Nonopapa Lake is an ephemeral lake on the western shore of the south central region of the island of Niûihau. It is separated from the Pacific Ocean by a stable dune measuring 13âÂÂ16â¯ft high and 260â¯ft wide.
The lake measures around 370â¯acres (150â¯ha) during the rainy seasons. Together with Halaliûi Lake, Halulu Lake, and various ponds on the island, Niûihau can hold up to 2,000â¯acres (810â¯ha) of water. During dry periods on the arid island, the lake transforms into a dry reddish flat punctuated by small saline lakes.
According to Hawaiian linguists Mary Kawena Pukui, Samuel H. Elbert, and Esther T. Mookini, Nonopapa has the literal meaning of 'invalid' in the native Hawaiian language, likely in reference to the transient nature of the lake.
The Makaloa sedge (Cyperus laevigatus) grows along its shore and was traditionally used by the Native Hawaiians for weaving the Makaloa mats. The lake bed was also used for the cultivation of sugarcane, famously growing "in the sand with only leaves protruding". Sheep were sheared in shacks built between the lake and beach dunes.
The lake provides natural wetland habitats for Hawaiian bird species including the ûalae keûokeûo (Hawaiian coot), aeûo (Hawaiian stilt) and koloa maoli (Hawaiian duck). The lake is also used for mullet farming, as young fish enter the lake from the sea through lava tubes. Hawaiians bring the baby pua (mullet fish) from the sea in barrels, release them during the rainy seasons, and catch the grown fish when the water recedes in the summer. The grown fish are often sold at market on Kauaûi and Oûahu.