| Title |
Analysis of Roughness Coefficient in Gravel-bed Rivers |
| Keywords |
roughness coefficient;gravel-bed river;bed-material;relative smoothness;조도계수;자갈하천;하상재료;상대수심 |
| Abstract |
The purpose of this study is to analyse characteristics of roughness coefficient based on bed-material size of the gravel-bed rivers using field data obtained from nine domestic rivers. Roughness coefficient is calculated using Manning"s equation. Roughness coefficient decreases with increasing discharge, but above a certain discharge, it tends to be constant. Similarly, roughness coefficient shows reverse relationship with relative smoothness (R/D). The regression equation adopting theoretically derived value of 2.03 as log coefficient indicates close similarity with the previous equation proposed by Limerinos (1970). Roughness coefficient values converged above certain discharges lie in the range from 0.024 to 0.045. From them, empirical equations based only on bed-material size are derived and compared with those suggested by the previous studies. |