Go to any nearby river, stream or waterway and you’re bound to eventually run into a culvert. Most people don’t pay much attention to culverts and therefore, have no idea the problems they cause to aquatic organisms and wildlife.

But for Mercy Melo, Pennsylvania Game Commission’s Environmental Education Specialist of the Northcentral Region, she knows all too well the damage and issues culverts cause throughout the region.

“I feel like a lot of people don’t know that culverts are problematic and they’re sort of everywhere. The biggest thing is they impede the movement of aquatic organisms. The most common example is fish,” Melo said. “Think about little brook trout that would be in these streams. If a culvert’s there, there’s three main things that will prevent a fish from going upstream.”

Those issues are the height of a culvert and waterfalls; bottom material the culverts are made out of; and water flow.

Culverts are simply structures which enable water to get past an obstacle or waterway, and generally are made from pipe or concrete. Both of which are issues for aquatic organisms.

“Fish are as affected by those, but other organisms like crayfish can’t walk over a culvert,” Melo noted.

The issue of culverts is something that has led the Game Commission to teaming up with the Aquatic Organism Passage Program, or AOP, to remove problematic culverts and replace them with bridges. This will allow for waterways to flow naturally while still allowing for driving access.

With a bridge opposed to a culvert, the stream gets restored to what its natural state was and people can still drive over it without any issues or disturbances to the ecosystem.

The issues with culverts is something that Melo noted is fairly recent, but something the Game Commission is eager to get started with. Melo sees this as somewhat of being guinea pigs in terms of getting things started elsewhere outside the north central region of Pennsylvania.

“It’s definitely a recent discovery and, in terms of the Game Commission, the north central region is our pioneering region. Others aren’t yet associated with the AOP program,” Melo said. “We’re kind of Guinea pigs to work it out. Looking at other states, we’re sort of a pioneer considered to others.”

And getting the word out about culvert replacement and spreading is what Melo is optimistic about.

“We’re hoping for sure (this spreads). We’re not just pioneering the idea, but the process, step by step. I don’t want to say we’re laying the foundation, but we’re kind of laying the foundation of having other groups join in the protocol and make the simple change to help organisms,” Melo said.

Taking out a culvert and adding in a bridge instead isn’t too tough of a process. Melo joked that her and the Game Commission have it somewhat down to a science at this point.

“I was able to observe an entire process and it only took four days,” Melo said.

Melo described the process as fairly straightforward as they pull up the existing culvert with an excavator, restore the stream to its natural size and then use concrete and steel I-beams to help construct the bridge with wood on top which eventually becomes a deck.

They then restore the stream bed, matching the shape and size with what was above and below the culvert so that there’s no bottleneck that can happen with a culvert.

“The first one or two big storms might wash some of that sediment down, but in general, once a bridge is put in place, all that water can move as naturally as it would have even if that bridge wasn’t there,” Melo said.

Another benefit with a bridge is that it’s elevated above the ground and above the base of the stream bed, meaning that in the event of a huge storm with obstacles traveling down the waterway — such as a large branch — it won’t get stuck and cause a flow issue or flooding.

“You’ll see sticks or full-size trees just crossing over water and creating a physical barrier (with culverts),” Melo said. “Bridges never produce that (problem).”

So far, Melo and the Game Commission have completed five projects that just started in the last year, and are planning things for 2024 and working on getting permits to continue to replace culverts.

One of the biggest issues regarding the culverts were trouts and their migrations. Since culverts create issues, the bridges will help prevent anything regarding spawning or migrating.

“If they’re not able to swim upstream and get past a culvert or barrier, they just can’t connect with other populations on the other side of that barrier,” Melo said. “Similar with food. They have to be able to move.”

Melo said that in terms of replacing the culverts, they survey for trout and look to see if it’s an important stream for trout ecology or if it’s a great spawning area.

“We avoid doing any work during spawning season or we’ll be extremely careful in preparation to make sure we keep conditions as perfect as possible, especially for our native brook trout,” Melo said. “We haven’t noticed anything negative with trout spawning, but we are extremely careful to prevent that in the future.”