During World War II, Lake Piso functioned as a military base for Allied seaplanes.[1][2]

Lake Piso overflowed its banks at least twice in 1998, causing heavy flooding in Garwular District. Flooding in August 1998 occurred due to a blockage of the narrow inlet connecting the lake to the Atlantic Ocean, damaging some homes.[3] Additional flooding in September and October, brought about by heavy rains, affected over twenty settlements, causing at least ten deaths, leaving thousands homeless, and forcing others to leave their homes.[4][5][6][7][8] The floods led the government of Liberia to declare the area a "disaster zone".[9]

On December 13–14, 2002, the Papa Friends 2000 capsized in Lake Piso, at the confluence of the lake and Mafa River. The overcrowded wooden ferry was transporting approximately 200 passengers, most returning from the funeral of a local footballer. Only 15 people were rescued; the rest drowned and were recovered or presumed dead.[10][11][12][13][14]

A nature reserve was designated near Lake Piso in 1999[15] and, as of 2004, the Lake Piso wetlands, covering an area of 76,091 ha (761 km2), were Liberia's only designated wetland of international importance.[16]