ROAD-RELATED MASS MOVEMENT IN WEATHERED GRANITE, GOLDEN DOWNS AND MOTUEKA FORESTS, NEW ZEALAND: A NOTE

Four major storms in July and August 1990 triggered 263 failures on the cutbanks and sidecast of 142 km of access roads in the granite terrain of Golden Downs and Motueka forests. The total volume of material displaced over the 209-km road network in granite was estimated at 193,000 m³, which is about 367,000 t or approximately 2,800 t km⁻². This is equivalent to 80 years of sediment yield from surface erosion (estimated at 37 t km⁻²yr⁻¹ from the same road network in an earlier study).