Abstract: The roughness of a large water transfer project is one of the important parameters at engineering design stage. With the development of construction technology, measured roughness values are lower than regulation values in specification . But there is no reliable basis to reduce the roughness values. In order to provide the basis for the Taohe River Water Transfer Project, the Water Resources and Hydropower Development Co. Ltd of Gansu Province established an item to conduct the prototype observation research in 2006, which was selected at main channel and east secondary channel of the Dahe River Water Transfer Project constructed in 1995.The discharge of tunnels was monitored automatically by the swing  shape flumes which were built at the outlet of 30A Tunnel and the entrance of Pandaoling Tunnel respectively, and the water level was observed simultaneously through 6 survey sections. The observations were manually carried out at the 2 open channels. This is the first part of the research.