引洮供水一期工程为甘肃省大型长距离输水工程，为了给工程优化设计提供依据，糙率原型观测研究选择在引水流量、工程类型与引洮工程相近的引大总干渠30A隧洞和盘道岭隧洞及东二干渠U形渡槽和弧底梯形明渠进行。隧洞试验段流量与水位采用自动监测系统进行，原型观测结果为：30A隧洞预制钢筋混凝土管片衬砌圆形断面实测平均糙率0.012 627，盘道岭隧洞三心圆拱直墙平底板矩形断面实测平均糙率0.011 55；圆拱直墙反底拱断面实测平均糙率0.011 521。林坪沟钢筋混凝土U形渡槽实测平均糙率为0.011 93；林坪沟混凝土预制板衬砌弧底梯形明渠实测平均糙率为0.013 69。糙率原型观测结果均小于工程设计规范值。

In order to provide the basis for the Taohe River Water Transfer First- phase Project which is large transfer project of Gansu Province, the prototype observation research of roughness coefficient was done at 30A Tunnel, Pandaoling Tunnel, trapezoidal open channel and u-shaped aqueduct which are separately located in main channel and East Secondary Channel of the Dahe River Water Transfer Project analogous to the former project. The discharge and water level of tunnels were monitored automatically. The observed results are as follows: The average roughness value of 30A Round Tunnel with precast reinforced concrete segment lining is 0.012 627; Pandaoling Tunnel with three-centered circular arch , vertical wall and flat bottom floor is 0.011 55, while with circular arch , vertical wall and inverted arch bottom floor is 0.011 521；Linpinggou U-shaped Aqueduct of reinforced concrete is 0.011 93；Linpinggou Open Channel with concrete prefabricated panel lining and arc bottom trapezoid section is 0.01369. All these measured values are lower than the specification regulated values. This is the second part of the research.