山坡地都市化對下游洪峰流量影響之研究

The Impact on Peak Discharge from the Slopeland Urbanization

何智武(Neal C. Ho) ； 林致遠(Chih-Yuan Lin)

《中華水土保持學報》 26卷3期 (1995/09) Pp. 221-234

https://doi.org/10.29417/JCSWC.199509_26(3).0007

摘要

本研究係針對臺北都會區四周之山坡地，進行連續之地文與水理分析，目的在了解山坡地都市化對洪災之影響，期就定量之研究之分析，推估不同型態之土地利用及開發度，對下游水文環境所造成之衝擊，並提出對應之建議。本研究首先建立臺北市山坡地開發程度與其地文條件之評估模式，再配合於山溝谷口間設置水文環境監測站，以掌握山坡地之動態水文資料。經評估結果，本研究共規劃設置六座水文環境監測站，對都市化山坡地之尖峰流量、稽延時間、泥沙產量、地下水位及水質變化進行長期監測。其監測資料，經驗證分析之結果顯示，當集水區不透水面積提高至40％時，其洪峰流量將提高2.7倍；同時亦發現當集水區不透水面積在5％以下時，其洪峰流量增加並不顯著，但不透水面積提高至20〜40％範圍之間時，其洪峰流量則有顯著提升之現象。故於高度都市化集水區進行水理分析時，應特別考慮都市化現象對逕流機制之影響，同時該集水區之總開發度亦不宜超過30％，以避免對下游之水文環境造成衝擊。

關鍵字

都市化 ； 洪峰流量 ； 水文環境

並列摘要

The objective of this research is to study the impact on rainfall-runoff characteristics of slopeland urbanization in Taipei by the investigation of the hydro-environmental change for slopeland development and different types of landuse sites. The hydrologic charactedristics studied include the evaluation of the relationships between percentage of development and allowable landuse capability. And, the results achieved are then applied to the planning of field monitoring system for the hydro-environmental study in the future. As the results, six observation stations were established in Taipei. The observation items include the rainfall intensity, sedimentation, water quality and hygrograph on the time scale. The preliminary analysis of field records compared with unit hydrograph shows that, the impervious area of watershed has been increased 40%, the peak discharge will increase 269%. And for low percentage of impervious area (0~5%), the increase of it will cause the peak discharge to increase mildly. But for high percentage of impervious area (20~40%), the increase of it will cause the peak discharge to increase dramatically. As a whole, the critical point of the degree of impervious area for the slopeland is around 30%. Above it, the impact of urbanization will accelerate.

並列關鍵字

Urbanization ； Peak Discharge ； Hydro-Environment