Method of field survey for debris flow is classified into two types:regional survey and gully investigation.Two methods are systematically discussed.Regional survey is main to collect and analyze the background material of the formation and active area of debris flow
then to disting uish the debris flow gullies.The gully investigation is main on the landforms
geologic structure
weather and hydrology
etc.of some specific debris flow gully
there form to determine the different indices needed by the control engineering design of debris flow.