圖書典藏及影音數位平台

河川治理工作對於深槽演變尺度之探討極為重要性，不僅止於在決定通洪能力之思維，故如何使水量與泥砂維持長期動態平衡，為目前河川治理規劃頗具挑戰性之課題；實務上，河川治理法線係考量既有或計畫待建河防建造物、計畫洪水位到達範圍及沿岸保護標的等據以訂定高水治理下之計畫河寬，有待進一步探討河川深槽各種尺度演變對於既有河川治理法線之影響。河川治理之工程措施需考量河相與河性，因地制宜，達成減災並兼顧生態需求及環境品質提升。工程實施需瞭解河川不同時間、空間尺度之物理特性，純以洪水位探討堤頂高不足之高水治理思維，無法根本解決土砂不平衡之沖淤問題，亦無法減少流速、流向造成河防設施之破壞，間接影響高水治理之效果。故藉由深槽水理特性分析與應用，河川有效因勢利導，進一步完成防洪減災之目標。

The understanding of the characteristics of river main channel meandering is important for the watershed management. This study conducted Odgaard and Ikeda’s river meandering theories to estimate the channel stability and meandering procedure to facilitate the river restoration. In order to conduct the wavelength to maintain the channel stability the information should include the river type discriminant, river characteristics analysis and calculation of river stability conditions. The Beigang River was selected as the major study site. The Gaoping River, on the other habd, was the secondary study site to evaluate the cabapiliby od meandering theries for Taiwan. Firstly, this project collects the basic data of the river and the literature review on main channel migration theories and methods. The time scale for river migration studies was focused on the decades or centuries. However, the effect of climate change becomes the important role and the storm event is more frequent which might shorten the time scale of main channel migration. The project, therefore, plans to establish a mesoscale time scale (20 years) for river migration study. The satellite images and aerial photos were conducted to analyze the channel wavelength ( ) for 10 years. Then, the cross-section measurement data and hydrological data were applied as the numerical model of the initial river bed conditions. The historical measurement was used to qualitatively and quantitatively understand Beigang river migration. Moreover, those were also combined with the multi-model and ensemble forecast for the numerical verification. To build a bed evolution model which can effectively reflect the main channel migration behavior and to analyze the horizontal and vertical changes of the river. The results of the satellite and the numerical model could be input to the main channel meandering theory and calibrated the value in the different river reach. The designed scenarios could be simulated to obtain the future wavelength and further evaluated the variation of the wavelength. Finally, the latest annual satellite imagery and cross-section measurement data were conducted to simulate the future scenarios and estimate the possible migration behavior of the main channel. The result is able to analyze the disaster potential. It can help us to set the river restoration under appropriate countermeasures In the recent periods, the computing efficiency improves due to the technological development, the concept of the multi-model system combined the ensemble forecast should be introduced to determine the value, and applicable to a specific watershed, which can be used to assess possible damages during flood periods. The framework of the main channel meandering theory proposed in this project can quickly obtain high-potential areas for each river reach. It is necessary to evaluate the feasibility of applying the main channel meandering theory to other river basins in the future, thereby completing the disaster potential maps in Taiwan.