The Hukou waterfall on the Huanghe River west of Jixian County, Shanxi, is formed when the river flows to the Hukou Mountains on the Shanxi-Shaanxi border and its 250-meter-wide bed, sandwiched between the canyons on its banks, abruptly narrows into a trough 50 meters wide and 30 meters deep and falls down into a big stone-strewn pool. The section of the river here is like the mouth of a water-flash. Hence the name of the waterfall, which means “ Flask Mouth waterfall”. The waterfall has a descent of 15-20 meters in the low-water season, but it is scarcely noticeable as a waterfall in the high –water season when the waters burst into rapid torrents. The section is rich in hydroelectric power potential