Preprints
https://doi.org/10.5194/hess-2017-729
https://doi.org/10.5194/hess-2017-729
 
15 Jan 2018
15 Jan 2018
Status: this preprint was under review for the journal HESS but the revision was not accepted.

Hydro-Climatic Modelling of an Ungauged Basin in Kumasi, Ghana

Marian Amoakowaah Osei, Leonard Kofitse Amekudzi, David Dotse Wemegah, Kwasi Preko, Emmanuella Serwaa Gyawu, and Kwasi Obiri-Danso Marian Amoakowaah Osei et al.
  • Kwame Nkrumah University of Science and Technology, Ghana

Abstract. 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-Assessment-Tool (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 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, 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 effective water resource decisions at the catchment.

Marian Amoakowaah Osei et al.

 
Status: closed
Status: closed
AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment
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Status: closed
Status: closed
AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment
Printer-friendly Version - Printer-friendly version Supplement - Supplement

Marian Amoakowaah Osei et al.

Marian Amoakowaah Osei et al.

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Latest update: 25 Jun 2022
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Short summary
The study focussed on the negative implication of anthropogenic invasion at the Owabi catchment. Results from modelling the hydro-climate showed the main pathway of water loss were evapotranspiration and surface runoff. Streamflow generation is projected to increase slightly under two landuse scenarios. This, if properly harnessed will boost water production and supply to meet rising demands for the Kumasi metropolis.