豪雨期間魚塭排水特性之研究及其對區域排水系統之影響評估

Abstract

臺灣位處於西太平洋颱風路徑影響範圍，經常遭受颱風及西南氣流所產生之豪大雨的威脅，若颱風豪雨期間遇上漲潮時段，容易形成海水倒灌造成更嚴重的災害。魚塭被認定為具有滯洪的特性，可是對於其較為詳細的研究資料卻不充足，本研究目的是調查及分析魚塭之排水特性，並利用颱風來臨前之時間，套用氣象局預測之降雨量、當地雨型及潮位，分析魚塭排水對排水系統之影響。在屏東，多為初始水深1.5m的魚塭(總高3m)，水體體積大，不需考慮鹽度條件，只需考慮防止溢堤的狀況，嘉義實驗區養殖池初始水深平均約為1m，堤頂高約1.7m，可容忍之降雨水深約0.2m，排洪時需考慮鹽度變化。調節排水時間達到最大滯洪效果，計算養殖池需預留的深度，在洪鋒來臨前預先排水，保留養殖池容量，增加滯洪效果。建議建立中央抽水系統，關閉防潮閘門，可降低潮汐影響，另外抽排用水取自同一水路，不能確保水質。實驗區建立中央海水供應系統供沿海魚塭利用，好處有二，第一，魚塭不需抽取排水路之漲潮水，防潮閘門可確實關閉，降低排水系統水位；第二，同一排水路不應用作取水和排水，容易交叉污染，若建立中央海水供應系統，取水可作水質處理及檢驗，可確保水質。

Taiwan is frequently hit by typhoons and the southwest air current. It generated heavy rain. If rain during the high tide period, easy to form water intrusion or caused serious disaster especially in low-lying coastal areas. Fish ponds were identified as having the characteristics of flood protection, but for the more detailed research data is not much. Using the local rainfall pattern and tide, analyze the impact of derivation of the pond drainage on the drainage system. In Pingtung, the initial depth of 1.5m over the fish ponds (total 3 meters high), a large volume of water, irrespective of salinity just consider the situation to prevent overflow, the Chiayi area ponds initial average depth is about 1 meter and the dam high about 1.7 meters. The capacity of depth is about 0.2 meters; drainage should be considered when the salinity change. According to the maximum flow time adjusting drainage time, calculate the depth of ponds to be reserved in advance before the arrival of the maximum flow, retention ponds capacity, and increase flood detention effect. Proposed establishment of a central pumping system, the benefits of two points, first, close the downstream floodgate can reduce the tidal effects. Second, the drainage water easy to cross-contamination, if the establishment of a central water supply system, water can be used for water treatment and testing, to ensure water quality.