Avoiding being in the water might not have been, but sewage runoff during rains has been in most older cities; it’s a result of having combined sewers. Cities started moving to having seperate sewage and rainwater systems some time back, but older cities won’t do that.
Over here in the US, cities in the western part of the US – the youngest ones – generally don’t see it, but ones in the eastern part still do. In Europe, where cities have generally been around for a while, it’s a thing.
A combined sewer is a type of gravity sewer with a system of pipes, tunnels, pump stations etc. to transport sewage and urban runoff together to a sewage treatment plant or disposal site. This means that during rain events, the sewage gets diluted, resulting in higher flowrates at the treatment site. Uncontaminated stormwater simply dilutes sewage, but runoff may dissolve or suspend virtually anything it contacts on roofs, streets, and storage yards.
Combined sewers can cause serious water pollution problems during combined sewer overflow (CSO) events when combined sewage and surface runoff flows exceed the capacity of the sewage treatment plant, or of the maximum flow rate of the system which transmits the combined sources. In instances where exceptionally high surface runoff occurs (such as large rainstorms), the load on individual tributary branches of the sewer system may cause a back-up to a point where raw sewage flows out of input sources such as toilets, causing inhabited buildings to be flooded with a toxic sewage-runoff mixture, incurring massive financial burdens for cleanup and repair. When combined sewer systems experience these higher than normal throughputs, relief systems cause discharges containing human and industrial waste to flow into rivers, streams, or other bodies of water. Such events frequently cause both negative environmental and lifestyle consequences, including beach closures, contaminated shellfish unsafe for consumption, and contamination of drinking water sources, rendering them temporarily unsafe for drinking and requiring boiling before uses such as bathing or washing dishes.
Mitigation of combined sewer overflows include sewer separation, CSO storage, expanding sewage treatment capacity, retention basins, screening and disinfection facilities, reducing stormwater flows, green infrastructure and real-time decision support systems.
This type of gravity sewer design is less often used nowadays when constructing new sewer systems. Modern-day sewer designs exclude surface runoff by building sanitary sewers instead, but many older cities and towns continue to operate previously constructed combined sewer systems.
Some US cities have undertaken sewer separation projects — building a second piping system for all or part of the community. In many of these projects, cities have been able to separate only portions of their combined systems. High costs or physical limitations may preclude building a completely separate system.
Increased heavy rain events have been happening due to global warming, which has exacerbated it. 2010, 13 years ago, was a significantly drier year, and subsequent to that, there has been more rainfall then prior, and it has been more concentrated in heavy rain events. Heavy rain events are what drive the sewage runoff.
Between 2001 and 2022, the average rainfall in the United Kingdom varied greatly. In 2010, rainfall dropped to a low of 1,020 millimeters, which was a noticeable decrease when compared to the previous year. However, the following year rainfall increased significantly to a peak of 1,889 millimeters. During the period in consideration, rainfall rarely rose above 1,500 millimeters. In 2022, the annual average rainfall in the UK nearly reached 1,321 millimeters.
The latest State of the UK Climate report indicates the UK has become wetter over the last few decades, although with significant annual variation. 2011-2020 was 9% wetter than 1961-1990.
The number of days where rainfall totals exceed 95% and 99% of the 1961-1990 average have increased in the last decade, as have rainfall events exceeding 50 mm. Both these trends point to an increase in frequency and intensity of rainfall across the UK.
increases in heavy rain events all over Europe did not cause such fecal mater contamination events in countries other than the UK.
There have also been heavier rainfall events in places in Europe, though not all of Europe is expected to see overall precipitation increase. Germany, Belgium, and the Netherlands had serious flooding that made the news in 2021:
At least 70 people have died in Germany and Belgium after record rainfall caused rivers to burst their banks.
Most of the victims were in Germany, but at least 11 have died in Belgium, with more reported missing.
The German states of Rhineland-Palatinate and North Rhine-Westphalia were worst hit, but the Netherlands is also badly affected.
More heavy rain is forecast across the region on Friday, while local officials have blamed climate change.
Armin Laschet, the premier of North Rhine-Westphalia, blamed the extreme weather on global warming during a visit to a hard-hit area.
“We will be faced with such events over and over, and that means we need to speed up climate protection measures… because climate change isn’t confined to one state,” he said.
Flooding events over the past 12 months include devastating flooding in central Europe during summer 2021, flooding of the London underground in July 2021 and in Zhengzhou, China in the same month. In the central Europe event, some parts of Western Europe received up to two months worth of rainfall in two days. A recent climate attribution study has shown that climate change made the one day rainfall in this region more intense - increasing the rainfall by between 3 and 19%.
