River flow in the Songwe sub-basin is
predicted to alter due to climate change, which would have an impact on aquatic habitats,
infrastructure, and people’s way of life. Therefore, the influence of climate
change should be taken into account when making decisions about the sustainable
management of water resources in the sub-basin. This study looked into how
river discharge would react to climate change in the future. By contrasting
hydrological characteristics simulated under historical climate (1981-2010)
with projected climate (2011-2040, 2041-2070, and 2071-2100) under two emission
scenarios, the effects of climate change on river flow were evaluated (RCP 4.5
and RCP 8.5). The ensemble average of four CORDEX regional climate models was built
to address the issue of uncertainty introduced by the climate models. The SWAT
model was force-calibrated using the results from the generated ensemble
average for the RCP 4.5 and RCP 8.5 emission scenarios in order to mimic the
river flow during past (1981-2010) and future (2011-2100) events. The increase
in river flows for the Songwe sub-basin is predicted to be largest during the
rainy season by both the RCP 4.5 and RCP 8.5 scenarios. Under RCP 8.5, the
abrupt decrease in river flow is anticipated to reach its maximum in March
2037, when the discharge will be 44.84 m3/sec, and in March 2027,
when the discharge will be 48 m3/sec. The extreme surge in river
flow will peak, according to the RCA4, in February 2023, in April 2083 under
RCP 4.5, and, according to the CCLM4 and RCA4, in November 2027 and November
2046, respectively. The expected decrease and increase in river flow throughout
both the dry and wet seasons may have an impact on the management of the
sub-water basin’s resources, biodiversity, and hydraulic structures. The right
adaptations and mitigation strategies should be adopted in order to lessen the
negative consequences of climate change on precipitation, temperature, and
river flow in the sub-basin.
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