本研究以集水面積一蝕谷局部坡降關係、集水區凹曲率及蝕谷源頭集水面積一平均坡 降關係的分析爲主，邊坡作用和水文現象的田野調查爲輔，初步探討地表逕流侵蝕與其他 作用在清水溪兩岸主要礫岩集水區之蝕谷整體發育過程中所扮演的角色與相對重要性。結 果顯示，僅有無名四坑中少數一級蝕谷之集水面積-蝕谷局部坡降間呈現高度的指數負相 關性且集水區凹曲率低於-0.3，契合於由地表逕流侵蝕主導所造成的特徵，而主要集水區 與多數之一級蝕谷集水區則不符此條件。此外，主要集水區蝕谷源頭的集水面積與平均坡 降間也缺乏顯著的相關性。根據上述形貌特性研判，地表逕流侵蝕作用於研究區蝕谷網絡 的整體發育過程中或許存有某種程度的影響，但相對重要性在左、右兩岸均不高，未因其 地勢與地質構造關係的不同而具差異。近期以來，陡上邊坡的淺層崩落與滑崩相較於其他 地質動力調整作用而言乃發生頻率較高且對研究區蝕谷的向源侵蝕前進、側向拓寬甚或新 蝕谷的發育最具顯著效力，而研究區邊坡下緣地帶地下水位接近地面，水文環境利於滲流 侵蝕的發生，雖然今日的觀察中此項作用並非強烈，但無法排除滲流侵蝕在下游地區早期 的蝕谷發育階段中居於主導地位的可能性，相關問題有待日後尋求其他方法以進一步地深 入研究。

Relative significance between surface runoff erosion and other processes on the development of conglomeratic ravines near Chingshuei River is discussed in this paper. The related drainage area - gradient relationships are examined mainly in order to achieve the purpose. Field observation about slope and hydrologic processes is also conducted for obtaining the auxiliary explanation. Morphometric analyses reveal only few first-order basins located at Wumingsihkeng have a significantly high negative exponential correlation between contributing area and local slope of ravine, with a concavity exponent below -0. which is a typical characteristic caused by surface runoff erosion, but major watersheds and the most of first-order basins are not the cases. The correlation between basin area and average gradient above ravine head in major watersheds is also insignificant. They imply although the influence of surface runoff erosion exits, it maybe not the dominant process during the whole development of ravine network at both riverside areas those are different in the condition of topographic declination in respect to stratigraphic strike and dip. Shallow debris fall and avalanche at steep free faces seem to be the most frequent and effective dynamic resetting processes for head retreat, widening and reproduction of ravines at present. In contrast, seepage erosion is not intensive recently. Because the downstream zone of research watersheds is an advantage environment for seepage erosion due to the water table is very closer to land surface, and the intensity of seepage erosion could decreases with the propagation of ravine network, it has played a critical role at past stage of the development of ravine networks is possible. A further study will be necessary to resolve this question.