Carolina Curious: How has the Salem Lake construction impacted local biodiversity?

Since early September, Salem Lake's water levels have been about 10 feet lower than normal as construction crews are working on the boat ramp and retaining walls.

For people, this just means a few months without water activities. But Kernersville native and frequent Salem Lake visitor Elizabeth White wants to know how the construction will impact the surrounding nature life.

"I want to know if the draining of Salem Lake, and also the flooding of Salem Creek is having any effect on the biodiversity of the plants and the animals that live in that area. And also what does that mean for our drinking water, since we get our drinking water from Salem Lake as well?"

In the 2018 election, Winston-Salem voters approved a bond referendum that allotted $3.7 million toward Salem Lake improvements. And in August 2021, Phase II of these improvements began. The projects planned include renovations of the shoreline bulkhead, rebuilding the boat ramp, adding additional kayak storage, creating boat slips and building a picnic shelter near the playground. 

Bobby Hege, the lakes program supervisor for the City of Winston-Salem Recreation and Parks, is overseeing the construction. He said that the construction crews slowly allowed water to flow from the lake through an open valve on the dam into Salem Creek. This process prevented flooding along the creek and drastic changes in the lake.

“It hasn't really had a negative effect on the animal life. The water being drawn down does compile and make all the fish closer together, which for the big fish they get real happy. Some of the smaller baitfish, maybe not so much,” says Hege.

Hege also mentioned that the lower water levels have attracted more freshwater birds, like egrets and herons to the area. 

Wake Forest University professor of biology Miles Silman echoed Hege and said that many Piedmont area lake ecosystems are very resilient when it comes to disturbances because Salem Lake is manmade.

“If you think about the amount of flooding that comes down a river due to a hurricane, or a very large rainstorm event, those create tremendous volumes of water. I suspect similar to the kinds of water volumes that were put out by releasing the water to draw down the lake, if not more. The organisms that live in that water are used to having those kinds of disturbances, particularly when you get to larger streams,” Silman says.

And in terms of the water releasing into Salem Creek, Silman says it is doing more good than harm.

“One of the bad things that happens when you put a bunch of dams in the system is that you eliminate the flood pulses. And what happens then is that vegetation can grow into areas where they normally wouldn't be able to live. It can change the entire way the stream looks, what they call the morphology of the stream,” Silman added.

Urbanization can also affect the morphology of streams, and this is evident in the case of Salem Creek. If you were to look at old mapping records of Winston-Salem dating back to when the Moravians settled across Forsyth County, you would see that the streams of today look much different from the 18th century. This is what Wake Forest assistant professor of engineering Lauren Lowman and student Sam Matterazzo saw for themselves. 

“The reason why they chose this area was because it had a lot of natural springs and it had a lot of underground stream networks to provide these natural springs. They came here because we are so rich in water. And as time went on and we moved towards industrialization and building this urban center, those streams got in the way. So we built over them,” Lowman says.

“Now we have a lot of asphalt and concrete and building groups. Those are all impermeable surfaces, which means that the water can't get absorbed into the soils, so instead it runs off into our streams. So a lot of these streams, like Salem Creek, like some parts of Muddy Creek, you'll see quite a bit of stream bank erosion. So when it rains, the water only has so many places it can go,” Lowman continued.

Lowman is talking about the Salem Creek Greenway, where portions of the pathway are subject to constant flooding. Matarazzo, a senior Wake Forest student who has been working with Lowman since his freshman year, says there are ways to mitigate flooding. 

“You select a section of stream, usually a couple miles at a time, and you basically redig the channel back to the most natural possible way," Matterazo says. "You're going to use native plants, obviously, like they grow here for a reason. You're going to want to use those as a way to just act as a natural sponge, just to absorb. The Salem Creek Greenway is built almost right along the creek. But ideally, you'd have a riparian area where you have all that vegetation between the creek and the greenway so that it gives a huge natural buffer for it to flood.”

This process is called rewilding. But the chances of this happening at Salem Creek are slim as those natural buffer zones have already been built over. This would require extensive construction in a narrow area. However, this does mean that the current Salem Lake construction and draining is not having an impact on the flooding habits of Salem Creek.

The construction is also having no effect on the city of Winston-Salem's water supply. Bill Brewer, water treatment superintendent for Winston-Salem, says that no water from Salem Lake is being taken to treatment facilities while the construction is ongoing.

“Our system is very resilient in the respect that we have three water plants. And we also have ample capacity in the Yadkin River that we can draw from just in this type of scenario,” Brewer says.

So to answer Elizabeth's question, the impacts on biodiversity are minimal and the drinking water supply is still safe. And while the water levels returning to normal depends entirely on the amount of rain this area will get, the lake will hopefully bounce back by the end of the year. There is no reason to worry. Unless you are a small baitfish.