It covers the Cameroonian part of Lake Chad, the Logone floodplain valley, rivers, rivers and induced flood zones, lakes, permanent or periodic swamps. IGN maps at 1/200,000th are those of the entire territory, sometimes covering less than 1%, so that the total area occupied is difficult to estimate. However, the area occupied by natural or artificial lakes, swamps and flood zones has been estimated at just over 7800 km2.