The UK, however, is an area that has seen net precipitation increases and is expected to see considerably more moving forward:
In the future, we project the intensity of rain will increase. When we talk about intensity, we mean how heavy rainfall is when it occurs. In the summer, this could increase by up to 20%. In winter, it could increase by up to 25%.
Hourly rainfall exceeding 30mm per hour is a threshold used by the Met Office and the Environment Agency Flood Forecasting Centre to issue flash flood alerts. By 2070, we project we will meet this threshold twice as often as we did in 1990.
A greater risk of flooding will have large impacts, both on the environment and in our daily lives.
One could go read articles on why the UK is one of the places that is expected to see that precipitation increase, but I’d guess that it has a lot to do with the fact that the UK is a rainy place in general compared to much of Europe, gets the moist air coming directly off the Atlantic along with her sister Ireland, and is far north enough of the equator to catch the westerlies. In general, the global expectation is that rainier places will also be the places that tend to see the largest increases in precipitation from climate change.
EDIT: Though California, where I am, is mostly fairly arid and is expected to see an increase in heavy rainfall events due to IIRC the angle of storm travel being altered by climate change; we had a lot of extremely heavy rain and snow last winter and that is expected to increase; just as you get rainfall from moist air off the Atlantic, we tend to get it off the Pacific:
How California’s weather catastrophe turned into a miracle
Gushing waterfalls, swollen lakes and snow-covered mountaintops transformed the state’s arid landscapes.
FRESNO, Calif. — Californians were preparing for another year of unrelenting drought in 2023. Instead, they got months of incessant rain and some of the heaviest snowfall they have ever seen.
Research by UCLA climate scientists, published today in Nature Climate Change, projects that the state will experience a much greater number of extremely wet and extremely dry weather seasons — especially wet — by the end of the century. The authors also predict that there will be a major increase in the likelihood of severe flooding events, and that there will be many more quick changes from one weather extreme to the other.
Avoiding being in the water might not have been, but sewage runoff during rains has been in most older cities; it’s a result of having combined sewers. Cities started moving to having seperate sewage and rainwater systems some time back, but older cities won’t do that.
Over here in the US, cities in the western part of the US – the youngest ones – generally don’t see it, but ones in the eastern part still do. In Europe, where cities have generally been around for a while, it’s a thing.
https://en.wikipedia.org/wiki/Combined_sewer
Yet in the UK things were improving until 13 years ago when they started getting worse.
They didn’t suddenly combine the running water and sewage disposal in a single system 13 years ago so clearly something else made the difference.
Increased heavy rain events have been happening due to global warming, which has exacerbated it. 2010, 13 years ago, was a significantly drier year, and subsequent to that, there has been more rainfall then prior, and it has been more concentrated in heavy rain events. Heavy rain events are what drive the sewage runoff.
https://www.statista.com/statistics/322810/average-rainfall-in-the-united-kingdom-uk/
https://www.metoffice.gov.uk/research/climate/understanding-climate/uk-and-global-extreme-events-heavy-rainfall-and-floods
Yet, strangelly, increases in heavy rain events all over Europe did not cause such fecal mater contamination events in countries other than the UK.
Must be some kind of special British rain… (Maybe its yellow and only rains down on the plebs, not the upper classes)
There have also been heavier rainfall events in places in Europe, though not all of Europe is expected to see overall precipitation increase. Germany, Belgium, and the Netherlands had serious flooding that made the news in 2021:
https://www.metoffice.gov.uk/about-us/press-office/news/weather-and-climate/2021/future-extreme-rainfall-more-extreme-than-first-thought
The UK, however, is an area that has seen net precipitation increases and is expected to see considerably more moving forward:
https://www.metoffice.gov.uk/weather/climate-change/climate-change-in-the-uk
One could go read articles on why the UK is one of the places that is expected to see that precipitation increase, but I’d guess that it has a lot to do with the fact that the UK is a rainy place in general compared to much of Europe, gets the moist air coming directly off the Atlantic along with her sister Ireland, and is far north enough of the equator to catch the westerlies. In general, the global expectation is that rainier places will also be the places that tend to see the largest increases in precipitation from climate change.
EDIT: Though California, where I am, is mostly fairly arid and is expected to see an increase in heavy rainfall events due to IIRC the angle of storm travel being altered by climate change; we had a lot of extremely heavy rain and snow last winter and that is expected to increase; just as you get rainfall from moist air off the Atlantic, we tend to get it off the Pacific:
https://newsroom.ucla.edu/releases/california-extreme-climate-future-ucla-study