Maui County has completed a final environmental impact statement for an estimated $6 million rock revetment extension to protect the Wailuku-Kahului Wastewater Reclamation Facility and its eight underground injection wells from tsunamis.
"We need to make sure that that plant is protected," said Michael Miyamoto, deputy director of the Department of Environmental Management.
The U.S. Army Corps of Engineers recommended an extended revetment to shield the Kahului shoreline facility. Plans call for adding 1,200 feet to the west of a 450-foot rock revetment built in 1979. Additional extensions inland will be needed to prevent inundating water from "flanking" the facility.
This rock revetment on the makai side of the Wailuku-Kahului Wastewater Reclamation Facility will be raised and extended to protect the plant from tsunami inundation.
The Maui News / BRIAN PERRY photo
The crest of the new revetment will be 10 to 13 feet above sea level, according to a project description. The "toe" of the wall will be 3 feet below sea level. The top of the existing revetment will be raised to match that of the new rock wall.
The county has budgeted $6 million for the project, Miyamoto said.
To minimize erosion impacts, the extended portion of the rock wall would be buried and angled from the shoreline, he said.
Any required fill will be beach-quality sand, according to the project summary, and any additional sand will be used to cover the revetment.
For now, funding would come from the county, Miyamoto said, but the department will be seeking federal money for the project.
The project needs to acquire numerous county, state and federal permits, including a Department of Army permit, a conservation district use permit, a water quality certification, a national pollutant discharge elimination system permit, a coastal zone management consistency approval, a special management area use permit, a shoreline setback variance, a flood hazard area development permit and construction permits.
A finding of no significant environmental impact has been issued for the project.