八掌溪集水區降雨量與逕流量之研究

The study of the relation between rainfall and runoff in Pa-Chang River watershed

陳昭宇(Chaw-Wu Chen)

指導教授 ： 林意楨

淡江大學/工學院/水資源及環境工程學系碩士班/碩士(2007年)

https://doi.org/10.6846/TKU.2007.00606

摘要

本研究探討分析集水區在降雨過程中，降雨量與逕流量之相互關係，彙整1995年至2004年八掌溪流域之觸口集水區、軍輝橋集水區、常盤橋集水區十年間，每年最大日逕流量與日降雨量資料，並說明集水區集流時間、逕流係數推求之方法，以利分析八掌溪流域之相關研究。利用地理資訊系統分析歸納出各集水區土地開發情形及坡度分級，討論各集水區不同之坡度與集流時間、降雨強度之關係，將各集水區土地開發使用程度與逕流係數作討論分析。本研究所推求之過程，是由實測資料所得能反應歷史洪水資料之統計特性，提出初期評估八掌溪流域水文特性之影響。研究結果顯示，在直線迴歸分析與對數迴歸分析中，除觸口集水區外，其餘集水區之相關性較佳，所以未來再進行類似之研究分析時，為求有較合理之數據或結果，需依照不同的集水區特性選擇適合之迴歸分析方法。在坡度分析中，發現颱風暴雨事件時集水區之坡度對集流時間及逕流量會造成影響；在土地開發程度分析中，發現各集水區土地開發程度越高，降雨的滲透能量減少，草木截流與地表阻流功能消失，導致逕流係數C增大。

關鍵字

逕流係數 ； 合理化公式 ； 集水區 ； 降雨強度 ； 逕流量 ； 地理資訊系統

並列摘要

This research had collected the maximum daily runoff and daily rainfall data of Chu-Cow watershed, Chang-Pan watershed, and Gin-Haw watershed, which are located in Pa-Chang River basin, from 1995 to 2004. It also explained the ways of reasoning the time of concentration and runoff coefficient in different watersheds. This research makes use of Geographic Information Systems to analyze the effects of the degree of development and slope of each watershed. The relationships between different watershed’s slope, time of concentration and rainfall intensities were also discussed. This preliminary research inquired into the statistical characteristics from the actual measurements in the historical flood, and summed up the influences of the geographically characteristics of Pa-Chang River watershed. The results of this research showed, except for that Chu-Cow watershed, that the correlation between surface runoff and river discharge are moderate. In analyses of the effects on slope, we have found that during typhoon and torrential rain, the slope of watershed did affect the time of concentration and runoff coefficient, because of the higher urbanization of Pa-Chang River, including the increase of population, and changes of land exploitation. Among the urbanized district, the various floods of medium and small rivers gather rapidly, and they often cause serious flooding in the downstream area. This research suggests that the use of Geographic Information Systems to investigate the watershed environment is essential in the future. Owing to the relationship between nature environment and land exploitation are complicated, it could have great differences according to the various characteristics for different districts.

並列關鍵字

Runoff coefficient ； Rational formula ； Watershed ； Rainfall intensity ； Runoff ； Geographic Information Systems

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