He'eia, comprising over 2,500 acres, was a primary population center for ancient Hawaiians in the windward side of Oahu. As an Ahupua'a (extending from summit of mountain to sea), it was able to sustain the ancient population through fishing and agriculture. Playing a major role in He'eia Ahupua'a is the He'eia Stream, which begins in the mountain area near Pu'u Keahiakahoe and is joined by Haiku, Ioleka'a and Puolena Streams on its way to Kane'ohe Bay. Taro was grown along the He'eia Stream in terraced lo'i. Plentiful algae, mullet and moi thrived in fishponds fed by the stream water.
Later on, in the 1870's, after the privatization of lands, dramatic changes have taken place in the area. Taro was successively replaced with sugar, rice and pineapple. Along with this, are changes in crop cultivation and agricultural practices, which characteristically result in soil erosion. More recently, residential communities replaced the agricultural fields, and, mangroves have invaded the area close to the fishpond and mouth of the stream.
The uncontrolled sedimentation and encroaching of alien vegetation (i.e. mangroves) degraded the water quality and stream flow around the He'eia shoreline and riparian zones. The "Long Bridge" that spans this area has been know for its more colorful metaphor "Stink Bridge". In 1998, the Friends of He'eia State Park started its coastal restoration project. This is what brought Windward Community College into the picture. Windward was interested to determine if the restoration project had any affect on improving the overall water quality.
Increase in population with its inherent problems of sewage and pollution is a continuing threat to the health of the environment. But, inspite of these changes, He'eia Stream remains one of the least altered of Oahu's urban streams, having only 14% of its embankment altered by man-made structures.
At present, although agriculture may not seem important to the area, it is still necessary to restore/maintain the He'eia Stream in its healthy state. Native plants and steam animals are part of the ecosystem and should be provided a healthy environment. The stream should continue to provide important nutrients to the estuary.
All monitoring of chemical parameters such as nitrite and nitrate amounts where conducted by students of Windward Community College. The monitoring of physical parameters such as water flow rate, temperature, pH were conducted by students of the Hawaii Pacific University.