考量水量水質與棲地指標之最佳工程規劃研究-以社子島濕地為例

濕地作為地球上生產力最豐富的生態系之一，提供許多生物繁衍和棲息的重要環境，然而在過去一個世紀裡，受人類活動影響，全球超過50％的濕地喪失，剩下的濕地也發生不同程度的退化，在當今氣候變遷及環保意識抬頭的條件下，為了彌補過去開發行為所破壞的濕地以及避免更多濕地因人為開發而消失，都市內人工濕地的營造已受到國際間的重視，惟這些人工濕地的營造多以蓄滯洪流與污染物為主要目的，對生態方面考量並不夠完善，儘管這些人工濕地亦具有部分生態功能，然而長期接收都市排水與汙染物會導致其功能愈發劣化，這使其在上述環境背景下仍面臨縮減退化的可能，因此如何適當經營管理綜合功能之人工濕地成為現今重要課題。本研究之研究區域為社子島濕地，其經由既有舊防潮堤水門與基隆河連通，其水體之變動主要受基隆河潮水影響，為了透過工程手段使社子島濕地之功能最佳化，本研究將社子島濕地既有舊防潮堤水門作為基礎，探討不同水門數量對濕地功能之影響，其中包括生態、水質以及滯洪，並透過荷蘭Delft水利研究院Delft3D Flexible Mesh數值模型，採用各潮水位情境下之水理與水質條件，並參考濕地狀況指標(Index of Wetland Condition, IWC)之評分方式，嘗試以現有指標量化方式快速評估濕地之優劣，生態方面，選用小水鴨、小環頸鴴、小白鷺以及田鷸為目標物種，以水深與鹽度評估棲地適合度指標(Habitat Suitability Index, HSI)，水質方面採用成功大學溫清光教授為台灣河川研發本土化之河川水質指標(Water Quality Index, WQI)，水文滯留足跡(Hydrologic footprint residence, HFR)則代表滯洪功能，最後將各指標利用最大絕對值正規化使其一致並給予不同程度之加權，找出基於上述三種指標之最佳化濕地。結果顯示在綜合潮位評估後，共有4851種組合，其中有2836種最佳配置為兩個水門，佔整體百分比58.46％，可得出在兩個水門配置下，能兼顧濕地生態、水質與滯洪功能，在得出此結果後，本研究進一步將兩個水門配置中第二個水門位置變更，測試其在上游、中游以及下游位置下各指標變動情形，其中上游為本研究兩個水門配置之初始位置，綜合潮位評估後有4831種最佳配置為兩個水門上游，佔整體百分比99.59％，顯示依舊以本研究初始設置之兩個水門配置位置為優，期許未來能將此設計想法運用在營造人工濕地時的一種評估方式，使工程能兼顧經濟與生態環境，以達到全世界永續發展之目標。

關鍵字

人工濕地；濕地狀況指標；棲地適合度指標；河川水質指標；文滯留足跡

並列摘要

As one of the most productive ecosystems on earth, wetlands provide an important environment for the reproduction and habitation of many organisms. However, in the past century, due to human activities, more than 50% of the world's wetlands have been lost, and the remaining wetlands degradation has also occurred to varying degrees. Under the conditions of today's climate change and environmental protection awareness, in order to make up for the wetlands damaged by past development behavior and prevent more wetlands from disappearing due to human development, the construction of artificial wetlands in cities has become an important issue. International attention has been paid to these constructed wetlands, but the main purpose of these constructed wetlands is to store torrents and pollutants, and the ecological considerations are not perfect. Although these constructed wetlands also have some ecological functions, they have long received urban drainage and pollution. Therefore, how to properly manage constructed wetlands with comprehensive functions has become an important issue today. The research area of this study is the Shezidao Wetland, which is connected to the Keelung River through the existing tidal levee water gate. The changes of the water body are mainly affected by the tide of the Keelung River. In order to optimize the function of the Shezidao Wetland through engineering methods change, based on the existing tide-breakwater gates in Shezidao Wetland, this study explores the impact of different numbers of gates on wetland functions, including ecology, water quality, and flood retention, and referring to the scoring method of the Index of Wetland Condition (IWC), try to use the existing index quantitative method to quickly evaluate the pros and cons of wetlands. Green-winged Teal, Little Ringed Plover, Little Egret and Common Snipe are the target species, and the Habitat Suitability Index (HSI) is evaluated by water depth and salinity. In terms of water quality, Professor Wen of Cheng Kung University is used to develop The Water Quality Index (WQI) for Taiwan's rivers. The hydrological footprint residence (HFR) represent the flood retention function. Finally, each index is normalized by the maximum absolute value to make it consistent and weighted to different degrees. then find the optimal wetlands based on the above three indicators. The results show that there are a total of 4851 combinations, of which 2836 are optimally configured with two water gates, accounting for 58.46% of the total, it can be concluded that under the configuration of the two water gates, the wetland ecology, water quality and flood retention functions can be taken into account. After getting this result, the position of the second water gate in the two water gate configurations was further changed, and the changes of each index in the upstream, midstream and downstream positions were tested, also the upstream design was the initial position of the two water gate configurations in this study. After the comprehensive assessment, there were 4831 The optimal configuration is the upstream design of the two water gates, accounting for 99.59% of the overall percentage, which shows that the initial configuration of the two water gates in this study is still the best. It is hoped that this design idea can be used as an evaluation method when constructing constructed wetlands in the future, so that the project can take into account the economic and ecological environment, in order to achieve the goal of sustainable development in the world.