In 1991, South Korea embarked on an ambitious project to reclaim nearly 401 square kilometers of land and tidal flats from the Yellow Sea by building a system of two dikes extending 33 kilometers across the mouths of the Dongjin and Mangyeong rivers, offshore of the Saemangeum district (see Figures 1a and 1b). Called the Saemangeum Reclamation Project, the endeavor will allot about 283 square kilometers of the reclaimed land for crop production (mostly rice) through irrigation of the rivers' estuaries, which will be extended by about 23 kilometers when the bay fills up. The rest of the reclaimed land will be a water reservoir for agricultural use [Lie et al., 2008].
The construction of the Saemangeum Reclamation Project's northern dike was completed in June 2003; the southern dike was finished in April 2006. Two gaps in the southern dike allow water exchange, and two gates control the water level inside the dikes. The reclamation project, the biggest such endeavor in South Korea, is expected to be completed around 2030.