The four Major River Project was a project held in Korea from 2008 to 2013. Its purpose was to set aside water resources, increase water quality, restore river ecosystems, and create jobs. The work was to build two to eight dams in the Han River, Nakdong River, Geum River, and Yeongsan River and achieve the goals. However, the work didn?t go well and almost none of the goals were achieved.

Almost three years have passed since the project has ended, but we have many problems to solve. The biggest problem is the green algae that have covered the rivers that were related with the project. Because dams were made in the river, the water wasn?t able to flow, and the river ended up with a big amount of algae. They say that the best way to bring the rivers back to how they were is to let nature cure them. Because nature has the ability to recover itself, the rivers will also recover from the green algae. The first step to recovering is to open the gates of the dams and let water flow through the rivers.