City stitchesBy Gordon Y.K. Pang
Manoa slope to
Landslide stabilization work has been completed at or around 175 east Manoa homes, city officials have announced.
The $23 million project was undertaken to stop landslides that threatened to destroy homes and property in the area since 1989.
Mayor Jeremy Harris and area Councilman Andy Mirikitani hailed the technology as innovative and a model for other areas on Oahu vulnerable to landslides.
Concrete tieback anchor systems were installed to stabilize the sliding hillside.
"It's kind of like stitching the hillside," said Roland Libby, the city's deputy director of design and construction. "They're drilling down and grabbing the lowest stable section going down into bedrock and then tying that to the ground surface."
Grout is poured into the drilled areas to form a dumbbell shape designed to prevent the soil from shifting.
A vertical drainage system was also put in to relieve groundwater pressure, a primary cause for the landslides.
Improvements were also made to water and sewer lines, drainage systems and roads.
Libby said a similar project is under way in Moanalua, and other landslide-prone areas "can potentially be treated in the same way."
Mirikitani, who helped secure funding, said that had the project not begun quickly, "the entire eastern valley and homes below would have been endangered."