Its size and shape depends on the season and amount of water flowing into the swamps, especially from the Mbereshi River to the southeast, its main supplier.

Floating islands of sedge are usually found in an east–west line across its middle, which may effectively cut it in two, and at times vegetation has covered much of the southern half.

The importance of the Mofwe lies in its fishery, which attracted Mwata Kazembe to settle in the town of Kanyembo on its eastern edge in the 19th century.

[1] The Mofwe does not have a definite shore and is not easily accessed, being lined by a dense band of very tall reeds, and having floating rafts and islands of sedge which change its margins and shape frequently.

Local fishermen paddle dugout canoes along narrow channels through the reeds to reach open water.