西子灣圍堤造地對高雄一港口進港航道影響之分析

Abstract

本研究探討高雄西子灣圍堤造地對高雄港－港口進港航道之影響。數值模擬採用MIKE21之HD（Hydrodynamic model）及EMS（Elliptic mild-slope equation）模組計算波流場，比較圍堤工程前後一港口航道漲退潮流場之差異及季節波浪與颱風作用時航道波高分佈。本研究同時於交通部港灣技術研究中心進行平面水池試驗，以試驗結果校驗數值模擬的正確性。研究結果顯示：（1）棧橋式圍堤興建對一港口航道漲退潮及轉潮之流速差異約0.01m/s，故流場可視為不變；（2）比較港內航道中心線之波場，數值模擬分析及差劣點，發現在季風波浪作用下波高最高增加4cm，颱風時波高最多增加19cm；（3）水工模型試驗結果顯示，季風波浪之波高最多增加5cm，颱風時最多增加29cm，上述差異，均在船舶進出安全容許波高40~100cm範圍；（4）模型試驗與數值模擬計算的相對波高（K（下標 D）值）相差約0.01~0.02範圍亦屬合理。This study investigates the impact of Siziwan reclamation on Kaohsiung first Harbor entrance channel. First, MIKE21's HD (Hydrodynamic model) and EMS (Elliptic mild-slop equation) are adopted to model numerically the tidal glow filed and wave height distribution induced by the seasonal wind waves and storm wave, for the scenarios prior to and the completion of the project. Scaled hydraulic model experiments were also conducted at the Harbor and Marine Technology Center in Taichung, aiming to verify the accuracy of the numerical modeling. The results derived from both numerical models and hydraulic experiments have revealed that (1) The pier-type reclamation construction could increase the tidal glow velocity by 0.01 m/s; (2) Numerical models and comparison on the wave height distribution along the center line of the entrance channel suggest the maximum probable wave height increase is about 4 cm during the seasonally wave action and around 19 cm during storm; (3) Results of hydraulic experiments suggest that wave height increase only by 5 cm during seasonally wind wave months and 29 cm during storms, which fall within the allowable wave height ranges of 40~100 cm for the safety of shipping navigation; (4) The discrepancy for the relative wave height (K(subscript D) values) between the results obtained from hydraulic experiments and numerical modeling is about 0.01~0.02, which may be considered as reasonable.