Refurbishment of four rivers’ tributaries

The four-river restoration project has lowered the risk of flooding, according to the results of an onsite survey of areas near the four rivers conducted by The Dong-A Ilbo and provincial experts. Dredge work that lowered water levels was found to have reduced the risk of floods. The Central Disaster Relief Center said heavy rains from June 22 to July 16 caused 160 billion won (152 million U.S. dollars) in property damage, or 10 percent of the losses Korea suffered in 1998 and 2006, when precipitation was similar to that of this year. No changes to river ecosystems were found. Water has not gotten murkier, either.

The restoration project is proceeding as scheduled and major work will be completed by year’s end. Among the eight reservoirs under construction along the Nakdong River, dredge and construction work of Sangju Reservoir, which is located in the uppermost region of the river, is 98 percent complete. Water is abundant in a river that once looked like a brooklet.

The restoration project has reaped results in the form of flood prevention and an increase in water levels. Tangible results will come when work on tributaries is completed, however. Environmental groups claim that the project will cause reverse erosion, or erosion of the river bottom and banks due to growing difference in water levels between the river’s main stream and tributaries. In reality, the speed and volume of water flow of certain tributaries of the four rivers increased due to heavy rain, causing their bottoms to erode and sedimentary layers to be exposed. In certain areas, earth and sand flooded into where dredge work was done.

A combined 2.2 trillion won (2.1 billion dollars) will be spent on the improvement of water quality in the four rivers. This money will go to waste if dirty water in tributaries flows into the main stream, however. Some worry that more than 500 billion won (475 million dollars), or 10 percent of the cost for the dredge work, should be spent every year on redredging. North Gyeongsang Province Gov. Kim Kwan-yong said at the construction site of the Sangju Reservoir on Saturday, “Without swift refurbishment of 70 tributaries of the Nakdong River, we cannot avoid negative side effects such as erosion, re-sedimentation and water pollution. Eco-friendly waterfronts will not be built, either.” The Han, Yeongsan and Geum rivers all have the same problem.

The refurbishment of a combined 5,500 kilometer-long tributaries in the four rivers is expected to cost up to 20 trillion won (19 billion dollars). Municipal and provincial governments are responsible for refurbishment of nearby rivers, but they cannot afford to due to financial difficulty. If the necessary funds cannot be raised at once, the central government should set a priority and conduct the work gradually. A presidential committee on regional development tried to submit to President Lee Myung-bak a report on a basic plan for tributary improvement, but failed to do so. For the success of the four-river restoration project, the government should devise a plan for tributary refurbishment and a fund-raising measure.