 2003 and finally to 20.61% and 58.52% in 2017. Vegetation cover declined from 23.2% in 1987 to 13.9% in 2003 and finally to 11.3% in 2017. The annual rate of change was determined. In 2030 and 2050, the dominant land use type will be crop land (56%). However, it decreased between 2017 and 2030 by −1.73%. The findings of the study are very relevant to land and water...
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Land cover and land use changes in Kenya's Rift Valley have altered the hydrologic response of the River Njoro watershed by changing the partitioning of excess rainfall into surface discharge and groundwater recharge. The watershed contributes a significant amount of water to Lake Nakuru National Park, an internationally recognized Ramsar site, as well as groundwater supplies for local communities and the city of Nakuru. Three land use maps representing a 17-year period when the region underwent significant transitions served as inputs for hydrologic modeling using the Automated Geospatial Watershed Assessment (AGWA) tool, a GIS-based hydrologic modeling system. AGWA was used to parameterize the Soil and Water Assessment Tool (SWAT), a hydrologic model suitable for assessing the relative impact of land cover change on hydrologic response. The SWAT model was calibrated using observation data taken during the 1990s with high annual concordance. Simulation results showed that land use changes have resulted in corresponding increases in surface runoff and decreases in groundwater recharge. Hydrologic changes were highly variable both spatially and temporally, and the uppermost reaches of the forested highlands were most significantly affected. These changes have negative implications for the ecological health of the river system as well as Lake Nakuru and local communities.
Journal of Geography, Environment and Earth Science International
Issues of global warming and climate change as a result of the aggravation of greenhouse gases and other anthropogenic activities have remained a global discourse since time immemorial. Climate change has increased temperatures and reduced the amount and distribution of rainfall. This has become a major concern to scholars and researchers alike. This study, therefore, investigates the impacts of climate change in the North Eastern part of Ghana between 1985 and 2016. The study looks at land use and land cover changes in the watersheds of the Tono Reservoir using satellite images. Satellite images were extracted and imported into ERDAS 2010 for processing. Layer stacking was performed to put all the bands together as one file. Sub-setting was done to extract the Tono Reservoir and its environs. Climate variables such as rainfall, temperature were analysed to find their relationships with water levels of the Tono reservoir. It was found that rainfall and water levels of the Tono reser...
International Journal of River Basin Management, 2015
Soil erosion is one of the natural resources which can be influenced by Land use land cover change (LCC). The main influencing factor for land use land cover change is the increase of population, which in turn resulted in land degradation. This study aimed at modeling and analyzing LCC and its effect on soil erosion. The study was conducted in the highlands of, Blue Nile Basin, Ethiopia. Three Landsat images (1986, 2000 and 2016) were used to analyze the LCC. Supervised classification using maximum likelihood algorism was used to analyze the LCC. Four land cover types (LCTs) cropland, forest, and grassland and shrubland were defined. Multi-criteria decision analysis (MCE) using the Analytic Hierarchy Process (AHP) was used to prioritize the most influencing factor for soil erosion. Five major factors; land use, slope, soil types, Topographic Wetness Index (TWI) and altitude were considered to analyze the erosion hotspot area. The result showed that cropland and grassland increased from 41.6% and 15.4% in 1986 to 58.8% and 28.3% in 2016, respectively. However, shrubland and forest decline from 32.3% and 10.6% in 1986 to 5.6% and 7.3% in 2016, respectively. The AHP analysis showed that LCT is the most contributors for erosion. It is observed that free grazing in the area is the common practice which is the main contributor to erosion. Hence, 50% of the gully erosion is influenced by LCT. The resultant erosion risk map shows that 1.12% of the area lies under the low-risk zone, whereas 19.02%, 72.67% and 7.2% of the total area fall in medium, high and very high-risk categories respectively. The results verified by field data collected and the judgment of the experts.
