Keopu Flood Control Study

Oceanit evaluated the flooding problem in Kailua-Kona, and over several years conducted a flood control study of the Keopu-Hienaloli streams responsible.

Oceanit evaluated the flooding problem in Kailua-Kona, and over several years conducted a flood control study of the Keopu-Hienaloli streams responsible.

Kailua-Kona is located on the slope of Hualalai volcano on the Big Island of Hawaii, and the steep slopes result in major flooding of the town during heavy storms. Oceanit was selected by the Army Corps of Engineers and the Department of Public Works to provide engineering and environmental consulting services to evaluate the flooding problem, and to conduct a flood control study of the Keopu-Hienaloli streams that cause the flooding in Kailua-Kona.

Oceanit provided long-term engineering and environmental consulting services to evaluate the flooding problem and to conduct a flood control study of the Keopu-Hienaloli streams that were the cause of the flooding. We assisted the COE to develop the scope of work. We conducted topographic surveys, LiDAR and aerial surveys, archaeological studies, flora and fauna studies, and socioeconomic studies to prepare a complete Environmental Assessment (EA). We prepared the EA to assess the environmental impacts of implementing the recommended flood control measures within the project area. We provided detailed analysis of a recommended plan, alternatives, and modifications. Engineering and design data were provided to enable further refinement of project flood control improvements, including preliminary design. A baseline cost feasibility study report for implementing flood control improvements in the Keopu-Hienaloli Watershed project area was prepared: the economic analysis that showed two of the four alternatives considered would provide positive net annual benefits and Benefit to Cost Ratios greater than 1. Proposed improvements under these alternatives would contribute positively to the National Economic Development objective of improving the net productivity of flood-prone land areas. Project benefits were quantified in terms of reductions in flood damage costs to residential, commercial and public structures, property contents, vehicles, outdoor property and corresponding reductions in emergency clean-up, travel delay and road repair cost. A preliminary design of the flood control improvements and estimated construction costs for the four alternatives was also provided.

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