This report describes the experimental results and the discussions on the hydraulic behavior of a flow with very mild hydraulic gradient in smooth open channels.
The following results were obtained from these investigations ;
1. Practical instruction on the resistance coefficient of flow is given by the measurement of the friction velocity of flow.
2. The velocity distribution of flow is nearly comformed to logarithmic law by the investigation of characters. and the following discussion is given on the constants A_s and B_s which contained logarithmic distribution formula.
3. The instruction of practical hydraulic computation is given by the correction of MANNlNG'S roughness coefficient.
4. The practicability of these results were proved from the survey of the natural drainage river.