Browsing by Author "Gyawu, Emmanuella Serwaa"

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Hydro-Climatic Modelling of an Ungauged Basin in Kumasi, Ghana
    (Hydrol. Earth Syst. Sci. Discuss., 2018) Osei, Marian Amoakowaah; Amekudzi, Leonard Kofitse; Wemegah, David Dotse; Preko, Kwasi; Gyawu, Emmanuella Serwaa; Obiri-Danso, Kwasi
    The Owabi catchment which is about 69 km2 provides about 20 % of water needs of the Kumasi metropolis has been in recent times prone to high anthropogenic activities that threaten water resource management. The Soil-Water-AssessmentTool (SWAT) was used to assess the extent of these activities on the hydrology on the catchment from 1986 to 2015. Specifically, the model simulated historic and projected stream-flow and water balance. Initial results revealed the forest and topography 5 played major role in water loss at the catchment as evapotranspiration and surface runoff were the dominant modulating processes. Monthly calibration/validation of the model yielded satisfactory results with NSE (0.66/0.67), R2 (0.67/0.67), PBIAS (8.2%/8.0%) and RSR (0.59/0.58). Nine sensitive parameters of which the catchment slope (CN2) ranked principal were found to control runoff amounts into the river. The model uncertainty was also quite low as the 95PPU enveloped about 50% of the observed streamflow within a width of 0.45 - 0.55. Furthermore, future streamflow predictions were modelled under RCP2.6, 10 RCP4.5 and RCP8.5 climatic scenarios, and two landuse scenarios, landuse category 1 and 2 (LU1 and LU2). An increasing trend of the downscaled rainfall totals between 2021 to 2050 for all RCPs were observed. This will positively impact streamflow generation at the catchment under LU1. There is an expected deficit of streamflow amounts under LU2 relative to LU1, and a marginal reduction as compared to the baseline. In general, the model proved efficient in determining the hydrology parameters in the catchment and therefore has potential to be used for further modelling of water quality and pollution to aid 15 effective water resource decisions at the catchment. 1 Introducti
  • Thumbnail Image
    Item
    The impact of climate and land-use changes on the hydrological processes of Owabi catchment from SWAT analysis
    (Journal of Hydrology: Regional Studies, 2019-07-24) Amekudzi, L.K.; Osei, Marian Amoakowaah; Wemegah, David Dotse; Preko, Kwasi; Gyawu, Emmanuella Serwaa; Obiri-Danso, Kwasi
    Study region: The 69 km2 Owabi catchment in Ghana. Study focus: The Soil-Water-Assessment-Tool (SWAT) was used to assess the hydro-climatic variability resulting from anthropogenic activities from 1986 to 2015. Specifically, the model simulated historic and projected stream-flow and water balance. Future stream-flow projections were modelled for three climate ensembles under three different representative concentration pathways (RCPs) for two land-use categories. New hydrological insights for the region: Initial results revealed that forest and topography played major role in water loss, whereas evapotranspiration and surface runoff were the dominant modulating processes. Monthly calibration/validation of the model yielded acceptable results with NSE, R2, PBIAS and RSR values of 0.66/0.67, 0.67/0.67, 8.2%/8.0% and 0.59/0.58 respectively. Uncertainty was fairly low and the model enveloped about 50% of the observed stream-flow. The RCP projections for all land use categories showed decreasing rainfall and streamflow trends. The model proved efficient in determining the catchment hydrology parameters and has potential to be used for further modelling of water quality and pollution to aid in effective water management.