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Are those lagoons with the pretty views really doing their jobs?

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They may be nice to look at, but the myriad lagoons that dot area neighborhoods and gated communities are supposed to serve another function: keeping dirt and runoff from roads and construction sites from seeping into rivers and streams.

Biologists and ecologists, however, are re-examining how lagoons work and are finding that they don't necessarily keep other undesirable substances out of waterways.

That has prompted Beaufort County staffers to test local lagoons to see if they are doing their jobs.

"The problem is that they're designed for the removal of ... these sediments, but pollutants and some of the fecal bacteria from dog manure or leaky septic tanks can stay in the water," said University of North Carolina ecology professor Mike Mallin.

And in coastal regions, stormwater collected in small lagoons can easily overflow, sending pollutants like fecal coliform and phosphorous into nearby rivers.

Lagoons "like these are a very popular practice in flat coastal areas," said Tom Scheuler, a stormwater expert with the Center for Watershed Protection, a nonprofit organization that advises local governments on the best way to protect waterways.

"Developers love them, because everything they scoop out ... they can use for fill. And in golf course communities, they are considered an amenity, which everyone loves."

Beaufort County engineer Bob Klink said research on lagoons has been largely done in the northeastern U.S., and those results might not apply in the county. He explained that South Carolina gets more sunlight than northern areas, and sunlight kills fecal bacteria.

Professor Mallin agreed that sunshine can play a role in keeping pollutants out of area waterways. But it's unclear whether there's enough sunlight in the county to keep phosphorous and fecal coliform out of rivers and creeks, he said.

Klink recently asked the property owners association of Eagle's Pointe for permission to test its lagoon system, which he said is well-built.

The testing will involve comparing water entering a lagoon with the water leaving it. The process could take at least a year, Klink said, as the county plans to look at both well-designed and poorly designed lagoons.

Dan Ahern, county stormwater utility manager, said, "We've hung our hat on this system, so there's a bit of nervousness over the results."

Ahern said the county doesn't record how many lagoons exist in the county, but indicated it was a large number.

If the county's research shows the lagoons aren't keeping pollutants out of area waterways, Ahern said, a major overhaul would be in order.

The town of Bluffton also has questioned the effectiveness of lagoons, leading the Town Council to approve a stormwater ordinance in June that's been described as the most stringent in the state.

Some estimates indicate the ponds only filter up to 80 percent of pollutants before runoff is released into waterways.

Bluffton's law requires a major shift in how engineers and developers approach new projects. Among other mandates, it calls for a series of erosion controls in most projects, in addition to retention ponds to filter out pollutants. Those controls can include vegetation, pervious surfaces and wetlands.

The town has been trying to get the county to pass a version of its stormwater ordinance.

Island Packet reporter Daniel Brownstein contributed to this report.

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