Jinping-I Dam

Jinping-I Dam, double curvature arch dam and hydroelectric project situated at the Jinping Bend of the Yalong River, a tributary of the Jinsha River and eventually the Yangtze River, in Sichuan province in China. One of 21 hydroelectric power stations on the Yalong, it is currently listed as the tallest human-made dam in the world, reaching 305 meters (1,000 feet) at its maximum height, 5 meters (16 feet) higher than the Eiffel Tower in Paris. At its crest, its length is 569 meters (1,867 feet). Construction on the project began in 2005, with the first power station becoming operational in 2013.

Background and location

Jinping-I’s construction was part of the Chinese power infrastructure initiative known as the West-East Electricity Transfer Project. Initiated during the 10th Five-Year Plan (2001–05), the project aimed to uplift China’s historically underdeveloped western provinces while also supplying the much more populous eastern regions with electricity. The Jinping-I dam in the southwestern Sichuan province was one of the most ambitious undertakings of this transfer project.

The Jinping Bend had long been a primary candidate for hydroelectric projects before Jinping-I began construction. It is one of the steeper sustained drops for the Yalong, a river already noted for its high elevation and torrential rapids. The bend is nestled in between the Muli Tibetan Autonomous county and the Yanyuan county, both part of the Sichuan province. The geographic area is noted for its high elevation because of its proximity to the Jinping mountain range, whose highest point Jinping Shan is about 4,000 meters (about 13,000 feet) above sea level. The Jinping Bend, 150 kilometers (93 miles) in length, guides the Yalong River down a V-shaped narrow valley that drops 310 meters (about 1,020 feet) over a remarkably short distance of 16 kilometers (10 miles), providing ideal conditions for harnessing the river’s power.

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Design and construction

The Jinping-I Dam was designed by the Chengdu Engineering Corporation Limited, which also conducted feasibility studies prior to construction. Sinohydro Bureau 7 Co., Ltd., undertook the construction, and the project is currently owned and operated by Ertan Hydropower Development Company, Ltd. Construction began on November 12, 2005, and the river was closed slightly more than a year later. Water impounding (accumulation of water in the reservoir) began on November 30, 2012, and power generation commenced on August 30, 2013.

Jinping-I’s power station has six separate units, each capable of producing 600 megawatts of energy. The project is capable of producing more than 16 billion kilowatt-hours of power every year and has power regulation capabilities, allowing seasonal variations in power generation to cater to demand. Francis turbines in each unit harness this immense energy, fed by a reservoir 1,880 meters (6,168 feet) in height and 82.55 square kilometers (31.87 square miles) in area. The reservoir is capable of storing 7.76 billion cubic meters (about 274 billion cubic feet) of water, of which roughly 5 billion cubic meters (about 175 billion cubic feet) are currently in use.

Flood control is provided by four spillways at the dam’s surface, five outlets at its base, and a tunnel that expels water downstream to Jinping-II, another hydroelectric project built during the same period. Jinping-II notably houses the world’s largest hydraulic tunnel complex. The Jinping-I dam is credited with catalyzing major technological developments in hydroelectric infrastructure; its structural integrity at its great height and mass as well as its incredible discharge volume are touted as the project’s primary successes. Jinping-I’s construction also notably avoided deforming surrounding rock structures; a massive achievement given the potential issues that can arise from building in such a geologically complex area.

Environmental impact

About 7,000 people are believed to have been relocated to build the Jinping-I Dam. Additionally, the dam’s impoundment process and reservoir filling have been blamed for more than 300 earthquakes in the Sichuan province. This phenomenon, called reservoir-induced seismicity (RIS), is believed to be a direct consequence of water being channeled into the reservoir. Some studies indicate that much larger seismic events could transpire in the future. Many have pointed to the Zipingpu Dam in Wenchuan, Sichuan, as the culprit for a 2008 magnitude-8 earthquake that killed about 90,000 people, amidst worries that Jinping-I could cause a similar catastrophe. However, despite regular seismic activity in the region, no large earthquakes have been detected since the Jinping-I Dam’s impoundment.

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