| 摘要: | 早期台灣對於河川主要是以防洪築堤為主，近幾年已將生態工程及綠美化納入其考量。河川整治不僅只考慮人類生命財產安全，還要顧及大自然的環境保護和生態保育。若建置之前未考量到河川生物的生活習性與需求，勢必會因為人類的方便而使得原有的豐富棲地環境及生物多樣性受到影響，因此本研究便探討水工結構物對於河川生物棲地環境影響。 本研究以台中市筏子溪為例，選用台灣石?為標的魚種，利用一維水理模式(HEC-RAS)結合河川棲地二維模式(River2D)進行模擬，將丁壩、固床工各設計三種尺寸分別為：短丁壩(20m)、中丁壩(30m)、長丁壩(40m)、固床工(1m)、固床工(1.25m)以及固床工(1.5m)。將水工結構物分別建置於河道，以24組流量進行模擬，探討棲地可使用面積。 台灣石?在流量Q=4.6cms~130cms 時，加入丁壩之河道的WUA 值與原始河段很接近；Q=160cms~590cms 時，加入丁壩之河道的WUA 值明顯比原始河段低很多。台灣石?在流量Q=4.6cms~220cms 時，固床工河段之WUA 值明顯比原始河段高，Q=238cms~590cms 時，固床工河段之WUA 值與原始河段之WUA 值差異不大。結果顯示，台灣石?於低流量時，固床工的設置對棲地有正面的影響；丁壩部份，不論是短丁壩、中丁壩還是長丁壩，WUA 值在高流量時明顯比原始河道以及固床工河道還要來得低。 判定標準分為：5%、3%及1.5%，對丁壩而言，判定標準越小影響範圍越大，且丁壩長度越長，影響範圍相對更遠；對固床工而言，三種判定標準顯示三種固床工之上游影響範圍已經超出研究區域60公尺，下游部分隨著判定標準越小影響範圍相對更遠。 Avoiding floods and building dikes is the main river protection policy in the early period of Taiwan. However, nowadays environment protection becomes an important issue and the Ecological Engineering Method was taken into account for the protection of river. When renovating rivers, people not only have to consider the safety and wealth of humans but also the protection of environment and ecology. Before when people renovating rivers, engineers do not consider the living creatures in rivers and their needs, it’s possible to affect the balance of ecological system and also reduce the variety of habitats. According to these reasons below, this research report is probing the positive and negative effects of the hydraulic structures to the living creatures in river. The research chose Fazih River as the study area and the acrossocheilus paradoxus as the target fish. HEC-RAS and River2D were combined to produce a simulation and to design Groundsill、Spur dike into three different sizes : short Spur dike(20m)、 medium Spur dike(30m)、long Spur dike(40m)、Groundsill(1m)、Groundsill(1.25m) and Groundsill(1.5m). The Weighted Usable Area (WUA) by making a simulation of the twenty four samples were estimated. When the flow Q=4.6cms~130cms is added, the WUA of Spur dike is very close to the original; when the flow Q=160cms~590cms, the WUA of Spur dike is lower than the WUA of original river. When the flow Q=4.6cms~220cms, the WUA of Groundsill is higher than the WUA of original river; when the flow Q=238cms~590cms, the WUA of Groundsill and the WUA of original river differences are not big. The result shows that when the flow is in the low part, the influence of the Groundsill is positive. And in the high flow section, no matter if it’s short, medium or long Spur dike, the WUA is lower than the original or groundsill one. The determined standards are 5%, 3% and 1.5%. As for the spur dike, the smaller the determination standard, the bigger the influenced area; and the longer the spur dike's length, the further the influenced area. As for groundsill, the three criteria have shown that the influences area in upstream has exceeded the studying area by 60 meters; the influenced area in downstream expands along with the reduction of critiria. |
