A major waterfall landscape maintained by fog drip water

Abstract. The Chishui forest region in the southwest of China has a unique landscape with thousands of waterfalls that produce a significant water yield even during and after a long dry period. However, the sources of water for sustaining the waterfall landscape are poorly understood. We use stable isotopes ²H and ¹⁸O to trace water in surface runoff and determine the runoff generation mechanism in the catchments. Located on the pathway of water vapor from the neighboring Sichuan Basin, the area is covered by a thick forest canopy above sandstone strata. The local conditions combine to create a microclimate that favors formation of fogs at relatively high frequencies. It was found that frequent fogs in this region act as a key water supplier for waterfalls and play an important role in the regional hydrology. During the dry period starting from October, waterfalls are mainly sustained by baseflow, 8–31 % of which comes from frequent fog water recharge. The waterfall landscape in the Chishui forest represents a unique characteristic of the regional hydrological system in close connection with its geographical location, geology, climatology and ecology.