The Gezhouba Dam or Gezhouba Water Control Project on the Yangtze River is located in the western suburbs of Yichang, in central China's Hubei province. One of the largest run-of-the-river dams, it sits several kilometers upstream from downtown Yichang, just downstream of the fall of the Huangbo River into the Yangtze. Construction started on December 30, 1970 and ended on December 11, 1988. The dam has a total installed electrical capacity of 2,715 MW. After rushing out of Nanjin Pass (南津关, "South Ford Pass"), the Yangtze River slows down and widens from 300 m to about 2200 m at the dam site. Two small islands, Gezhouba and Xiba, divided the river into three channels. There the Gezhouba Project was built. The facility boasts a generating capacity of 2.71 GW along with three ship locks, two power stations that generate 14,100 GWh of electricity annually. It has 27 gates of spillway, and a non-flowing Dam on both banks. The dam is 2595 m long with a maximum height of 47 m. The reservoir has a total volume of 1.58 km3. The navigation lock No.2 on the third channel was, when built, among the 100 largest in the world. The lock chamber is 280 m long and 34 m wide, with a minimum draft of 5 m at the sill. It provides passage for 10,000 ton ships. The construction of the Gezhouba Dam, and others on the Yangtze, is considered by scientists to be one of the main causes of the decline and extinction of the Chinese paddlefish.