Why do beaches close after a storm? The issue dates back to the 1800s

A heat wave came through Connecticut after Tropical Storm Henri, but residents found public beaches closed to swimming.

It took days after the storm for all public beaches to open up again, as it does after every major storm.

The reason beaches close after major storms, and sometimes in anticipation of major storms, is a problem that goes back to the 1800s that is costing Connecticut billions to fix.

“All of our big cities have a combined sewer system,” said Mike Dietz, director of the Connecticut Institute of Water Resources at the University of Connecticut.

“There are discharge points where combined sewage and stormwater gets — raw sewage, now, not treated — gets discharged directly into our rivers or our estuaries,” said Mike Dietz,

As Dietz explained, most sewage systems in our state were built in the 1800s when mixing stormwater with sewage was the right thing to do.

“The stormwater was put in there on purpose, basically to help keep that system flushed out and keep it moving to keep it clean,” he said.

In New Haven, for example, some pipes in the system date back more than 150 years.

“Our earliest pipes were being put in the 1860s and 1870s,” said Gary Zrelak, director of operations for the Greater New Haven Water Pollution Control Authority.

Since then things have changed, according to Zrelak. Stormwater and sewage are separate systems, but in a big enough storm, there is overflow and all of it gets dumped into the Long Island Sound.

In New Haven, Zrelak explained that the area’s sewage treatment facilities can handle regular rainfall. A storm that drops 2 inches over 48 hours might be no problem. But during a storm like tropical storm Henri, there might be 2 inches of rain in four hours. That can cause a combined sewer overflow.

“The rainfall issue is really about intensity,” he said.

New Haven’s sewage treatment facility handles about 30 million gallons a day.

“We’ll go up to 100 million gallons a day during a rain event,” Zrelak said.

‘Effluence’

The question is the amount of toxins, specifically bacteria, that get dumped into local waterways from combined sewage overflow events. The amount of allowable toxins depends on the specific use of the waterway, said Traci Iott, a supervising environmental analyst at the state Department of Energy and Environmental Protection explained.

Beaches get closed, she said, when “there's data that indicates that the bacteria levels are higher than the criteria that we have, that are set to be safe for public health for swimming. So, if we have bacteria data, and it's higher than that, then we'll generally close the beach until we can go back and retest, and make sure everything's good.”

It can even happen before any testing for bacteria, as state Department of Health toxicologist Stewart Chute explained by email: “Rainfall amounts in excess of a threshold (generally two inches/24 hours) can also, under the authority of the local health director, also close a beach. This is an example of a ‘preemptive closure.’”

The state Department of Energy and Environmental Protection oversees state beaches in coordination with the state Department of Public Health. Municipal beaches are overseen by local municipalities, with the U.S. Environmental Protection Agency setting the levels of bacteria in the water considered acceptable.

Bacteria are measured by the number of “colony forming units” per 100 milliliters of water.

A state or municipal employee will take a sample of water and, if the levels exceed 235 cfu of fecal coliform bacteria per 100 milliliters of freshwater, or 104 cfu of enterococci bacteria per 100 milliliters of marine water, then the beach is closed to swimming.

Sewage overflow is not the only reason beaches get closed. There are at least six conditions that will force a beach closure, including regular rainfall.

Stormwater has to go somewhere.

“We're talking about the roads, parking lots, driveways, rooftops, everything that basically water cannot pass through, water sheds off of those surfaces, and is most of the time directed into a stormwater system, a separate stormwater system, where it goes directly into the local waterway untreated,” Dietz said.

Iott said it depends on how far a source of contamination, say a large concentration of bird excrement, is from a water source.

“We've got a lot of hard surfaces in Connecticut,” she said “So, when you have rain that falls on a hard surface, then whatever it picks up, it's got a straight line to a water body.”

When asked if we are ever swimming in clean water, Dietz explained that it was more complicated than a yes or no question. He said there are naturally occurring toxins that would get flushed into the Sound even if there were no people at all.

“Clean is a relative term,” he said. “These natural waters are never going to be free of bacteria. Bacteria is a naturally occurring thing in any water.”

Billion-dollar projects

Managing water, both sewage and rainfall from larger and smaller storms, has been an ongoing issue for decades.

“When they first started this in the 80s, they started separating pipes,” Zrelak said. “When we started getting into the 90s, people started shying away from that.”

Other projects have attempted to build storage tanks to hold excess water from combined sewage overflow events until it can be safely handled.

“We’ve tried some of that, but it gets very expensive,” Zrelak said.

Water mitigation plans are not single projects but layered, involving separating pipes, upgrading sewage treatment facilities, pump stations and other pieces of infrastructure.

Greater New Haven’s plan, the “Bible,” as Zrelak called it, calls for $400 million to be spent over 15 years, and there are similar projects in many Connecticut cities.