Manholes are a double-edged sword

Manholes protect the safety of the people, but they can become an object of fear in a disaster like the last heavy rains.

LEE KYOUNG-HEEThe author is the head of the Innovation Lab of the JoongAng Ilbo. A manhole is a hole through which people can enter and exit. It is a passage that vertically connects ground-level and underground facilities, such as waterworks and sewage, city gas, power lines and communication networks for repair and maintenance. Manhole covers prevent pedestrians and vehicles from falling in.

The history of manholes dates back to ancient Roman times. Roman civil engineers built an underground sewerage system with bricks to drain waste. As people had less contact with wastewater, the risk of infectious diseases was reduced and odor dissipated. Passages to access the sewerage for cleaning were created, and stone covers were placed atop the holes. Sewage infrastructure was completed around 100 A.D., which contributed to Rome’s growth to become a metropolis with a population of over 1 million. But with the fall of the Roman Empire, little further development had been made until the modern sewerage system was established in the mid-18th century.

As the urban population exponentially grew with the beginning of the industrial revolution in the 18th century, sewage and waste flowed into rivers and cities stunk. Edwin Chadwick, who worked for the Poor Law Commission in Britain, thought that the poisonous gas from the polluted water caused infectious diseases and advocated for the installation of a water supply and drainage system, flushable toilets, sewerage and sewer pipes. After the U.K. Public Health Act was legislated in 1848, modern waterworks and sewage systems began to be built.

According to “The History of Sewerage Development in Korea,” modern sewage facilities began to be built and repaired in the seven-year 1.62-million-won first-phase sewage repair project from 1918. Sewer pipes made of reinforced concrete were buried underground and circular manholes were installed in 35 locations: 13,115-meter-long open channels and 4,691-meter-long underground channels were built at the time. A century later, today, the total length of sewage pipes is 10,184 kilometers (6,328 miles) in Seoul and 163,099 kilometers nationwide. There are nearly 1 million manholes installed to access sewage pipes, and one-fourth are in Seoul.

Manholes protect the safety of the people, but they can become an object of fear in a disaster like the last heavy rains. Manhole accidents are rare but fatal. In the past 10 years, 15 people have died while working in the conduits and manholes. It should be a safe city for both pedestrians and underground workers.