ASSESSMENT OF MID-CENTURY CLIMATE CHANGE IMPACTS ON MONO RIVER’S DOWNSTREAM INFLOWS.

Author : Nina Rholan HOUNGUE, 2018.

Summary:

Abstract
In the current context of global climate change and variability, it is important to undertake river
flow projection in order to improve watershed management. This is needed to put in place relevant
actions in order to improve communities’ security. Hence, this study aims at assessing the impact
of the mid-century climate change on Mono River downstream inflows at Athiémé (Benin). The
projections from the regional climate model REMO, under the scenarios RCP 4.5 and RCP 8.5
were used to force the hydrological model HBV-light. Within the period 2018-2050, temperature
will increase and seasonal cycle of rainfall will change throughout the watershed: in the south, the
second rainfall peak which normally occurs in September will be extended to October with a
higher value; in central and northern parts, there will be late unset of rainfall, shorter rainy season
and higher peaks. Consequently, the mean hydrograph will shift rightward, increase in amplitude
and the period of high flow will be shortened. Under RCP 4.5, the lowest maximum flow will be
recorded in 2031 (116 m3/s) whereas the highest is expected in 2024 (1236 m3/s). Flood prone
areas vary between 6.2% to 20.1% of Athieme’s land surface. For RCP 8.5 the lowest maximum
flow is projected for 2033 (123 m3/s) and the highest for 2034 (1150 m3/s), with flood prone areas
ranging from 6.4% to 19.2%. Thus, it is recommended to undertake thorough risk assessment on
one hand, and to account for both high and low flow situations in Mono watershed management
strategies.

DOWNLOAD DOC