Depopulation’s impact on infrastructure

Cities throughout the United States may look very different in the future as many are losing residents. By the year 2100, researchers predict that approximately half of the 30,000 cities in the U.S. will lose up to a quarter of their residents, which will have a major impact on infrastructure and the remaining population.

The findings were published in the journal Nature Cities under the title “Depopulation and associated challenges for US cities by 2100” by Professor Sybil Derrible, Assistant Professor Lauryn Spearing, and PhD candidate Uttara Sutradhar, all from civil, materials and environmental engineering at UIC.

“For cities, having a declining population usually means socioeconomic and infrastructure challenges to accommodate the remaining population,” said Derrible, who is the director of the Complex and Sustainable Urban Networks Lab at UIC.

The research was initiated by the Illinois Department of Transportation to understand how depopulation would impact transportation infrastructure in Illinois.

“We surveyed the cities in Illinois that are depopulating and tried to identify the common problems and found that these problems are not the same,” Sutradhar said.

The issues vary depending on the proximity to Chicago or major cities where there are more travel options. People living further away from large cities had more problems because they did not have as many modes to travel to basic services.

“In Illinois, approximately 70% of cities are already depopulating. They have roads, buildings and other infrastructure that are underutilized,” she said.

As the researchers dove deeper into the data, they decided to look at cities throughout the U.S. to find the extent of the problem. They used census data from 2000, 2010 and 2020 to find population trends and combined it with data that anticipates different climate change scenarios to create their analysis. They found that 43% of cities in the U.S. are losing population, 40% are gaining and the remaining have fluctuating trends.

A significant population decline will bring unprecedented challenges, which could result in disruptions to basic services like transit, clean water, electricity and internet access. At the same time, population increases in resource-intensive cities and suburban areas have the potential to divert resources from the depopulating areas, further exacerbating their challenges.

“We plan to find out how much infrastructure is going to be underutilized or even abandoned when people leave those places,” Sutradhar said. “All this infrastructure is built for a certain number of people, and when people move out of these places, infrastructure deteriorates, which becomes a hazard.”

In addition, infrastructure maintenance will be needed, and when there are fewer people there is less revenue and infrastructure maintenance becomes a big issue. In the U.S., the infrastructure is already aging and in need of maintenance. It’s going to be a burden on the people who remain in the depopulating cities.

“Having an estimation of future population trends can assist authorities in better planning and designing cities and their infrastructure systems for depopulation,” Derrible said. “We need to shift away from growth-based planning, which will require a significant cultural shift in the planning and engineering of cities. But we should not fear depopulation. Instead, we should see it as an opportunity to rethink how we do things.”

— Written by David Staudacher