Impact of future climate change and anthropization on the discharges of the So'o watershed (South Cameroon)

Abstract

<p>The purpose of this article is to get an idea of ​​the evolution of the flows of the So’o basin in the relatively near future (2022-2060), but also in the distant future (2061-2100). In this perspective, the Cellular Automata (CA) -Markov was used to predict the evolution of the future land use of the basin, and the outputs of three regional climate models/RCMs (RCA4, RACMO22T and CCCma) were used to predict future climate change. Distribution mapping was retained as a method of correcting the precipitation and temperature biases of the outputs of the climate models used. The SWAT (Soil and Water Assessment Tool) model was used to simulate the future flows of the So’o. The results obtained show that a change in precipitation in accordance with the forecasts of the CCCma and RACMO22T models will be the cause of a decrease in the runoff, except under the RCP8.5 scenario during the second period (2061-2100), where we will note an increase compared to the historical period of approximately + 4%. This decrease will mainly affect the months of autumn, and the decades 2020, 2040 and 2070 will be the most affected. Concerning the RCA4 model, the results obtained show that a change in precipitation following its forecasts will cause an increase in runoff of more than 50%, regardless of the period and the scenario taken into account. In general, this increase will be greatest during the dry seasons (winter and summer), and the decades at the end of the century (2080s to 2100s) will be the wettest. An increase in discharges was noted in certain cases despite a decrease in rainfall, in particular in the case of flows simulated for the first period (2022-2060) from the outputs of the CCCma model. This seems to be a consequence of the increase in impervious areas, insofar as the runoff also increases during this period according to the model. The results of this study could be used to strengthen the management of future water resources in the basin and the entire region.</p><p><strong>Keywords:</strong> So’o, RCMs, Climate Change, Anthropization, SWAT</p>