應用透水鋪面於改善水量水質之研究

Abstract

近年來，全球氣候變遷速度加快，全球平均氣溫逐漸升高導致極端自然災害事件發生頻率上升，對生物物種之生存環境產生嚴重影響。另外，隨著工業化進程發展，全世界範圍之城市人口比例已超過總人口的一半，在城市開發的過程中土地不透水面積增多，同時豐水期和枯水期差異更加顯著，強降雨時地表徑流量增加以致於地下水無法有效補充，改變原有的自然生態環境。為彌補過度開發對環境造成之負面影響，以低衝擊開發概念應用於城市基礎設施，加強極 端自然災害下城市之韌性，因此綜合評估低衝擊開發管理技術於不同降雨情境之效率成為其中重要一環。 城市淹水主要因地表不透水面積比例較大，雨水多從地表進入排水系統，為減緩淹水對城市環境之影響，本研究首先針對低衝擊開發之透水鋪面設施進行物理試驗，於實驗室搭建壓克力水箱 (60cm*120cm* 60cm)，設置均勻降雨系統還原實際降雨，以固定濃度之食鹽水作為地表污染物之替代物，分析透水鋪面對降雨洪峰流量、洪峰到達時間和地表徑流水之鹽度之影響。另外，不同降雨情境下透水鋪面對地表徑流水量與水質之處理效率有所不同，本研究透過 使用荷蘭Delft3D軟體，對物理模型試驗之結果進行驗證，並設置不同降雨重現期、不同降雨偏態係數和不同降雨歷時之參數分析透水鋪面於各情境下之指標變化情況，包括降雨洪峰削減率、洪峰延後時間和鹽度去除率。 結果顯示，以臺北氣象站1951年至2011年5月最大降雨量為數據樣本，透水鋪面於短降雨重現期、偏態係數 (r=0.4至0.6)、短降雨歷時之情境下對洪峰之減緩作用較顯著，其極限承載範圍為重現期 20 年至30年之雨量，於50年降雨重現期對洪峰無減緩作用，但鹽度去除率保持緩慢上升並維持於72.6%至85.31%，希望本研究結果對後續透水鋪面規劃設計提供參考價值並在緩解城市洪水災害起到一定幫助。

In recent years, global climate change has accelerated and the global average temperature has gradually increased, leading to an increase in the frequency of extreme natural disasters, which have a serious impact on the living environment of biological species. In addition, with the development of industrialization, the proportion of urban population worldwide has exceeded half of the total population. In the process of urban development, the impervious area of land has increased, and the difference between the periods of abundant water and dry water has become more significant, resulting in the increase of surface runoff during heavy rainfall and the ineffective replenishment of groundwater, which changes the original natural ecological environment. In order to compensate for the negative impact of overdevelopment on the environment, the concept of low-impact development is applied to urban infrastructure to enhance the resilience of cities under extreme natural hazards, and therefore it is important to evaluate the efficiency of low-impact development management techniques for different rainfall scenarios. In order to mitigate the impact of flooding on urban environment, this study first conducted physical tests on permeable pavement facilities for low-impact development by setting up acrylic water tanks (60cm*120cm*60cm) in the laboratory, setting up a uniform rainfall system to restore the actual rainfall, and using a fixed concentration of salt water as a proxy for surface pollutants. The effect of permeable pavement on the flood flow, flood arrival time, and salinity of surface runoff was analyzed. In addition, the efficiency of permeable pavers on surface runoff volume and water quality varies under different rainfall scenarios. and salinity removal rate. The results showed that, using the maximum rainfall from 1951 to May 2011 at Taipei Meteorological Station as the data sample, the permeable pavement had a significant effect on flood peak mitigation under the scenarios of short rainfall recurrence period, skewness coefficient (r=0.4 to 0.6), and short rainfall history, and its limit load range was from 20 to 30 years of recurrence period. It is hoped that the results of this study will provide a reference value for the subsequent planning and design of permeable pavement and help to mitigate urban flooding hazards.