Highlights of the ceremony included historical presentations, proclamations from the City and County of Honolulu and the state House of Representatives, and testimonials from the engineers and city officials who helped conceive, design and build the Windward O'ahu project at the foot of the Ko'olau Mountains.

John Pelowski, the Honolulu District's former chief of planning and technical supervisor during construction, said the project was conceived by former Honolulu Mayor Frank Fasi and his administration as a way to protect the Kane'ohe-Kailua area after massive floods in the 1960s caused significant damage to homes and loss of life in the area.

"The city reached out to the Corps to develop a joint federal/city cost-sharing flood-control project," Pelowski said.

The project was authorized under the Flood Control Act of 1970.

According to Lester Chang, director of the city Department of Parks and Recreation, the Corps pulled it all together and created a unique project that creatively combined flood control and recreational features.

After extensive research and coordination with the City and County of Honolulu and numerous state and federal agencies, the Corps began construction of an earthen dam and recreation area in April 1976, said Honolulu District Commander Lt. Col. Charles H. Klinge.

"The contractors during construction were a joint venture of local contractor E. E. Black and S. J. Groves of Minneapolis," Klinge said.

After years of challenging construction in a rain forest environment that averages 80 -100 inches of rain a year, the Corps finished the dam and Ho'omaluhia Recreation Area in 1981 at a cost of a little over $29 million.

Flood control features cost approximately $17 million, and the rest was spent to create the park and recreation facilities.

The result was Ho'omaluhia ("place of peace") Botanical Gardens, which covers over 400 acres, includes a 32-acre lake, and is home to endangered birds (including the Hawaiian coot) and a botanical garden featuring rare plants from the Islands, Polynesia, Africa, South Asia, Melanesia and tropical America.

The garden opened to the public in March 1982.

Over 100,000 people visit Ho'omaluhia every year to hold meetings, hike, camp, picnic, fish, bird-watch and more. There is a visitors center, and a small art gallery where local artists display their work.

"Ho'omaluhia is one of the nicest and most beautiful recreation areas I've ever seen," Klinge said. "This project is a clear demonstration of the Corps' commitment to our Environmental Operating Principles, it protects lives and promotes the economic well-being of the windward side of O'ahu, and it provides a tremendous place for visitors to take in the splendor of the Ko'olau Range."

The dam has prevented an estimated total of almost $18 million in flood damage in the last quarter centur, according to Jim Pennaz, Honolulu District Civil Works Technical Branch chief, who served as the project's hydraulic engineer.

In particular, it prevented $1.5 million worth of damage in March 1980 and $8.7 million during storms from 1987 to 1996. In 2005, the dam prevented almost $1.5 million worth of damage, according to Pennaz.

City Parks Director Chang read and presented a City and County of Honolulu proclamation on behalf of Mayor Mufi Hannemann to Ho'omaluhia Program Coordinator Olive Vanselow and Ho'omaluhia staff and volunteers.

Honolulu Botanical Gardens director Winnie Singeo served as the master of ceremonies.