NEPTUNE, N.J. -- The cloud of fecal bacteria that lingered off New Jersey beaches last week is a reminder of a grim truth on the Shore: The water is not safe after it rains.
The reason why is pretty easy to understand, but the solutions are harder to envision here in the most developed U.S. state, where one out of every eight square feet of land cannot be penetrated by water because of a manmade structure.
Shopping malls, restaurants, parking lots and roofs of every shape and size prevent rainwater from soaking into the soil and naturally filtering down into the water table.
Instead, for every inch of rain that falls on a typical neighborhood, tens of thousands of gallons of rain are funneled through the streets and sewers.
It's on this journey where the rain absorbs bacteria from bird, dog and (occasionally) human waste before the now-tainted rain is discharged out into nearby streams and rivers, which then feed all of that pollution into the bays and ocean.
The Shore needs to restore some semblance of the natural order, in which water soaks into the ground where it lands rather than being funneled elsewhere, experts say.
"That's tough, tough, tough to do when the area is already urbanized," said Susan Libes, director of the Environmental Quality Lab at Coastal Carolina University in Conway, South Carolina.
The big question: Is it safe for you and your kids to splash around in the ocean on a sunny Saturday after a downpour the previous night?
The Asbury Park Press took that query to the head of the New Jersey Department of Environmental Protection's coastal water watchdog.
Bacteria levels on most Shore beaches after a storm are not truly dangerous, even if they are above the safe-swimming standard, said Bruce Friedman, director of the state DEP's Division of Water Monitoring and Standards.
Local officials always have the power to shut down their beaches for public health reasons, he added.
Still, Friedman said he'd wait a while before wading.
"I wouldn't be concerned 24 hours after a rain event to swim at the beaches in New Jersey," said Bruce Friedman, director of the state DEP's Division of Water Monitoring and Standards.
On Tuesday, the state announced 47 Jersey Shore beaches were under bacteria advisories after testing on Monday revealed an excessive amount of enterococcus, a bacteria that grows alongside feces in the guts of warm-blooded animals, including mammals, birds and humans.
When its numbers climb high enough, enterococcus is considered a red flag that dangerous pathogens are also present in the water.
Nearly all of those beaches were cleared for swimmers by Wednesday afternoon, but the worst day for Shore beaches in at least 13 years revived memories from the 1970s and 1980s, before environmental regulations cleaned up our waters.
This doesn't just happen in New Jersey. Most any seaside town in Texas, Florida, Hawaii, New York, California and elsewhere all have similar issues - practically all are even worse than what the Shore deals with, according to available U.S. EPA data.
"There is a web app here that you can use to get a prediction of what the bacteria levels are going to be and it's largely based on the rain forecast," said Libes, of Coastal Carolina University. "So we understand pretty well that this storm runoff is a pretty big player."
As a general rule, Forrest Bell, a scientist who runs an environmental consultancy that specializes in stormwater management in New England, says you should avoid beaches near the mouths of rivers, streams and any other conduit that transports urban stormwater.
"I would not allow my children to swim or play in those waters as there is certainly a much higher risk of contact with pathogens," Bell told the Press. "However, there are often areas at a beach that have much lower counts and are safer to swim at than other areas."
"Impervious surface" is a term in hydrological lingo for things like roads, parking lots, driveways, sidewalks and roofs.
Experts say that when impervious surfaces make up 8 percent or more of the total landscape, waterways are at greater risk of degradation.
New Jersey, as a whole, reached that threshold in 2011, according to the National Land Cover Database. No other state has a higher share.
The most recent statewide figure is somewhere north of 12 percent, according to a 2016 analysis by the Rutgers Cooperative Extension Water Resources Program.
The program looked at a few coastal towns in Monmouth County in 2016. The results weren't pretty.
Even parts of western Monmouth County, which is less densely populated than the coastal communities, is far more waterproof than it should be.
Lowering the share of land that is impermeable is the answer to the problem, but it's not practical to expect developers to replace relatively new parking lots with something more friendly to stormwater, according to Chris Obropta, head of Rutgers Water Resources Program.
"As people redevelop or fix developments, you can ask them to do just a little bit more, do their share," he said in a 2016 community meeting.
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Why fecal bacteria sometimes takes over Jersey Shore beaches