Using Geospatial Information Component to Monitor the Watersheds along the Densu Basin in Ghana
Journal of Geographic Information System, 2016
The Densu basin is a coastal river catchment in southern Ghana and a typical rural community like all other rural settlements in Ghana. It is the only basin amongst 43 other basins of the country that supplies water to two regional capitals of Ghana, namely, the capital city of Ghana, Accra and Eastern regional capital, Koforidua. The qualities of these water resources vary naturally and widely depending on climate, season, and the geology of the bedrock, as well as anthropogenic activities. The primary aim of this research is to determine data requirements for efficient and costeffective development of a Geographic Information System (GIS) to map and detect the extent of the sources of the watersheds and how to protect the environment for continuous supply of water. Among the Nine catchment areas, only one catchment WSA_05 (Koforidua Township) was determined to have a very high risk of being vulnerable and therefore required urgency to protect environment for continuous supply of water. Four catchment areas WSA_02 (Weija Dam), WSA_03 (Apedwa-Asafo), WSA_06 (Suhum) and WSA_09 (New Tafo) were determined to have a high risk of being affected and therefore there was the need to protect the environment for continuous supply of water. Ghana as a country will have to take a responsible step in protecting its water body and its environment to enable continuous and sustainable supply of water to its citizens. This study therefore reveals the state of the water users and how urgent it environment needs to be protected.
Land use and land cover changes and Soil erosion in Yezat Watershed, North Western Ethiopia
Biomass GIS NDVI Land-use and land-cover Remote sensing RUSLE a b s t r a c t Soil erosion affects land qualities and water resources. This problem is severe in Ethiopia due to its topographic features. The present research was aimed to estimate spatiotemporal changes in land-use/ land-cover pattern and soil erosion in the Yezat watershed in Ethiopia. This study was carried out by using landsat imageries of 2001, 2010 and 2015. Images were classified into categories using supervised classification by maximum likelihood algorithm. They were also classified into different biomass levels by using Normalized Difference Vegetation Index (NDVI) analysis. Revised Universal Soil Loss Equation modeling was applied in a GIS environment to quantify the potential soil erosion risk. The area under grassland, woodland and homesteads have increased by 610.69 (4%), 101.69 (0.67%) and 126.6 ha (0.83%) during 2001-2015. The extent of cultivated land and shrub/bushland was reduced by 323.43(0.02%) and 515.44 ha (3.41%), respectively, during the same period. The vegetation cover in the watershed decreased by 91% during 2001-2010, and increased by 88% during 2010-2015. Increase of NDVI values indicates better ground cover due to implementation of integrated watershed development program in the region. The estimated annual soil losses were 7.2 t ha À 1 yr À 1 in 2001, 7.7 t ha À 1 yr À 1 in 2010 and 4.8 t ha À 1 yr À 1 in 2015. Management interventions are necessary to improve the status and utilization of watershed resources in response to sustainable land management practices for sustainable livelihood of the local people.
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Soil erosion is one of the most critical environmental problems in the sustainable development of agriculture and natural resources. Ethiopia is facing severe soil erosion problems. The present study was carried out in the Megech River catchment, Lake Tana Basin, North Western Ethiopia. The present study aims to identify the sensitive soil erosion-prone sub-watersheds in the Megech River catchment. ASTER-DEM (Advanced Space-borne Thermal Emission and Reflection), a 30 m spatial resolution digital elevation model (DEM), was used to delineate the sub-watersheds and drainage networks through spatial Analyst and ArcHydro extension of ESRI ArcGIS v10.6.1 software. The cloud-free optical satellite data got from Landsat-8 Operational Land Imager (OLI) has been used to update the drainage network of the present study area. The study area was divided into four sub-watersheds: WS-1, WS-2, WS-3, and WS-4. The primary, linear, and areal drainage morphometric parameters were calculated by applyi...
2020
Characteristics of watershed were not well investigated as global also in Fincha, Ethiopia. Fincha watershed is the most erosion prone area in the highlands of Ethiopia towards to Fincha dam.Therefore, the aim of this study was toanalysisFincha watershed characteristics based on land use/cover, soil type and slope classification and to identify soil erosionpronearea using Arc-GIS and Arc-SWAT model.Accordingly, nine major land use/covers were identified. Those were:- bush land, dominantly cultivated, moderately cultivated, irrigated land, grass land, water bodies, swamp area, urban and woodland open. From these most part of the catchment was under cultivation with 67.677% of the total area. In the same way, the major soil types identified were: - chromic luvisols, chromic vertisols, dystric cambisols, eutric cambisols, eutric nitosols, eutric regosols, haplic phaeozems, humic cambisols and water. Cambisols were covered the highest percentage, 39.98% area of the catchment.Subsequentl...