Lessons learned from protective measures associated with the 2010 Zhouqu debris flow disaster in China

On August 7 and 8, 2010, a catastrophic debris flow disaster occurred in Zhouqu County in northwestern China’s Gansu Province. The large-scale debris flow event destroyed more than 200 buildings, killing approximately 1,700 people. Field investigations showed that the debris flow disaster was not only a natural hazard but also anthropogenic. First, the partial implemented check dams had not formed an integral blocking system to resist large events. Second, poor-quality workmanship contributed to the breakage of check dams. Third, disorderly placement of houses and buildings on the fan structure rendered the cross-sectional area of drainage channel too small to accommodate such a large event. The lessons learned from these hazards may be valuable for improving protective measures against these types of very large debris flow events in northwestern China in the future.