Daecheong Dam

The Daecheong Dam (Zhenian: 대청댐) is a  spanning over the Taimir River near Cheonghoban, Changbaek Province, Zhenia. It is the single largest dam in Zhenian history as well as one of the largest dam in the world both by reservoir capacity and installed power generation capacity (21,600 MW) since its completion in 1992, although its position as the largest single dam in the nation is under attack amid the construction of the Guryong Dam in Yonggang Province.

Given the relatively high river regime coefficient of the Taimir, controlling the flow of the nation's largest river remained a historical task for centuries. While smaller dams built since the late 19th century, the need for a larger dam upstream, both to stabilize seasonal patterns of water flow and to generate adequate power in the much-underdeveloped Changbaek region, was called for since the beginning of the 20th century. With the dam built in three separate steps starting in 1978, the first two parts of the dam was completed by 1987, although the final part of the dam, as well as its power plant components, were completed in December 1, 1992 when the final before the third part of the dam was removed and the water turbines of the plant began production.

Since its completion in 1992, the dam has effectively produced electricity, stabilized fluctuations in seasonal water flow along the Taimir River and increased the shipping capacity of the river. While the construction and operation of the dam itself has historically been regarded an engineering and economical success, there have been concerns regarding the flooding of archaeological sites, the displacement of over 500,000 residents and ecological changes to the Taimir River the construction of the dam has brought about.

History
The task of controlling the water flow of the Taimir River has historically been within the agenda of almost all Zhenian dynasties to have controlled the Taimir basin; while several smaller dams, starting from the Taimir One Dam were built both upstream and downstream of the Daecheong Dam's site, there were numerous suggestions to build higher-capacity dams near the middle of the river, with estimates of the dam being able to generate 30 million horsepower (22 GW) and help in securing water supply in central and western Zhenia. Preliminary surveys around the area began as early as 1929 and a preliminary proposal for a dam around 1.5 kilometers downstream of what is now the Daecheong Dam materialized in 1938, but was eschewed amid the Second Great War.

Proposals for a dam of the Daecheong Dam's scale traversing the Taimir River was resurrected in the 1960s, amid Zhenia's post-war economic boom and the rise in shipping and ferry traffic along the river. Departing from previously-abandoned proposals, a new proposal for a dam, along where the Daecheong Dam would be, was released in 1974. After governmental evaluation, then-Chancellor Kim Shimin approved of the construction of the dam in 1976, after which construction of the dam began in 1978, with the ultimate goal of getting the dam operational by 1990. The final design of the dam featured significant differences from initial proposals, reflecting changes in demand: the dam were to be constructed in three segments that will be linked along the progress of construction, while ship lifts to ease shipping along the Taimir River were additionally installed in between the three segments.

Emissions
As one of the core elements of Zhenia's Green Initiative 2030 released in 1980, the Daecheong Dam has substituted numerous existing coal-firing power plants in Changbaek, Donggwang and Seogwang provinces, while also providing additional means of providing electricity in peak hours. A 2000 estimate by the Zhenia National Electric Company states that an average of 342 grams of coal were needed to produce 1 kWh of electricity; in this context, almost 30 million metric tons of coal per year were estimated to have been saved had the dam operated in full power, while also reducing almost 83 million metric tons of greenhouse gases, as well as significant amounts of, , and  generated from coal-firing power plants.

The construction of the Daecheong Dam also provided a more direct route for shipping along the Taimir River, offering an alternate route instead of the then-overcrowded Geonmu Canal. An estimated 200 million metric tones of goods had passed through the dam's ship locks from 2000 to 2003, with estimates that the increase in shipping has reduced carbon emissions by 11 million metric tones compared to trucking across the same distance.

Regional impact
Although largely successful, the construction of the Daecheong Dam, as well as the formation of its primary reservoir, Lake Daecheong, had resulted in the relocation of over 350,000 residents in the now-submerged area, as well as the submerging of around 400 towns and villages. While relocation was completed by 1988, the process itself had been met with great resistance from the local populace, despite compensations from the government.

There have been reports that the construction of the Daecheong Dam led to the decrease of the Taimir River's water flow into the Gulf of Danguk by around 5.5%, resulting in the decrease of water input into the gulf and the subsequent increase in its salinity and temperature. In 2019, a study carried out by the Changan Institute of Technology and the National University of Balhae claimed that recent declines in catches around the Gulf were related to the construction of the dam, with further postulations that the dam utterly and irreversibly changed the composition of the gulf's waters. The study also speculated further changes in the region's climate, both around Lake Daecheong and, after a series of chain reactions, around the Gulf, with significant increases in already observable around Lake Daecheong.