# 2025 Study: New Orleans Sinking Up to 2 in/yr | New Orleans Concrete Leveling

> A 2025 Tulane study in Science Advances found parts of New Orleans and its $15B flood defenses sinking up to 47 mm a year. What it means for slabs at home.

URL: https://concretelevelingneworleans.com/blog/new-orleans-flood-defenses-sinking-2025-study/

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# Study: parts of New Orleans and its flood defenses are sinking up to 2 inches a year

By New Orleans Concrete Leveling · September 24, 2026

[New Orleans Concrete Leveling](https://concretelevelingneworleans.com/) tracks subsidence research because it’s the reason most concrete in this city sinks. The latest major study landed in June 2025.

## What the study found

Researchers from Tulane University’s Department of River-Coastal Science and Engineering — lead author Simone Fiaschi, with Prof. Mead Allison — analyzed satellite radar data from **2002 to 2020** and published the results in _Science Advances_ (Vol. 11, Issue 26, June 28, 2025), as reported by [ScienceDaily](https://www.sciencedaily.com/releases/2025/06/250627234122.htm). Key findings:

-   Some neighborhoods and wetlands are sinking **more than 1 inch a year**.
-   The fastest areas reach **up to 47 millimeters — nearly 2 inches — a year**.
-   Parts of the **Hurricane and Storm Damage Risk Reduction System (HSDRRS)**, the $15 billion post-Katrina levee and floodwall network, are themselves sinking, and some floodwall sections are losing elevation faster than sea level is rising.

“In a city like New Orleans, where much of the land is already near sea level, even minor drops in elevation can increase flood risk,” Fiaschi said.

## How it fits with earlier numbers

The finding lines up with what the City and NASA have reported. The [City of New Orleans](https://ready.nola.gov/hazard-mitigation/hazards/subsidence/) puts the city-wide average at about 0.2 inches a year, with parts of the city above 0.8 inches. NASA JPL’s 2016 study found up to 2 inches a year in industrial areas such as Michoud and Norco ([NASA JPL](https://www.jpl.nasa.gov/news/new-study-maps-rate-of-new-orleans-sinking/)). The new study extends the record to 2020 and puts the flood defenses themselves on the map.

## What it means at home

The headline is about levees, but the mechanism is the same one under your driveway: **uneven sinking**. Ground that drops at different rates a few blocks — or a few feet — apart is what opens the lip between a driveway and a carport, pulls a walk away from a raised porch, and tips a patio back toward the house.

Three practical takeaways:

1.  **Expect flatwork to keep moving.** A leveled slab rides the ground; what makes it drop suddenly is water washing out support. See [will my slab sink again?](https://concretelevelingneworleans.com/guide/will-my-slab-sink-again/)
2.  **Control the water.** Downspouts away from slab edges and sealed joints matter more on moving ground.
3.  **On the fastest ground, think about weight.** Lighter polyurethane foam adds far less load than slurry. See [foam vs mudjacking](https://concretelevelingneworleans.com/guide/foam-vs-mudjacking/).

The full local explanation is in [why concrete sinks in New Orleans](https://concretelevelingneworleans.com/guide/why-new-orleans-concrete-sinks/). For a free estimate on a slab that’s moved, call [(504) 517-8336](tel:+15045178336).

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