The South Korean government has injected almost 22 trillion won ($19.6 billion) into a massive rivers development project since its launch in 2008, data showed Wednesday.

According to government data, 11.85 trillion won, about half of the cost poured into the project, was spent on works on the Nakdong River, the longest river in Korea.

About 3.67 trillion won was used on the Han River, while 3.4 trillion won was spent on the Geum River and 3.36 trillion won on the Youngsan River.

The money was spent on the rebuilding of 87 old dams, the construction of 16 new ones as well as the reinforcement of some 300 kilometers of riverbanks on the nation’s four main rivers, the government said.

Although the project was initiated to prevent water shortages, improve water quality and create riverside tourism spots, critics have called it a failure with disastrous damage to the environment.

The presidential office Cheong Wa Dae on Monday ordered a policy inspection of the four rivers development project. It will be the fourth round of inspections conducted by the government, after two under the Lee Myung-bak administration and one under his conservative successor Park Geun-hye.