Kawainui Marsh

Kawainui — 'the great water' — is the largest remaining wetland in Hawaiʻi, eight hundred thirty acres of marsh in Kailua that was once a bay, then a lagoon, then the biggest fishpond in the islands. Six thousand years ago it was open ocean; the sandbar that closed it into a lagoon formed about twenty-five hundred years ago, and by two hundred years ago the Hawaiians had converted the whole lagoon into a four-hundred-acre fishpond so productive it fed the aliʻi of Koʻolaupoko — the chiefs who made Kailua their seat of power.

Two heiau overlook the marsh. Ulupō Heiau, on the ridge above the water, is a massive stone platform where the aliʻi conducted the ceremonies that governed the fishpond and the district; it was already ancient when the chiefs used it. Below the heiau, the marsh is a living system — four endangered Hawaiian waterbird species, a Ramsar Wetland of International Importance since 2005, a flood basin protecting the town that grew up around it.

The marsh's guardian is Hauwahine, the moʻo — the lizard goddess who is said to live in the waters still, a protector deity whose presence is cited in the educational guides the state publishes about the place. The marsh is where Honolulu's urban sprawl stops — the last unbuilt basin on windward Oʻahu, kept because the community fought for decades to keep it wet.