Dahua Cave Introduction
The valley landscape of the Keelung River features numerous smooth depressions known as "potholes," alongside waterfalls. These potholes can be found between Pingxi Station and Sandiaoling, formed by the uneven structural hardness of geological rock layers being eroded by river water carrying fine sand. The flowing water creates small whirlpools in the depressions, which further erode the rock, resulting in the formation of these hole-shaped cavities. Potholes typically occur in the concave areas of river bends where turbulence and whirlpools are prevalent, and the riverbed is made up of exposed hard rock. The Dahuashan pothole cluster below Dahuashan Station is the most concentrated and observable area, showcasing nearly all types of potholes due to the interaction of water flow and rock layers, making it a natural geographical classroom.
