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Kolea and Wahikuli Dam Removal

In summary, Oceanit provided the State of Hawaii Department of Accounting and General Services (DAGS) and Department of Land and Natural Resources (DLNR) with engineering and environmental services for the removal of two state-owned dams on Maui.

The State of Hawaii owned two dams on Maui which were regulated, but had no economic or useful functions. Removal of dams is a complex problem in every situation because of the possible cultural, archaeological, biological, and other environmental impacts. The design must be customized to account for impacts to the community and environment.

Oceanit engineered breaches to the dams to minimize impact to the environment and blend with the existing biota and hydrology. The work was carefully and meticulously coordinated with regulators such as the U.S. Army Corps of Engineers, State Department of Health, Department of Land and Natural Resources (DLNR), and county agencies.

Wahikuli Reservoir (MA-0055) was under the regulatory jurisdiction of the DLNR Dam Safety Office. A Phase I Dam Inspection Report assessed the structure to be in “poor condition”, and classified the resevior as a high hazard structure. The State and other stakeholders determined that dam removal was the best option. The project conducted engineering studies and assessments; prepared contract documents, including plans, specifications, and cost estimates; secured all necessary permits; and provided post-design services for the removal of Wahikuli Reservoir (MA-0055) near Lahaina, Maui.

Kolea Reservoir (MA-0097) was an in-stream reservoir over 100 years old that was impounding Kolea Stream. It was under the regulatory jurisdiction of the DLNR Dam Safety Office and a Phase I Dam Inspection Report assessed the structure to be in “poor condition.” The dam removal was designed to minimize the impact on the environment. The overall result of the dam removal and stream restoration removed the hazard of dam water impoundment, allow eda natural flow, provided a means to reduce sediment transport, and restored the stream’s local ecosystem. The restored channel is considered transitional and will be allowed to re-vegetate without significant interference to return to the ambient natural condition.