| Title |
Optimization for Roughness Coefficient of River in Korea - Review of Application and Han River Project Water Elevation - |
| Keywords |
roughness coefficient;FLDWAV;HEC-RAS;diameter of bed material;evaluation of levee safety;조도계수;FLDWAV 모형;HEC-RAS 모형;하상토 입경;계획홍수위 검토 |
| Abstract |
Manning"s roughness coefficients were reevaluated for the computation of river flow of the Han River, the Nakdong River and the Geum River. The roughness coefficients were estimated by two methods. One is based on the assumption that rough-ness is primarily a function of grain diameter and the other is based on the findings that roughness may vary significantly with the flow discharge. The roughness coefficients adopted in each river improvement master plan have been compared with those obtained using the FLDWAV in this study, and their applicabilities have been reviewed, using the FLDWAV and HEC-RAS models. The design flood water levels computed by the abovementioned models with the roughness coefficients proposed in this study have shown good agreement with the measurements of time variation. The roughness coefficients computed using the FLDWAV model showed nearly no close correlation with the various hydraulic characteristic factors, such as grain size and river depth, etc.. Finally the design flood water levels and levee safety about the downstream part from the Paldang Dam of the Han River has been reviewed using HEC-2 model with roughness coefficients of this study and the results indicated that some parts of the existing levees were short of safety. |