长江上游泥石流重度危险区

CATASTROPHIC DANGER DISTRICT OF DEBRIS FLOW IN THE UPPER REACHES OF CHANGJIANG RIVER

本区泥石流危害严重，泥石流自然危险度指标级别主要为Ｂ级．泥石流沟密度大，泥石流暴发频繁，人为泥石流众多．泥石流沟多处于活跃期或发展期．泥石流的防治原则是全面防治、重点治理，生物措施和工程措施相结合，行政法令和宣传教育相结合．

Debris flow harms the people’s lifes and property seriously,or has the powerful capability ofinjury in the eatastrophic danger district of debris flow in the upper reaches of Changjiang River. The firming conditions , activity characteristics and developmentaI tendency of debris flow in thedestrict are discusscd, the status quo of debris flow prevention is summed up,and Some principlesand suggestions of debris flow prevention are put forward.The natural danger degrees are B which is favourable to the intense activity of debris flow inmost part , A which is favourable to most intense activity of debris flow in a little part and Cwhich is favourable to medium- intensitied activity of debris flow in little part of the district.The characteristics of debris flow in the district are:the debris flow gullies are dense,thefrequency of debris flow is high,and there are many debris flows caused bv human unreasonableactivitis.Dedbris flow is in or developing period for the favourable natural environment.The principles of debris flow prevention in the district are as follows:1)to take controllingthe important gullies as the key link and ensure an all round prevention;2)to combif1e civil engi- neering with biologic engineering;3)to combine the administrative decrees with the propaganda.