*This article is based on information as of January 2026, and references historical documents and the latest data from the Ministry of Land, Infrastructure, Transport and Tourism and the Ministry of Health, Labour and Welfare.

1. How the pandemic changed cities: Lessons from London's "Great Stink"

Let's turn the clock back to the 1850s. London, the epicenter of the Industrial Revolution, was thriving as the world's largest metropolis with a population of over 2.5 million. However, its reality was a pitiful state that could be described as a "glorious slum."

The city's metabolic capacity - its ability to process excrement - was completely overwhelmed by the rapidly growing population. At the time, London did not have a modern sewer system, and people collected waste in cesspools beneath their homes, which they then manually pumped out or simply dumped onto the streets or into storm drains.

As a result, the Thames, London's main river and drinking water source, had become a huge wastewater recycling system. Then, cholera, a deadly infectious disease originating from the Ganges River basin in India, struck.

"Location" Kills: John Snow and the Broad Street Pump

Cholera is a disease that causes severe diarrhea and dehydration within just a few hours of onset, leading to death due to the loss of fluids throughout the body. The rapid progression of the disease and the unknown cause of its spread led people at the time to fear it as the "invisible Grim Reaper."

At the time, the medical community was dominated by the "miasma theory," which held that disease was spread by "bad air" emanating from decaying matter. However, there was one doctor who boldly challenged this established theory: John Snow, the father of modern epidemiology.

When a cholera epidemic erupted in Soho in 1854, Snow suspected that the cause was not the air but the water. He used a groundbreaking data visualization technique at the time, plotting the locations of deaths house by house on a map.

After investigating, Snow discovered a certain fact: the deaths were concentrated among users of a particular well: the "Broad Street Pump."

"Remove the pump handle."

The epidemic was dramatically contained the moment Snow persuaded the local government to physically stop using the pumps. This marked a historic turning point in urban public health management, marking a paradigm shift from vague "air purification" to scientific "water source management."

The Great Stink that Moved Congress

However, scientific discoveries alone did not lead to the huge budget required for urban renovation. Ironically, it was the "discomfort" that struck politicians themselves that motivated them to undertake such a project.

In the summer of 1858, London was hit by a record heat wave. The heat wave caused a huge amount of sewage to pile up in the River Thames, causing it to rot and ferment, filling the whole of London with an unbearable stench. This is what has become known as the "Great Stink."

In the Houses of Parliament on the River Thames, MPs debated with handkerchiefs over their noses, soaked curtains in chloride of lime (a disinfectant) to stave off the stench, and even considered evacuating the building. Fearing for their lives and noses, Parliament passed the bill in just 18 days and authorized a massive sum of money (the 1858 Act gave them borrowing powers of up to £3 million) that rivaled the national budget at the time.

2. The Underground Revolution: Bazalgette's "Arteries" and "Veins"

In response to this crisis, Chief Engineer Joseph Bazalgette presented an ambitious blueprint to completely reshape London's underground.

Central to his plan was the concept of "Intercepting Sewers," a system in which the numerous small drainage channels flowing into the Thames would be "intercepted" by a huge main sewer system running parallel to the river, which would use gravity to transport wastewater downstream to remote areas rather than dump it into the river.

Bazalgette used 318 million bricks to lay a sewer network stretching 1,800 km in total. He also employed pioneering methods for modern integrated infrastructure development, filling in the marshes of the Thames to house the sewer pipes, building a new road (the Embankment) on top of it, and then laying the world's first subway underground.

The effect was dramatic. Below is an image of the change in the number of cholera deaths before and after the sewerage system was installed.

3. "Korori" in Japan and the Water Supply System in the Early Modern Period

Given this background, modern urban planning in Japan began with the development of vital infrastructure, namely the water supply system, rather than the construction of roads and squares as in Europe and the United States.

The pioneer of this was the Yokohama Waterworks, completed in 1887 (Meiji 20). Under the direction of British engineer Henry Spencer Palmer, this project drew water from the upper reaches of the Sagami River, and was Japan's first modern waterworks, becoming a model for subsequent urban sanitation projects.

Hokkaido: Infrastructure as a Breakwater

The situation was dire in Hokkaido as well. Hakodate and Otaru, which served as hubs for the mainland, were on the front lines of cholera, bringing people and goods with them. During the 1886 epidemic, many people died in Hakodate.

In response to this, Hakodate completed a modern waterworks system, the second in Japan after Yokohama, in 1889. This was an investment that should have been prioritized above all else, as Hakodate at the time was to function as an international trading port and as a "breakwater against epidemics" for the development of Hokkaido.

4. Modern Issues: The Cry of Aging "Invisible Assets"

Thanks to the great investments made by our predecessors, modern Japan has one of the world's best public health standards. There are very few countries in the world where you can drink the water straight from the tap.

However, we are now facing a new, more static and serious crisis: aging infrastructure.

Sewerage and water pipes that were laid all at once during the period of rapid economic growth are now all reaching the end of their service life (generally 50 years). The graph below shows a forecast of the future length of sewerage pipes 50 years after construction.

If the challenge in the 19th century was "how to create (construction)," our challenge in the 21st century has shifted to "how to protect and wisely fold (maintain and reorganize)."
It is no longer possible to upgrade all infrastructure equally, as was the case in the days of steady growth. We are being forced to make the painful decision to "select and focus."

5. Suggestions for regional revitalization: A perspective from Toyako Town

So what does this historical context suggest for a place like Toyako Town, Hokkaido?

The sewerage coverage rate of Toyako Town is approximately 86.0% (as of the end of fiscal year 2022). This is significantly higher than the national average (approximately 81%) and compared to towns and villages of similar size in Hokkaido. One of the reasons for this is likely that Toyako Town has maintained a high level of awareness of environmental improvement as the host city of the 2008 Hokkaido Toyako Summit.

However, the cost of maintaining the pipelines connecting settlements scattered over a vast area is enormous. In addition, as the town is located at the foot of Mount Usu, an active volcano, there is also the risk of pipeline damage due to tectonic movements.

What is needed here is a perspective that reconsiders "clean water" not simply as a sanitation facility, but as a "capital" that creates economic value.

Downsizing: Evolution

In a situation of population decline, it will be necessary to shift from laying pipes to treating wastewater at each household (using septic tanks, etc.), in other words, to downsize infrastructure. This is not a "setback."

In the event of a disaster (especially a crustal movement such as an eruption), a networked infrastructure that is connected like a mesh is vulnerable as a disruption in one area can spread to the entire system.In contrast, an autonomous decentralized system is resilient from the perspective of risk dispersion.

Humanity once centralized city management to prevent cholera, but perhaps it is now time for us to once again embrace the wisdom of "decentralization" for the sake of sustainability.

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