DNREC’s decision to let more than a million gallons of sewage into the Mispillion River could come back to haunt it.

DNREC’s decision to let more than a million gallons of sewage into the Mispillion River could come back to haunt it.

“The Environmental Protection Agency is doing a full-fledged investigation,” Milford City Arborist Bill Pike said.

On Dec. 3, a broken sewer main under Route 1 forced DNREC to pump sewage into the Mispillion in order to relieve pressure on the pipe. By the time the system was back up, 1.6 million gallons of raw sewage had pumped into the Mispillion.

It’s not pleasant to think about – or smell – but, according to Pike, there could be more serious consequences later. That’s why he brought the situation to the EPA for an investigation.

“The Mispillion is one of the most pristine rivers in Delaware,” Pike said. “We need to look hard at this.”

EPA representatives said the department does not comment on ongoing investigations. DNREC representatives could not be reached for comment.

Pike said the river has already dodged one bullet, because the sewage was dumped during a cold snap. In warm weather, the nitrates in the sewage would have made a perfect breeding ground for algae. In turn, the algae would have suffocated fish by sucking oxygen out of the water.

“There would have been a major fish kill,” Pike said.

Instead of dumping waste into the river, Pike claims the state should have used a trucking service to ferry sewage from the pipe to a safe dumping ground. DNREC did use trucks for a short while, but it didn’t last.

“Just get them lined up like a convoy, one after the other,” he said. “They had 24 hours to plan it.”

But a fish kill might have just been delayed. While the liquid waste was eventually swept out of the river, solid waste most likely sank to the bottom, Pike said. Unless something happens to stir up the riverbed, it will stay there until it decays, breaks up and dissolves into the water.

And if that takes until spring or summer, it could lead to the same kind of algae bloom the cold weather stopped earlier this month.

“Hopefully there won’t be an algae bloom, because this stuff will break down before that,” Pike said. “But we can’t be sure. If it happens, there’s really nothing you can do but let it run its course.”

A heavy rainfall during the bloom would replenish the water and help keep more fish alive, but that is a matter of luck, he added.

Nobody has found a way to break up the waste safely. Dredging the riverbed would be expensive and incredibly disruptive to its ecology, and there are no chemicals that could do the job without causing more harm than they’d prevent. 

“The only good thing about it is that it’s a natural, biodegradable material,” Pike said. “It will go away eventually.”

There could be consequences in other waterways, too. A smaller amount load of sewage – 50,000 to 60,000 gallons – was pumped into Swan Creek near Tub Mill Pond. That could lead to the same problems the Mispillion is facing down the line.

“There’s not enough flow coming out of Tub Mill Pond even in a heavy rain to flush all that out,” Pike said. “My opinion is that it’s going to sit in the upper reaches of Swan Creek for months.”

Whatever happens, Pike said, he’s going to keep pushing for a thorough investigation.

“I’m going to keep on top of it. I told them I’m not going away,” he said.