大型长距离输水工程的糙率是工程设计中的关键参数，随着工程施工技术的进步，工程建成后的实际糙率小于规范值，但设计中如何减小糙率取值则无选择的依据。为了给引洮供水工程优化设计提供依据，甘肃省引洮水利水电有限责任公司于 2006 年立项进行糙率原型观测研究，原型试验工程选择 1995 年建成的甘肃引大灌区总干渠和东二干渠，原型观测隧洞试验段分别在 30 A 隧洞出口与盘道岭隧洞进口修建机翼形量水槽，采用自动监测系统实时监测流量，隧洞水位各设 6 个观测断面，并采用水位自动监测系统实时监测。两处明渠段糙率原型观测试验水位流量采用人工方式进行。本文为该项研究的第一部分。

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.