Officials from the Ministry of Environment check sea bass and spotted sea bass from the Nakdong River in Busan, caught after gates further downstream were opened from June to July 2021 as a second trial test of the impact on the area's ecology. Courtesy of K-water

Korea shares experiences reviving Busan's estuary region

By Ko Dong-hwan

Sea bass, Japanese eels and flathead mullets flutter on the deck of a fishing boat after being caught a few kilometers upstream from the Nakdong River estuary.

The catch was hauled in from the river in the southeastern part of Korea several months after all 15 gates around a river delta in the estuary blocking seawater from flowing inland were opened last February. The move came after three years of tests conducted by the Ministry of Environment to see how keeping the gates open would contribute to restoring the ecosystem around the estuary.

The presence of the fish proves the measure worked.

The estuary, where the country's longest river meets the sea, was marked by its ecologically ideal conditions for various water species. But the region's unique ecology started to deteriorate after the 2.4-kilometer-long Nakdong River Estuary Bank was introduced in 1987 to block the current and secure water resources for local farmers, factories and households in Busan, Ulsan and South Gyeongsang Province.

Studies conducted in the country so far have further highlighted the region's geographical and ecological traits, amid concerns that pollutants and microplastics can run into the sea and also where many river and sea creatures are born and spend their earliest phases. Purification of polluted river water before flowing into the sea has also been confirmed as the estuary's exclusive natural function.

K-water CEO Park Jae-hyeon speaks during International Estuary Symposium 2022 at BEXCO in Busan held from Wednesday to Friday. Courtesy of K-water

Because of the significant traits of the region, the ministry has been studying it for years trying to recover its natural habitat through more sophisticated ways of operating the gates. After test-opening the gates seven times and letting the seawater flow through the estuary from 2019 to 2021, the ministry confirmed its positive effects on improving the region's ecology.

The Nakdong River Water Commission Support Department ― directly under the country's presidential office ― officially launched new operational directives in February to leave the gates open and regularly examine water quality and wild species found in the region.

"We promoted to the world how we have revived the ecology of the estuary and introduced it as an exemplary case of a local estuary management," Park Jae-hyeon, CEO of state-run water resources managing and providing company K-water, said during the International Estuary Symposium 2022 held in Busan from Wednesday to Friday. "We will keep collecting data and performing scientific analysis to further improve the estuary's natural state."

Hosted by the Korean environment ministry and jointly organized by K-water and Korea Federation of Water Science and Engineering Societies, the symposium was held to share knowledge on best practices for managing the ecology of estuaries in different countries. Ryu Yeon-ki, an official at the Water Environment Policy Bureau under the ministry, said during the event that the authority will do its best to improve the estuary's environment so that humans and nature can coexist.

"We will keep sharing with the world our country's knowledge of ecological recovery of estuaries," the official said.

Officials from Korea's Ministry of Environment, K-water, Busan Metropolitan City and experts in river environment and engineering from Korea and other countries gather at the International Estuary Symposium 2022. Courtesy of K-water

One thing proposed at the symposium to participating experts from around the world was understanding the value of cleaning up pollution at estuaries through scientific methods. Marian Muste, an engineering professor at the University of Iowa specializing in hydroscience, delivered online a lecture on complexity in water flows at estuaries and how lower streams in the region should be monitored. Presenters who followed Muste explained in detail how they have examined water flows, water quality and ecosystems at the Nakdong River estuary following the gates' test-opening in 2019. They also shared the technologies used in monitoring, operating, assessing and predicting the environmental conditions of the estuary.

The symposium's last session on Friday is set to focus on how future governance of estuaries and local communities should evolve so that the two can mutually coexist.

"The symposium's main purpose is to improve the global competitiveness in looking after estuaries in different countries," Park said. "Having made notable progress in the ecological recovery of the Nakdong River estuary, we wanted to inform the global community about how we did it and which concerns should be taken into account to manage estuaries more comprehensively, including renewable energy sources available in the regions."

An official from the Aquatic Ecosystem Conservation Division under the Water Environment Policy Bureau said that the symposium purports to globally share Korea's "sustainable vision of comprehensive water management via scientific approaches" and propose a relevant model to experts from around the world.

Netherlands Ambassador to South Korea Joanne Doornewaard, Cardiff University civil engineering professor Roger Falconer, Macau University of Science and Technology President Joseph Lee and Tokyo City University engineering professor Kazumasa Ito have joined the symposium held at BEXCO as keynote speakers.