Hāmākua Marsh and the adjacent Kawainui Marsh make up the largest remaining wetland habitat in the State. It is a wildlife sanctuary owned by DLNR and home to four species of endemic and endangered waterbirds. The four endemic waterbird species are: 'Alae 'Ula, Ae'o, 'Alae Ke'o Ke'o, and Koloa Maoli.

The area has a rich cultural and geographical history. The area was a good source for inland fishing and wetland taro production, and supported a large population of native Hawaiians.

Hāmākua Marsh used to be a stream flowing from Kawainui Marsh to Kaʻelepulu Marsh (now Enchanted Lake) but the water flow has been diverted. The Marsh now depends fully on rainfall on the hillside rising up from the Marsh, as well as run off from parts of Kailua town.

Source: https://healthyclimatecommunities.org/home/restore-hamakua/