Review on Application of Wave Model for Calculation of Freeboard in Hydraulic Structure

J. Ocean Eng. Technol. 2007;21(1):25-30.

Kim, Kyoung-Ho;Lee, Ho-Jin;

Dept. of Civil Engineering, Chungbuk National University;Dept. of Civil Engineering, Chungbuk National University;

수공구조물 여유고 산정을 위한 파랑모형의 적용성 검토

김경호;이호진;

충북대학교 토목공학과;충북대학교 토목공학과;

Keywords: Wave model, Freeboard, Hydraulic structure, Dam, Reservoir, SWAN(Simulating wave nearshore) model, Empirical formula

핵심용어: 파랑모형, 여유고, 수공구조물, 댐, 저수지, SWAN 모형, 경험공식

Abstract

Most of dams and reservoirs were made from natural materials, such as soil, sand and gravel. This type of hydraulic structure has the danger of collapse by overflow during a flood. Freeboard is the vertical distance between the crest of the dam and the full supply level in the reservoir. It must be sufficient to prevent overtopping from over flow. Thus, freeboard determination involves engineering judgment, statistical analysis, and consideration of the damage that would result from the overtopping of a hydraulic structure. This study attempts to calculate the wave height in dam, which is needed for the determination of the freeboard of the dam. Chung-ju dam is selected as the study area. Using the empirical formulas, the wave heights in dam were calculated, and the results were compared with those by the SWAN model, which is a typical wave model. The difference between the calculated results from the empirical formulas and those by the SWAN model is considerably large. This is because empirical equations consider only fetch or fetch and wind velocity, while the SWAN model considers depth and topography data as well.