Sinkholes are draining a prized Lehigh Valley trout stream. Is nature to blame, or a nearby cement plant?

STOCKERTOWN, Pa. — Creeks usually babble, but the sound coming from a stretch of the Little Bushkill on a recent autumn afternoon had a deeper, more guttural tone. Water was cascading into a sinkhole some six feet deep, carving out rock and dirt beneath the bank.

“That wasn’t there a few days ago,” said Joe Baylog, president of the Forks of the Delaware Chapter of Trout Unlimited.

On the bank across from it, yet another sinkhole swallowed more of the Little Bushkill, cutting off its flow to the larger Bushkill Creek 20 yards downstream. The sinkholes had created such a vacuum, even some of Bushkill Creek’s water was running toward them, in the opposite direction.

Baylog and other fisherman believe those sinkholes and countless more in the two Northampton County creeks are caused by the Hercules Cement plant upstream. Founded in 1916, the company has changed the local geology, Baylog contends, because its deep limestone quarry drains the water table.

Daniel Nugent, a spokesperson for Buzzi Unicem, the Italian company that owns the plant, said various state and federal agencies have noted that the Lehigh Valley has the “highest natural sinkhole occurrences in the country and has experienced sinkhole formation for centuries.”

Every day, the plant pumps out 50 million to 55 million gallons of water from the quarry into Bushkill Creek, Nugent said. On two recent occasions, however, those pumps stopped moving water back into the creek — and suddenly, no more creek. On Oct. 15, the Bushkill dried out for several hours when temporary backup pumps at Hercules couldn’t maintain flow during planned pump maintenance. It’s still unclear how many fish were killed that day, Baylog said, because the creek still hadn’t recovered from a June outage that also dried it up and killed thousands of fish, including brown trout.

When the pumps went back on, Bushkill Creek — about 30 yards wide and a few feet deep in spots — flowed again.

With headwaters beginning on the slopes of Blue Mountain, the Bushkill continues 22 miles before converging with the Delaware River in Easton. Trout Unlimited, a nonprofit dedicated to freshwater stream preservation, designates the stream as a “high quality cold water fishery,” with portions considered “Class A” trout waters by the Pennsylvania Fish and Boat Commission.

Buzzi Unicem said drought conditions on Bushkill Creek exacerbated the problem on Oct. 15. According to a report on LehighValleyLive.com, Hercules’ environmental manager, Keith Williams, said recent tests ordered by the state showed just 10% of the water draining into the quarry was coming from the creek, the rest from underground springs.

“A lot of water is going in the sinkholes, a small amount is coming back to our quarry,” Williams told the news site.

Even if the 10% figure is accurate, Baylog said, it’s still enough to empty the creek when the pumps stop.

There’s more at stake than just a healthy trout-fishing stream, he added. The sinkholes are also a danger. The most recent one he saw had dug several feet into the bank, not visible to anyone standing among the trees above it.

“That could cave in at any time,” he said. “There’s a lot of parks around these creeks.”

Some homes on Bushkill Creek affected by sinkholes are empty, purchased by Hercules Cement, Nugent said, “after it became apparent that state and local authorities were not in a position to offer assistance." An entire bridge and road by the confluence of the two creeks have long been closed, also affected by the sinkholes. A bigger problem is the Route 33 bridge, a busy state road through the Lehigh Valley. According to PennDot, the bridge’s northbound and southbound lanes will be rebuilt in coming years, at a cost of up to $23.5 million, after “significant sinkhole activity” resulted in movement of the bridge’s pilings.

Sinkholes have plagued the bridge for more than two decades. Asked if any of the problems could be attributed to the cement plant, a PennDot spokesperson said in an email: “The area surrounding the bridges is in a very dynamic geological location.”

Baylog thinks the bridge’s problems are no coincidence.

“About 20 years ago, [Buzzi Unicem] did a major depth adjustment and dug quite a bit deeper. There was a lot more water going into the quarry and all these sinkholes started developing," he said. “It is getting worse.”

Pennsylvania’s DEP said the Hercules plant’s mining permit dates to 1974 and does not have an expiration date. The plant has a separate water discharge permit in the renewal process. The DEP said the plant’s most recent pump outage was not a permit violation.

A spokesperson for the Fish and Boat Commission did not return requests for comment about issues on the Bushkill. Baylog shared a September 2018 letter from the commission to the DEP’s mining office, in which it discussed three fish kills in 2017 and a dozen incidents prior to that due to “dewatering events as a result of period pump cessation."

Along with lightning strikes, Baylog said, another outage was caused by a squirrel in the motor.

Trout Unlimited wants Buzzi Unicem to invest in a permanent backup system that would ensure the water never stops flowing, according to Baylog. He said the company has mentioned alternatives, such as “lining” the creek with concrete in certain sections, which he believes would resemble the Los Angeles River in California.

His main concern: What happens if the plant, which employs 130 people, ever closes down. Would the quarry be left to drain the surrounding creeks dry?

Nugent said in a statement that the company has helped fill in sinkholes on adjacent properties. As for the pumps, Buzzi Unicem is evaluating potential solutions in development by hydrologic experts, “even though we are not obligated to do so.” The company, Nugent said, would share those solutions in the “near future.”

“There’s always a reason why it happens,” Baylog said. “We just want them to come up with a solution so that it stops happening.”