Huanghe Hukou Waterfall National Geopark (Shanxi, Shaanxi)
This national geopark is trans-provincial in nature and extends across Shanxi and Shaanxi provinces with an area of 29 km2. It became a national geopark in 2002. The Hukou Waterfall is the largest waterfall on the Yellow River. It is 20 to 30 m wide, more than 20 m long and has a flow rate of 1000 m3/s. The falling water generates massive waves tens of metres long that create the roaring sound of ‘the thunder of valley’. Shili Long Groove’ is the narrowest part of the Yellow River. It is 4,200 m long and 30 to 50 m wide. It is the result of the erosion of the waterfall towards the source. The undercutting effects of the river are very strong. Numerous potholes caused by water erosion have formed in the bedrock. The bedrock that forms the Hukou Waterfall is mainly interbedded sandy shale, soft mudstone and shale, and hard thick sandstone of the Triassic (approximately 200 million years ago) Zhifang Formation. The waterfall is magnificent because of its powerful flowing water.