Abstract:
The study assessed the impacts of climate change on hydrology of Latonyanda River
Quaternary Catchment (LRQC). The Soil and Water Assessment Tool (SWAT) model
played a huge role in climate change impact analysis because it helped in improving
the understanding of climate change impacts on hydrology as well as in determining
mitigation measures. Arc-GIS 10.7 model with a compatible version of Arc-SWAT
interface was used to model the impact of climate change on hydrology of LRQC. The
SWAT model set up for calibration and validation was done using historic data. The
SWAT Output viewer was used to view model performance results. Model
performance was assessed based on scatter plots, graphical fits and performance
measures which include Nash Sutcliffe Efficiency (NSE), percent bias (PBIAS), and
coefficient of determination (R2). Climate change projections from Conformal Cubic
Atmospheric Model (CCAM) were used to forecast the impact of climate change on
hydrology. The historical, near future and far future periods are 34 (1981-2014), 30
(2023-2052) and 30 (2053-2082) years, respectively. To determine trends on annual
average flows and statistical significance for historical, near and far future, regression
analysis was used. Regression analysis showed that significance levels of the p-value
for historical, near, and far future annual flow trends is 0.010, 0.034 and 0.030,
respectively. The model performance was good and acceptable with NSE, PBIAS, and
R2 for both calibration and validation as 0.67 and 0.68, -9.3 and -13.4%, and 0.70 and
0.69, respectively. The findings of the current study show that streamflow amount is
decreasing over time with annual average totals of 4.849, 2.340 and 2.051 m3/s for
the historical near, and far future respectively. The results will aid in raising awareness
to the community and municipality governing around LRQC. This study recommends
venturing into smart development technologies to minimise the impact caused by
climate change. Further climate change related studies should be conducted as there
is a gap in ungauged catchments. The expansion of the current study to include land
use impacts on hydrology is recommended.
