Swirling the drain: The climate-driven effort to fix sewers

Let’s talk about sewers.

No, sewers are not what readily come to mind when thinking about climate change, and that’s made abundantly clear by a new poll on climate issues. The United Nations Development Program (UNDP) and University of Oxford teamed up to ask 1.2 million people from 50 countries what their climate policy priorities are, and sewers didn’t make the top of the list.

People chose forest and land conservation, renewable energy and climate-friendly farming as the top three picks. But they also chose “investing more in green businesses and jobs” next, and that’s an area where water and waste infrastructure should get top billing.

The most recent issue of Climate Risk Management explains why with insights from a research team in New Zealand. Sea-level rise, more frequent episodes of extreme rainfall, more intense storms, and changing wind and wave patterns are stressors that can push these systems beyond their original design capacities – and those designs may be a century old or more. A lot more.

“Climate change adaptation is increasingly being recognized as important for managing the performance and location of wastewater systems, which means that understanding the science and local knowledge is key for adaptation strategies,” note the paper authors.

When these systems fail in the face of climate pressure, the damage isn’t limited to mechanical components. Sewers have been critical to protecting public health for centuries; even now, during the COVID pandemic, cities from Paris to New York are monitoring their wastewater for data on COVID infection in their populations. And one need only look at communities around the world where millions of people still live without them to see the public health consequences.

Wastewater systems play a role in preserving safe water resources, in overall economic development and in a range of other priorities. So most people may not think about it much but planners do, and the United Kingdom, with some 240,631 kilometers of frequently polluted river, is the latest nation to implement a data-driven plan to protect water infrastructure from rising threats.

The UK announced last week that its water authorities will invest £1.1 billion (US$1.5 billion) over the next five years to address challenges climate change has already created, especially the damage from storm overflows that combine wastewater and storm runoffs into overstressed systems. Nearly 800 improvement projects in the UK are planned through 2025.

“Storm overflows were designed to be used during extreme weather to prevent sewers becoming overloaded with a combination of sewage and rainwater, releasing diluted wastewater into rivers rather than letting it back up into people’s homes,” the UK government explains. “However, climate change has led to increased rainfall and water infrastructure has not kept pace with development growth over decades.”

Christine McGourty, the head of Water UK, said the country’s experience with flooding and damage wrought by Storm Christoph in January illustrates the problem. McGourty and other partners of the UK’s Storm Overflows Taskforce said the government will require its water companies to produce drainage and sewer management plans to help protect the infrastructure assets as well as the environment.

“I have been shocked to discover the extent of sewage routinely spilled in our rivers,” said MP Philip Dunne, who introduced legislation on sewers last year and has championed the cause.

“Poor water quality has a very damaging impact on aquatic species which depend on clean rivers, and risks healthy enjoyment of our rivers by the public. I am really pleased this government has recognized that this has got to change.”

Image: Paris Sewer Museum file

Photo by Ignis/Wikimedia Commons (CC BY-SA 3.0)