新北濕地小水鴨棲地保育與防洪需求競合探討

Evaluating the Competition and Cooperation between Waterbirds Habitat Conservation of Hsinpei Wetland and Flood Control Demand

施上粟(Shang-Shu Shih) ； 陳炳宏(Ping-Hung Chen) ； 李孟穎(Meng-Ying Lee) ； 歐陽慧濤(Huei-Tau Ouyang)

《農業工程學報》 62卷1期 (2016/03) Pp. 1-11

https://doi.org/10.29974/JTAE.201603_62(1).0001

摘要

新北溼地位於淡水河左岸、二重疏洪道入口堰外，與對岸華江溼地均位處大漢溪、新店溪匯入淡水河，一般統稱「江子翠」，每年秋天至隔年春天間吸引小水鴨等雁鴨至此造訪。近年濕地有明顯的陸化現象，造成小水鴨喜好之棲地條件逐年劣化，同時也影響二重疏洪道入口堰的分洪能力，進一步弱化淡水河防洪整體功能。本文利用數值模式評估現況及8 組棲地改善方案的疏洪道分洪量及小水鴨棲地適合度，以瞭解本區防洪需求與生態保育間的競合關係；數值模式經水工模型試驗結果驗證具可信度。研究表明，丁壩導流工方案雖能提升疏洪道分洪量，但無助於小水鴨棲地的改善，兩者間無明確競爭或合作關係；疏濬方案則發現分洪量與小水鴨棲地適合度均提高，顯示兩者間具「合作」關係，其中具最佳改善效益的Scenario 1-2為建議方案。此研究案例顯示防洪與生態保育間有合作空間，可作為類似之都市型河川，在進行河川環境規劃、營造及管理時的參考。

關鍵字

新北溼地 ； 二重疏洪道 ； 小水鴨 ； 棲地適合度 ； 分洪量

並列摘要

Hsinbei and Huajiang wetlands, located at the confluence of Dahan Creek and Xindian Creek, attract thousands of ducks to visit during September to next April every year. In recent years, the wetlands have been led to a significant terrestrial due to sediment deposition, resulting in a reduction of teals since their habitat preferences could have been negatively affected. The effect also influences the flood diversion of the Erchung Floodway and might increase flood level of the Tanshui River. The horizontal two dimensional model, TABS-2, was employed to simulate the flow condition and to calculate the bypass flow discharge. The habitat suitability index of common teals was used to evaluate the ecological scores. A total of eight sets of simulated scenarios in three categories were designed to compare with the current situation, i.e. ＂No action＂. In category (1), the bypass flow discharge of Scenario 1-1 is slightly greater than that of Scenario 1-2; however, the excavation volume is far greater than that of Scenario 1-2. In light of marginal benefits, Scenario 1-2 should be adopted for this category. In category (2), the bypass flow discharge of Scenario 2-1 is the greatest, followed closely by Scenario 2-2 while that of Scenario 2-3 is the smallest. In category (3), groins are set up across from the Sanchong trash mountain and at the right bank where the Dahan River merges with the Tanshui River. Although the groins raised the bypass flow discharge, they had poor ecological performance. The excavation Scenario 1-2 has the best efficiency and indicates a cooperation relationship between flood control demand and ecological conservation. Our study suggests a practical reference for initialing or revising a river planning of an urban river.

並列關鍵字

Common teals ； Habitat suitability ； Erchung Floodway ； Flood bypass