Date of Award

1-2015

Document Type

Thesis

Degree Name

Master of Science (MS)

College/School

College of Science and Mathematics

Department/Program

Earth and Environmental Studies

Thesis Sponsor/Dissertation Chair/Project Chair

Clement A. Alo

Committee Member

Duke U. Ophori

Committee Member

Joshua C. Galster

Subject(s)

Hydrologic models--White Volta River (Burkina Faso and Ghana), Hydrologic models--Climatic factors, Groundwater flow --Computer simulation, Groundwater flow--Climatic factors, Streamflow--White Volta River (Burkina Faso and Ghana)

Abstract

The Nasia River, a tributary of the White Volta River system in Northern Ghana, is an important water resource for the area. In this research, a hydrological model that is able to simulate surface and subsurface flows in the Nasia catchment reasonably well was developed. The model was calibrated and verified using discharge and hydraulic head observations for the period 2000-2010. The complete simulation showed that the model was able to simulate the streamflow at the Nasia outlet quite well (Nash-Sutcliffe coefficient of 0.65, and correlation coefficient 0.805). The flow dynamics at three groundwater monitoring stations (HAP5, HAP 10, and HAP11) were also realistically reproduced although the model generally overestimated the heads. For the purpose of climate change impact assessment, the calibrated/validated model provided a baseline condition to quantify evolving sensitivities of the Nasia catchment to climate variability and change. Climate projections drawn from eight Coupled Model Intercomparison Project phase 5 (CMIP5) global climate models (GCMs) were used to explore potential impacts on the catchment over three future time slices (2011-2025, 2026-2040, 2041-2055). When the climate scenarios were applied to the flow model, increasing trends in simulated évapotranspiration and streamflow from 2011 through 2055 were shown for all but one of the GCM scenarios. Projected rainfall changes dominated over évapotranspiration changes in terms of their impacts on streamflow for all three time periods. The results thus indicate that streamflow responses to climate changes in the Nasia Catchment are mainly driven by rainfall changes. The results also suggests that the conjunctive use of surface and groundwater resources to support local irrigation schemes in the basin might be a sufficient buffer against the effects of changing rainfall patterns on agriculture in the basin.

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