evidence: Benin has several rivers, the most important is the Pendjari river in the northwest (380 km), Couffo to the southeast (170 km), Ouémé to the center and south (150 km), Niger to the north and to the northeast and finally, the Mono to the west (100 km). Some of these rivers have important affluents. It is Niger with Mekrou (410 km), Alibori (338) and Sota (250 km) and Ouémé with Zou (150 km). [...] Okpara: more than 10 000 km2 for a length of 362 km. [...] Moreover, the Beninese territory has in the littoral zone, an important lacustrine and lagoon network of approximately 270 km2. The main lakes and lagoons, from west to east, Lake Toho, Lake Togbadji, Lake Ahémé (78 km2), Lake Nokoué (135 km2) and the lagoon of Porto-Novo. Further north of this range are very small dam lakes in the Ouémé and Mono plains. These different morpho-climatic and fluvial elements contribute to the formation of exploitable soils for agriculture.