滯洪池濕地生態功能評價指數建立及應用

Index of Wetland Condition Development and Application for Evaluating Ecological Functions of Detention Ponds

施上粟(Shang-Shu Shih) ； 黃國文(Gwo-Wen Hwang) ； 黃志偉(Ji-Wei Huang) ； 洪崇航(Chung-Hang Hong) ； 任秀慧(Rita S. W. Yam)

《農業工程學報》 62卷3期 (2016/09) Pp. 1-12

https://doi.org/10.29974/JTAE.201609_62(3).0001

摘要

滯洪池除可調蓄洪水、降低洪峰、降低水患衝擊及沉澱泥沙等防洪減災功能外，在景觀美化、休閒遊憩及生態環境改善上亦具相當價值。本研究主要目的在探討及分析現有滯洪池的濕地生態功能，並進一步分析生態功能與防洪需求之競合關係，提出滯洪池濕地生態功能改善策略及配合措施。本研究提出濕地狀況指數(IWC)進行滯洪濕地生態功能的評價，並選擇以下四處滯洪池進行IWC 的評價應用：1.臺北市大溝溪滯洪池 + 大湖滯洪池；2.嘉義縣新塭滯洪池南池 + 北池。IWC 評價結果表明，水域動物及濱溪植物覆蓋度是比較弱的項目，水域動物分數與外來種及滯洪池底部封底有關，建議應適時移除外來種，並禁止民眾任意放養。雖然都市化地區的滯洪池易受週圍環境及人類活動影響導致棲地品質劣化，但在環境劣化或棲地破碎化的都市化地區中，鳥類等野生動物選擇變少，滯洪池仍扮演重要生物庇護所及生態廊道、生態跳島的重要角色，故永續的滯洪池生態管理必需同時兼顧滯洪池本體，及週邊土地及相關人類活動的特性，透過適當的設計，滯洪濕地有機會同時滿足防洪及生態保育的需求。

關鍵字

滯洪池 ； 濕地 ； 生態功能 ； 濕地狀況指數

並列摘要

Detention ponds are engineered facilities for flood detention with the primary purposes to reduce the peak discharge and delay the arrival time of flood peaks during the flood period. The detention wetland (DW) is defined as a composite facility combining detention pond and free water surface (FWS) wetland, designed to serve as ecological functions, such as wastewater treatment and wildlife habitats, in addition to its flood detention function. This study aims to evaluate the ecological function of DW and provide improvement strategy according to the field survey, model simulation and wetland scores calculation. The ecological investigations were conducted every season during the project executing. Both biotic and abiotic items were included. They are benthos, vegetation, birds, fish as biotic items and water quality, water surface elevation, water connectivity and bank erosion by wind-induced wave propagation representing abiotic factors. We also established a new model named as index of wetland condition (IWC), to quantify the ecological importance of DW based on a scoring system. The IWC consists of five subindices, such as hydrology (HY), water quality (WQ), physical environment (PF), riparian vegetation (SID), and aquatic animal (BI). Four DWs including Dago pond (DG) and Dahu pond (DH) in Taipei City and Hsinwen-south pond (HS) and Hsinwen- north pond (HN) in Chiayi County were selected as our study sites to evaluate ecological functions of DW systems in urban areas. The IWC scores for DG, DH, HS and HN were 76, 70, 74 and 74 respectively, and this indicated that all study DW sites were able to provide marginal to good ecological functions. Possible methods and techniques for enhancing the ecological functions of DW systems were also suggested and discussed to provide insights on management strategies for DW in Taiwan.

並列關鍵字

Detention pond ； Detention wetland ； IWC ； Ecological function