FEATURES AND PREVENTIVE COUNTERMEASURES OF DEBRIS FLOW IN A MOUNTAINOUS SCENIC SPOT,TAIZHOU COUNTY,ZHEJINAG PROVINCE

A scenic spot in Taizhou, Zhejiang province locates in a mountainous area, the terrain changes sharply, and thus many cliffs stand steeply. According to the field research, there are 8 debris flow gullies lay along a stream flowing in northwestern direction. Although small in size, the longitudinal gradients of these gullies are 485~864,which accumulate potential energy for the outbreak of debris flows. A rainstorm on July, 5, 2017 triggered debris flows in these 8 gullies, 7 of which carried debris, piled up and blocked the tour road. Large amount of debris of No.8 gully rushed in the ticket office, causing a serious loss to the scenic spot. In this paper, a detailed field study was carried out on these gullies, and analyzed the features of them and conditions that would trigger debris flows in these gullies. Taking debris flow in No.8 gully for example, many characteristic parameters of which were calculated, such as the bulk density, density, volume of debris for once outbreak, total volume of debris for once outbreak, etc. Based on these parameters, this paper put forward some preventive countermeasures, which could be a reference to the prevention of other debris flows near this scenic spot.