Sai Thong waterfall is a waterfall where water is originated from a water body in cavities of the karst limestone mountain by outflow down below along the hill slope into the La-ngu River. It is regarded as a tufa waterfall formed when water running over carbonate rock absorbs calcium. Aquatic plants which grow on the rocks in the stream and air in the atmosphere provide carbon dioxide during photosynthesis and water running which precipitates the calcium from the water to deposit it as layer of tufa on the surface of the waterfall – a process that takes millions of years. This tufa precipitation forms many curtain dams in form of many levels of terraces with spectacular water ponds and water curtains under shades of tree canopies.
