Response to Landslide Dam Failure Emergencies: Issues Resulting from the October 1999 Mount Adams Landslide and Dam-Break Flood in the Poerua River, Westland, New Zealand

Abstract

On October 6, 1999, a large rock avalanche from Mount Adams on the west coast (Westland) of the South Island, New Zealand, fell into the Poerua Valley. The landslide blocked the river valley, damming the Poerua River, and creating a large lake. The potential for overtopping and failure of the landslide dam presented a potential dam-break flood hazard that was assessed as posing a serious danger to Poerua Valley residents located downstream. The dam eventually failed