Dahua Caves Introduction
The valley terrain of the Keelung River features numerous smooth depressions known as "potholes" between Pingxi Station and Sandiaoling, in addition to waterfalls. These potholes are formed due to the uneven structural hardness of geological rock layers, which are eroded by river water carrying fine sand, creating cavities. Subsequently, small whirlpools formed within these cavities enhance the erosion process, ultimately resulting in bowl-shaped caves. Potholes typically appear in meandering river sections where swift currents and eddies occur, with exposed hard rock on the riverbed. The Dahuah Station area hosts the most concentrated and observable group of potholes, where a variety of pothole types can be found due to the interaction between water flow and rock layers, making it a natural geography classroom.
