Key Facts
In response to a road collapse incident in Yashio City, Saitama Prefecture, local authorities have announced a comprehensive plan to address aging infrastructure by implementing a dual sewage pipeline system. This decision was presented during a meeting of experts on April 23, 2025, and is expected to take approximately 5 to 7 years to complete.
The collapse, which occurred on January 28, 2025, was caused by the corrosion and subsequent failure of a large-diameter sewage pipe located about 10 meters underground. The damaged pipe, measuring approximately 4.75 meters in diameter, led to significant ground subsidence in the area. As an immediate measure, the damaged section will be repaired by installing a smaller, 3-meter-diameter pipe inside the existing structure, while undamaged sections will be reinforced. The full restoration of the damaged pipeline is targeted for completion by the end of fiscal year 2025.
To mitigate future risks, the Saitama Prefectural Government plans to construct a second sewage pipeline parallel to the existing one over a 2-kilometer stretch near the collapse site. This dual-pipeline system will allow one pipe to be taken offline for maintenance while the other remains operational, ensuring long-term durability and functionality. The project may extend to downstream sections, though the exact costs and timeline for this expansion remain undetermined.
Currently, temporary measures are in place to manage sewage flow. Hoses are being used to divert wastewater from upstream to downstream areas, and a temporary drainage pipe is under construction, with completion expected by mid-May 2025. Once these measures are finalized, authorities will intensify their search for the truck driver who went missing during the collapse.
The committee overseeing the project, led by Professor Hiroaki Morita of Nihon University’s Faculty of Industrial Engineering, has expressed support for the dual-pipeline approach. Morita stated that while technical evaluations are necessary, the proposed timeline of 5 to 7 years is reasonable and essential for effective maintenance.
For more details, visit the Tokyo Shimbun article.
In response to the road collapse in Yashio City, Saitama Prefecture, authorities have outlined a plan to enhance infrastructure resilience by introducing a dual sewage pipeline system. The collapse, which occurred on January 28, 2025, was attributed to the corrosion and failure of a 4.75-meter-diameter sewage pipe located 10 meters underground. This incident caused significant ground subsidence and left a truck driver missing.
As an immediate response, the damaged section will be repaired by installing a smaller, 3-meter-diameter pipe within the existing structure, while undamaged sections will be reinforced. Full restoration is targeted for completion by the end of fiscal year 2025. Temporary measures, including wastewater diversion through hoses and a temporary drainage pipe, are underway, with completion expected by mid-May 2025.
To prevent future incidents, a second pipeline will be constructed parallel to the existing one over a 2-kilometer stretch near the collapse site. This dual-pipeline system will facilitate maintenance without disrupting operations. The project, estimated to take 5 to 7 years, may extend to downstream sections, though costs and timelines for expansion remain undetermined.
Professor Hiroaki Morita of Nihon University, leading the expert committee, supports the plan, emphasizing its necessity for long-term maintenance.
For more details, visit the Tokyo Shimbun article.
