It has a tropical climate, and it is one of the wettest areas in Oʻahu, averaging nearly 300 inches per year in parts of the valley.

It had fresh water, abundant seafood, and a stable supply of taro, which was grown in fields with advanced irrigation systems.

However, around the time of King Kamehameha's unification of Hawaii in the 1800s, the community fell into steep decline due to foreign diseases, sugarcane cultivation and the military's use of the valley as a World War II jungle warfare training center, through the arrival of Europeans.

Oʻopu naniha (Stenogobius hawaiiensis), a native freshwater fish, can be found in the streams of the lower valley.

Bird species that can be found in the lower valley include Pacific golden plover (Pluvialis fulva), ruddy turnstone (Arenaria interpres), sanderling (Calidris alba), wandering tattler (Tringa incana), ʻaukuʻu (black-crowned night heron, Nycticorax nycticorax), ʻalae keʻokeʻo (Hawaiian coot, Fulica alai), and ʻalae ʻula (Hawaiian gallinule, Gallinula chloropus sandvicensis).

Further up the valley, in the wetter areas, the dominant vegetation consists of mountain apple (Syzygium malaccense), strawberry guava (Psidium littorale), ti (Cordyline fruticosa) and bamboo.