Pennsylvania has over 180 levees that span approximately 155 miles (255 kilometers) and keep its rivers from flooding. They protect about 158,000 people and US$26.2 billion in property across the state, according to the U.S. Army Corps of Engineers.

However, those levees are aging, and funding to maintain and improve them is becoming scarcer.

At the same time, extreme weather is becoming increasingly frequent and severe.

As a geotechnical engineer and geohazards researcher, I study how levees respond to flooding. I also help develop solutions to evaluate, manage and improve aging levee infrastructure.

These solutions are more important than ever as Pennsylvania continues to see record rainfall this season.

Levees are earthen embankments positioned parallel to a river that effectively raise the height of the banks of the river to prevent overflow when the river swells.

Typically, levees are designed to prevent flooding from a particular-size flood. Often, that’s a flood that has a 1% chance of occurring in any given year.

Levees can be breached when water flows over the top during flooding. They can also fail due to erosion, water seeping through or under the embankment, and partial collapse of the embankment before floodwater reaches the top.

In Pennsylvania, flooding is a frequent and damaging natural hazard.

The state’s 86,000 miles (138,000 kilometers) of rivers and streams commonly surge under heavy rains and snowmelt. Major population centers Philadelphia and Pittsburgh both are flanked by rivers. And although Pennsylvania is not thought of as a coastal state, it can be significantly impacted by remnants of hurricanes and tropical storms.

Pennsylvania’s 2023 State Hazard Mitigation Plan has recorded almost 5,000 flood events in the state since 1996. The National Flood Insurance Program has paid over $1 billion in claims to property owners in Pennsylvania over that same time period.

Aging infrastructure and growing costs

The Flood Control Act of 1936, signed by President Franklin D. Roosevelt as part of his New Deal agenda, was partially motivated by devastating flooding in Pennsylvania that year. The legislation allocated funding for the construction of many of Pennsylvania’s levees. As a........

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