In a land reclamation project in 1993, a massive seawall was constructed in Gyeonggi Bay which created Lake Sihwa. The goal of this 12-kilometer long embankment was to reclaim lost metropolitan land, create water that could be used for irrigation, and flood mitigation. Following the completion of the seawall, Lake Siwha was cut off from freshwater inflows. Beginning the deterioration of the ecosystem of the lake. The development of three new city's industrial wastewater and domestic sewage flowed into the isolated lake rapidly contaminating the water. By 1997, the lake’s water was so polluted that it no longer could be used for irrigation or sustain marine life. To solve this issue, Korea started periodically opening gates to allow freshwater to enter but this was not enough. K-water, Korea’s governmental water authority commissioned the Sihwa Tidal Plant as a solution to the problem and in 2002, the project was approved. 

Sihwa Tidal Plant is one such plant that generates power via tidal barrages. Created in South Korea, this power plant was commissioned by K-water the government agency in Korea that's responsible for water resource development and industrial water supply. It went into construction in 2004 and was finished in 2011. Being the world’s largest tidal power plant it creates a ton of power; generating about 552.7 GWh per year. This power plant wasn’t just constructed to decrease Korea’s Petroleum imports, it was created to fix an environmental problem Seoul’s government created in 1993. Now, Sihwa Tidal Plant generates enough electricity to power approximately 500,000 houses and has decreased the COD (Chemical Oxygen Demand) levels from over 4 PPM down to 2 PPM. The lake is slowly approaching the COD levels of the Yellow Sea, which is it’s neighbor, suggesting that it is healing and stepping away from its nickname: “dead lake.” K-water pushing its environmental initiatives has developed a public recreational and a 75-meter tall observatory around the plant. There success is marked by the 1 million visitors to the Sihwa power plant since the opeing of the observatory in 2014.