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Groundwater rise as a result of climate change poses a significant threat to coastal cities, says University of Rhode Island assistant professor of geosciences Christopher Russoniello. Russoniello and colleagues recently published a commentary piece highlighting hazards that are often overlooked in urban infrastructure.

featured in the journal Nature Cities, highlights three hazards in infrastructure that often go undiscussed—water table rise, groundwater salinization, and compound man-made and climate-related groundwater changes. The existence of these hazards underscores the critical need for better monitoring and solutions to ensure safe and sustainable urban environments.

Affected infrastructure include roads, sewers, and septic systems; buried gas and electric lines; and building foundations. Other types of urban infrastructure are vulnerable to corrosion from saltwater intrusion, including buried pipes and tanks.

"I think we have come to an understanding that groundwater plays a bigger role in surface flooding and other hazards facing urban communities than initially thought," said Russoniello.

"A lot of the previous work into groundwater near the coast is focused on more rural conditions—such as how groundwater rise will impact septic systems or how it will impact natural settings someplace like the southern coast of Rhode Island."

Climate-related groundwater changes can impact a city's capacity to protect its infrastructure. Groundwater rise and salinization under coastal cities can damage buried infrastructure, impair wastewater systems, reduce surface drainage and render groundwater unsuitable for drinking.

Solutions could include: incorporating corrosion-resistant pipes or concrete reinforcement in areas at risk; enhancing subsurface drainage or dewatering systems; and designing pumping well placement and extraction schedules that limit these challenges. There are opportunities to monitor groundwater levels and salinity dynamics by using geophysical surveys and multilevel wells instrumented with electrical conductivity and water pressure sensors.

"With the data we have showing how these changes can affect our aging urban infrastructure as climate is changing and sea levels continue to rise, I hope that this will be a call to action and a call to make positive change," said Russoniello.

Russoniello is part of a team of researchers led by URI professor Emi Uchida to study flooding in the town of Warren, Rhode Island, supported by an NSF EPSCoR grant. The multi-state collaboration also includes researchers in South Carolina and Delaware.

Compared to sites in the other two states, Warren, which is more urban and doesn't rely on groundwater or septic systems, is a perfect example of how potential climate-related groundwater hazards may go overlooked until they start to impact infrastructure.

"We have social scientists, groundwater experts, and engineers all working collaboratively together to try to understand community concerns and priorities, and what different types of adaptation they may be able to implement."

Research findings could lead to updated guidelines, codes and materials that improve coastal urban infrastructure resilience to changing groundwater using nature-based or hard engineering-based solutions. New research programs that involve urban planning, social science, environmental science, civil engineering, materials science, coastal science and hydrogeology should be launched to advance understanding, prediction and prevention.