A Ramsar-protected seasonal valley in southwestern Niger, where Sahel meets Sudan.
Dallol Maouri
Dallol Maouri is one of the great dry valleys of southwestern Niger, a broad seasonal watercourse that runs roughly north to south through the Dosso Region and connects, near the village of Bana, to the parallel Dallol Foga before the system ultimately reaches the Niger River. Together with the Dallol Bosso and the Dallol Foga, it belongs to the ancient, fossilized drainage network of the Iullemmeden Basin, valleys that once carried large tributaries of the Niger and that today function mainly as seasonal wetlands.
The valley is ecologically distinctive because it bridges the Sahel and Sudan climate zones. Its upper reaches, in the Aréoua landscape, sit at the climatic transition with annual rainfall of roughly 650 millimeters, while its lower reaches, in the Dendi landscape, are firmly Sudanian with about 850 millimeters of annual rain. During the wet season, water flows down the valley and its many small tributary channels; in the dry months these recede into scattered ponds known locally as mares, whose unpredictable filling is closely tied to the region's recurrent flooding events.
The Dallol Maouri is also one of Niger's most heavily settled valleys. Irrigation agriculture, palm groves, fisheries, and traditional salt production along the lower valley give the landscape a strong human dimension that sits alongside its ecological importance as a wetland of international standing.
