In 2017, Virginia sank up to 20,000 tons of a demolished bridge, creating a concrete haven for fish beneath Chesapeake Bay

Somewhere down below the Chesapeake Bay, you can find a stretch of highway that has fish living inside it. Well, not just metaphorically. Old bridge girders, piles, and concrete culverts lie at the bottom of the bay, now full of barnacles and providing a home to sea bass and flounder as if it were an apartment complex. Sounds like a recipe for the next episode of your favorite local TV news, but this is actually a rather popular case of marine science and has been unfolding along the coast of Virginia for quite a while.

The story goes back to 2017, when the old Lesner Bridge that spans the Lynnhaven Inlet was decommissioned and replaced with a newer, more modern one. Instead of sending the debris to the dump, engineers had seen 20,000 tons of concrete being dropped into the bay to build an artificial reef called the "Cabbage Patch," detailed by Clark Nexsen, the company that built the replacement bridge. Even better, the Virginia Marine Resources Commission (VMRC) sent some of the old girders to Virginia Tech to conduct some tests on their strength so as to determine how much more weight the aging bridges in the area could support.

The bridge that refused to just disappear


And while it may sound like a rather pleasant story from nine years back, this has become the norm in Virginia, it seems. Virginia's huge Hampton Roads Bridge-Tunnel project has been deploying an estimated 100,000 tons of demolished concrete, including girders, piles, and entire bridge segments, onto artificial reef sites in the Chesapeake Bay, as per the reports by WHRO, quoting VMRC reef specialist Hunter Smith. The material deployment was already fully approved and actively underway by mid-2026.

This is five times the amount that the Lesner Bridge project dumped, and is scattered across new sites like Bluefish Rock Reef and Back River Reef, with more expected to come as construction goes on. "You just put it down, and nature takes care of the rest," summarizes Smith.

Does dumping concrete in the ocean actually work?

That’s an interesting point and one that marine biologists have already explored in marine biology. According to a study by NOAA, in which 39 peer-reviewed studies comparing artificial reefs to natural ones across the world were combined into a single meta-analysis, artificial reefs appear to host fish in density, diversity and biomass close to that of natural reefs, although not always; though the researchers made it clear that this doesn’t just happen automatically and varies based on the location, depth, and materials used in the construction of the reef.

In a separate study carried out using sonar to examine 31 reef structures in North Carolina, NOAA found something else: fish density is more dependent on a reef's vertical structure than its horizontal size, meaning that a tall and uneven jumble of debris from a broken bridge is more likely to attract fish than a flat slab.

The part that doesn't make it into the press release

This is the skeptical footnote that is worth remembering. In accordance with a study published by PLOS ONE, which analyzed a reef composed of more than 4,000 concrete culverts near Port Mansfield, Texas, an excessive density does not lead to the best results; rather, an average amount of material proved to work better than both low and high densities. It is still not clear whether such artificial reefs increase the total number of fish in general or just attract them from their natural habitat to a more comfortable place. The VMRC does check all the concrete donations for possible coatings or contaminants before sinking them into the sea.

Why this should register with us

For a generation raised with “circular economy” being thrown around as a buzzword, this is the practical and gritty form of that concept, as opposed to being used for landfill after its initial purpose has expired. It’s certainly not a climate magic bullet, and that’s the first thing that even the scientists who discovered this will admit to. However, it’s a refreshing case where recreational fishing, marine biology, and construction waste disposal come together on the same page.