Restoration of Nakdonggang Estuarine Brackish Ecosystem Underway... Minimizing Salt Damage

Decision of Nakdonggang Basin Water Management Committee
Creation of Estuarine Area within 15km Upstream of Hagutduk

[Asia Economy Sejong=Reporter Dongwoo Lee] Starting from mid-this month, seawater inflow will begin upstream of the Hagutdok to actively restore the brackish water (a mix of freshwater and seawater) ecosystem in the Nakdong River estuary.

According to the Ministry of Environment on the 10th, the Nakdong River Basin Water Management Committee resolved the 'Nakdong River Estuary Brackish Water Ecosystem Restoration Plan' through a written review.

This is a recovery measure following the simplification of fish species and the decline of migratory birds caused by biodiversity damage after the construction of the Hagutdok in 1987 for agricultural, industrial, and domestic water supply and flood control. The ecosystem restoration technology secured through the 'Nakdong River Hagutdok sluice gate pilot opening' implemented since 2017 greatly helped in carrying out this project.

The Ministry of Environment stated that through the pilot opening, technology was secured to simultaneously proceed with stable water supply without salinity damage and brackish water ecosystem restoration. After seawater inflow, more brackish water fish species such as eels and sea bass were observed upstream of the Hagutdok than before.

This Nakdong River Estuary Brackish Water Ecosystem Restoration Plan will first extend the seawater inflow period from the existing 4 months to every month during each tidal cycle. During this process, a brackish water zone will be created within 15 km upstream of the Hagutdok to observe water quality and ecological changes, ensuring no problems in agricultural, industrial, and domestic water supply in the lower Nakdong River area. The tidal cycle refers to around the lunar full moon and new moon, when the tide level is high and seawater inflow is possible upon opening the Hagutdok sluice gates.

When salinity reaches 10 to 12 km upstream of the Hagutdok, seawater inflow will be stopped to prevent salinity damage in the Seonakdong River basin, which is used for agricultural water. To restore the naturalness of the Nakdong River estuary brackish water ecosystem, ecological restoration will be promoted considering the ecosystem before the construction of the Hagutdok as well as climate and environmental changes.

Environmental improvements in the Seonakdong River basin will also be pursued. Observations of changes in salinity in rivers, soil, and groundwater will be strengthened, and the results will be disclosed to reflect future policy directions in cooperation with related agencies, experts, and local residents.

In the mid to long term, to completely block salinity inflow into the Seonakdong River basin and ensure stable water supply, improvements to the Daejeo sluice gate and canal facilities will be carried out simultaneously. Before these facility improvements, an emergency discharge system will be established through coordinated operation of upstream dams, weirs, and the Hagutdok to prevent salinity damage.

In case salinity damage occurs despite the above preventive measures, emergency agricultural water supply using pumps and water trucks will be provided with support from related agencies, and damage relief will be considered through environmental dispute mediation systems.

Additionally, a 'Nakdong River Estuary Forum (tentative name)' will be formed and operated to broadly discuss various topics such as ▲ directions for brackish water ecosystem restoration, ▲ activation plans for estuary ecotourism, and ▲ support measures for coexistence and income increase of farmers and fishermen. Cooperation among related agencies will be strengthened to enhance integrated management of rivers, estuaries, and coastal areas, while legal and institutional foundations will be organized.

Lee Jin-ae, Chairperson of the Nakdong River Basin Water Management Committee, said, “I hope that the resolution of this Nakdong River Estuary Brackish Water Ecosystem Restoration Plan will be an opportunity to restore the precious natural value of the Nakdong River estuary,” and added, “We ask for active cooperation from related agencies to ensure there is no problem in securing agricultural, industrial, and domestic water.”

This content was produced with the assistance of AI translation services.