The Sourou River (Bagouè) functions as both a defluent (from July to November) and a tributary (from December to April) of the Mouhoun (Black Volta) River. Its upper valley in Mali extends 90 km and intersects the Samori region. The construction of the Lery Dam in Burkina Faso in 1986 has significantly increased water levels, enhancing biodiversity in the Sourou floodplain in Mali, benefiting waterbirds and fish populations. The Site hosts diverse habitats, including lakes, forested floodplains, flooded grasslands and savannah, supporting rich biodiversity and natural resources. It is home to vulnerable species such as the hippopotamus (Hippopotamus amphibius), African manatee (Trichechus senegalensis) and crowned crane (Balearica pavonina). The Site provides food resources (fish, mollusks, and grains) and freshwater for consumption and irrigation, sustaining local livelihoods and food security. It regulates hydrology, offering flood control, groundwater recharge, and erosion protection, and provides a natural laboratory for significant scientific research and cultural heritage. Despite the Site’s value, its ecological character is threatened by drainage, canalization and agricultural expansion. Pollution from agriculture and urban wastewater, along with climate change impacts such as droughts and temperature extremes, further endanger the Site.