sentences:  The area is subject to intense population pressure and conversion of forest lands into agricultural areas.As part of the Congo Basin, the Sangha River, drained by the tributaries rising in the northern humid region, and flowing into the southern region of the country, is the main water catchment.At the swampy estuary it forms several branches, and is also joined by the Likouala aux Herbes, Likouala, and Ubangi (Oubangui) rivers.