結合UAV測繪技術於公路橋梁水情防災預警機制之研究

公路總局「公路水情防災預警機制」實施至今已有效避免人車傷亡之憾事。然而，現行防災預警機制為利用歷史致災降雨量，率定各雨量站降雨觀測指標，其不準確因素無法有效降低。本研究結合UAV測繪技術以多重尺度空間資訊將河道地形模型及水文模式整合運算，以輸入降雨量之方式預估所選定之河川斷面未來水位高程，藉此預測橋梁所在河道斷面之水位，更精準爭取預警應變作業時間。本研究以上龜山橋為實驗區，利用歷史事件之降雨量模擬河床水位高程及預測未來水位高程，並以歷史事件之水位站觀測資料進行成果檢核，確認是否達到預期的目標並評估可應用性以此做為納入防災預警機制之依據。成果顯示在強降雨情境下之應用，預測未來3小時水位成果在出現最強降雨量前2小時至後2小時誤差已落於-1公尺至1公尺間，恰適合應用於防災預警之用途。

關鍵字

公路水情防災預警機制； UAV測繪技術；多重尺度空間資訊；河川水位預測

並列摘要

The implementation of flood prevention and early warning mechanism in public bridges developed by Directorate General of Highways (DGH) has significant impacts on reducing disaster and protecting human life and property effectively. However, the current mechanism adopts historical disaster-affected rainfall as a basis to set up the rainfall threshold observation at each station, which could result in large uncertainties in some circumstances. In this study, UAV mapping technologies was proposed to acquire realistic 3D river terrain information. Then multi-scale spatial information and the hydrological model were successfully integrated for estimating the river water level in a more rigorous manner. By predicting accurately the water level at the cross section of the river where the bridge is located, it can offer additional time for the early warning and deal with emergency management. To validate the proposed approach, a real case study at ShangGuishan Bridge was performed and evaluated. The results illustrate that in the case of heavy rainfall situation, the predicted water level reached the uncertainty level within +/- 1 meter. It gives an evidence that the proposed approach can provide supporting information for the early warning mechanism in public bridges.