[Report] 'Hinnamno Damage' POSCO Builds Iron Fortress with 2m Water Walls and Powerful Pumps

Pohang Steelworks Prepares for Summer Heavy Rain and Typhoons
After Last Year's Hinnamnor Damage, Resolute Recovery
2m Water Walls Installed Over 1.9km and 30t Floodgates
Double and Triple Protective Barriers at the 'Heart of the Steelworks' Substation

On the afternoon of the 19th, at Pohang Steelworks in Nam-gu, Pohang City, Gyeongbuk, a 1.9 km section from the steelworks main gate to gates 2 and 3 is surrounded by a 2-meter-high flood barrier. After suffering significant damage from Typhoon Hinnamnor last September, POSCO has established multiple layers of 'determined' countermeasures to completely block any recurrence of a second Hinnamnor. A representative example is the flood barrier, reminiscent of a 'small fortress.' The flood barrier consists of 3-meter-high precast concrete (PC) retaining walls, fixed up to 1 meter underground. The PC retaining walls are made by pre-manufacturing reinforced concrete components at a factory and curing them, resulting in higher strength than concrete cast on-site. Slag (a steelmaking byproduct) from the blast furnace was also incorporated to create an eco-friendly retaining wall.

Gong Ryun-ho, Manager of POSCO's Purchasing and Investment Headquarters, said, "During last year's typhoon damage, the inside of the steelworks was submerged under about 1.5 to 1.7 meters of water." He emphasized, "Assuming a typhoon or heavy rain situation with over 100 mm of rainfall per hour, similar to Typhoon Hinnamnor, we ran simulations and concluded that a 2-meter-high flood barrier could prevent flooding damage inside the plant." POSCO reviewed flood prevention measures immediately after the flooding in September last year, began construction in December of the same year, and completed the flood barrier construction last month. The project involved as many as 12,000 personnel.

POSCO, the largest steelmaker in Korea, suffered unprecedented damage last year when its blast furnace stopped operating. For the first time in its 54-year history since its founding, POSCO halted plant operations. Water and soil filled underground areas several meters deep, and water rose up to 1.5 meters above ground, turning the area into a 'mudflat.' The estimated damage to the steel industry from last year's typhoons and heavy rains reached 2 trillion won. The aftermath continued into early this year. Among steelmakers, POSCO suffered the greatest damage. The main cause was the flooding of Naengcheon Stream near Pohang Steelworks. During the typhoon damage, floating debris accumulated on the Naengcheon Bridge in front of Gate 3 of Pohang Steelworks, blocking the water flow, and the swollen river water surged into the steelworks.

POSCO installed iron gates weighing up to 30 tons and measuring up to 29 meters long at the three main gates used by vehicles and employees. When heavy rain is expected, these gates close to completely block water from entering from outside. The iron gates operate with four motors; the gates lift about 5 cm off the ground, slide closed, and then lock in place.

Im Gi-dae, team leader of the Civil Engineering Equipment Technology Department at Pohang Steelworks, is explaining the sheet piles installed near Naengcheon in Nam-gu, Pohang, Gyeongbuk, to prevent flood damage. The sheet piles are driven 15 meters deep below the concrete and are installed along approximately 1.6 km of the embankment. Photo by Jeong Dong-hoon

The power substations supplying electricity to the steelworks, known as the 'heart of the steelworks,' were 'exceptionally' protected. Double flood prevention facilities were installed at seven substations within the steelworks. Flood prevention facilities were installed at each building's entrance, and 1.5-meter-high concrete walls were erected outside the buildings. Additionally, fixed water pumps capable of pumping 12 tons of water per minute were installed to prepare for emergencies. Lim Gi-dae, Team Leader of the Civil Engineering Equipment Technology Department at Pohang Steelworks, said, "During last year's flooding, water entered the substations, causing a complete halt in plant operations," and added, "We are thoroughly prepared with the mindset that the substations, essential for plant operation, must be protected at all costs."

At the breached Naengcheon embankment, 4,000 steel rods were densely driven in. This is to prevent water from overflowing into the steelworks even if the earthen embankment is washed away by flooding. Team Leader Lim said, "We installed wide steel sheets called 'sheet piles' underground to a depth of about 15 meters along a 1.6 km section toward the steelworks. This was done in consultation with Gyeongsangbuk-do Province and Pohang City."