Three Gorges primarily famous for its scenery, the Three Gorges region is also historically and culturally important in China. Many settlements and archaeological sites are in danger of being submerged by the rising reservoir of the Three Gorges Dam. Due to the lithological conditions of its different regions, the valleys of the Three Gorges are narrow in some areas and broad in others. Most narrow valleys occur in regions where there is limestone, which is relatively hard and resists erosion. However, water can flow along deep vertical fractures, eroding underneath. As the limestone bed is gradually undercut, parts of it fall into
Panjiakou Dam seen on a small island off the reservoir's edge at , particularly during droughts when the reservoir holds less water. The scenery around the reservoir is a popular tourist destination and with the surrounding terrain, it is often called "Qianxi Little Three Gorges". The Panjiakou Dam is a tall and concrete gravity dam. The dam's reservoir has a capacity of and surface area of . Of the reservoir's capacity, is active (or "useful") for power generation and water supply. The dam sits at the head of a catchment area which constitutes 75 percent of the Luan River basin. The dam's