Some Suggestions on Controlling Catastrophic Debris Flows on Aug. 8th,2010 in Zhouqu,Gansu

the debris flow catastrophe which broke out in Sanyanyu and Luojiayu ravines,the tributaries of Bailongjiang River,in north and east of Zhouqu,Gansu Province at midnight on August 8th,2010.is the most serious disastrous events of lives and properties losses in P.R.China.After the disasters occurred,there are ten million cubic meters solid materials in the ravines,Sanyanyu,Luojiayu and other 4 ravines also have high risk for debris flow formation in near future。 Based on studying the debris flow formation causes and hazards situation,construction distribution of the city,river bed and sand yield of Bailongjiang River,the guiding ideology and 5 prevention principles are put forward in the paper,which is to combine the engineering and biological measures,to take engineering measure as the dominant factor and to combine the regulating measures and draining measures,taking regulating measure as the dominant factor.Author thinks that the scale of debris flow on August 8th can act as the controlling standard of Sanyanyu and Luojiayu ravines,the other 4 ravines can choose frequencies of 1% as their standard.Some countermeasures such as blocked dams,embankment dams,slope stabilized dams,debris floe channel,river bed engineering works and biological measures et al are used for protecting peoples and properties in Zhouqu.At last,some controlling ideas are suggested for government and managing departments.