Gezhou Dam, which lies within the municipal boundaries of the city of Yichang, Hubei Province, is situated roughly 2 kilometers from Nanjin Pass in the Xiling Gorge narrows. After passing through Nanjin Pass, the Yangtze broadens – from the pass' mere 300 meters to a whopping 2200 meters – into a deep, relatively calm, yet fast-flowing body of water that is ideal for hydroelectric power generation, which explains the rationale for placing a hydroelectric dam in this location. On the spot where Gezhou Dam now sits was once a small island, or islet, that split the flow of the Yangtze into three channels.
Gezhou Dam is 2561 meters across, 70 meters high, and has a depth, or wall thickness, of 30 meters. When completed in 1980, Gezhou Dam was China's largest, controlling a water volume corresponding to roughly half of the Yangtze's total capacity. Gezhou Dam was an enormous construction project, as its dimensions indicate, that attracted worldwide attention and boosted the tourist industry of the area, and even though the Three Gorges Dam itself is a much more stellar project, it too belongs to the same overarching power-generating and flood-control plan for this part of the Yangtze River as Gezhou Dam itself. Indeed, Xiling Gorge, the area of Hubei Province where Gezhou Dam is located, is one of the three gorges of the Three Gorges Dam area (the other two being Qutang Gorge and Wu Gorge, both located in Sichuan Province).
Gezhou Dam's status as China's largest hydroelectric dam has of course been definitively toppled with the completion of the Three Gorges Dam in 2007, as the latter is now not only China's largest, but the world's largest hydroelectric dam. Still, as part of this fascinating stretch of the mighty Yangtze River, Yichang's Gezhou Dam and nearby Xiling Gorge will forever remain noteworthy tourist sites. As far as the government of China is concerned, Gezhou Dam is perhaps better viewed as part of the same ambitious hydroelectric power-generating and Sichuan-basin flood-control plan that has finally culminated in the Three Gorges Dam, rather than as a competitor to the latter.
The major components of Gezhou Dam are its power stations and its shiplocks and sluices for permitting the passage of ships up and down the Yangtze. There are shiplocks for the usual variety of tonnage categories, i.e., from those for lighter craft to those designed for the passage of heavy ships carrying massive loads. Gezhou Dam generates 15.7 billion KWH of electricity annually, divided over two power stations and 21 generators. One of the power stations straddles the river's main flow, or stream, while the other straddles the river's secondary stream.
The dam project, which, in its time, took 10 years to complete (1970-1980), involved the removal of over 113 million cubic meters of earth and stone, which, to put it into more graphic terms, is enough earth and stone to construct a large mountain. One of the auxiliary benefits of Gezhou Dam – of which its planners were well aware, and which added to the rationale for constructing the dam in this location – is that it would raise the water level through Xiling Gorge, making the gorge, and especially Nanjing Pass, a significantly less treacherous waterway to navigate.
Gezhou Dam controls a watershed spanning some 100 square kilometers. When the dam was completed, it was immediately put to one of nature's severest tests when the 1981 flood sent raging water down a swollen Yangtze River at the rate of 72,000 cubic meters per second, significantly over the normal for the region, though the average flow rate of the Yangtze, seen in its entirety, is 90,000 cubic meters per second. Gezhou Dam, which is constructed to handle a maximum capacity of 110,000 cubic meters of water per second, could easily manage the flow rate of the Yangtze during the 1981 flood.*
As a grandiose project that attracted worldwide attention in its time, Gezhou Dam, with its magnificent floodgate, remains a compelling image to behold as the massive flows of the Yangtze spill over the dam's turbines, creating roiling torrents that roar with the sound of thunder. The violent force of these frothy water masses as they spill over the dam is contrasted by the utter tranquility and serene beauty of the landscape behind the dam, where some species may have suffered decline but where others have most certainly seized new opportunities.