Each fall for nearly a decade, volunteers have set out across Hampton Roads to help pinpoint where floodwaters creep and what’s in the water.
A coalition led by the Norfolk nonprofit Wetlands Watch launched the annual “Catch the King” event in 2017 to learn more about the region’s true scale of tidal flooding.
The name refers to the especially high king tide, which happens when the moon and sun align with Earth.
Last October, 187 volunteers participated across Hampton Roads, including the seven cities as well as the Eastern Shore, Historic Triangle and up to the Northern Neck.
Using a locally developed phone app called Sea Level Rise, the citizen scientists including local students and Girl Scout troops record GPS locations and depths of flooding.
It was a bad year for flooding, but good for data collection. Norfolk saw an “unprecedented 19-day stretch of high water” from mid-September to mid-October, said Gabi Kinney with Wetlands Watch.
Average water levels peaked at around 5 feet, more than a foot higher than what was predicted.
The group collectively marked nearly 23,000 data points, Derek Loftis, an assistant professor at the Virginia Institute of Marine Science, said at a Catch the King celebration this week.
Here’s some of what local scientists and environmental leaders learned.
Flooding in Hampton Roads often goes beyond what scientists predict.
Loftis said VIMS found several spots in the Catch the King data where GPS markers denote flooding that doesn’t match its computer modeling.
“They give us some context into exactly how much inundation happens in each of these places,” he said. “We can see what was the predicted maximum by the model versus what was actually observed by individuals.”
He said one of the biggest unanticipated benefits of Catch the King was free ground-truthing of what was missing from aerial surveys that use a laser system called lidar.
That has allowed scientists to correct some technical discrepancies that would usually require expensive field surveys, Loftis said.
“The beauty of this is that we’re not only collecting new data and new places that we hadn't previously mapped before, but we're also consistently still mapping a lot of the same places every single year that are giving us enough information to produce these new data-driven models.”
That way, he said, “we’re not waiting for a catastrophic hurricane” to find out where there are issues.
With each passing year, Hampton Roads is expected to see more days with tidal flooding because of rising sea levels driven by climate change.
The water is yucky. Don’t wade in it.
During Catch the King, Old Dominion University professor Margie Mulholland leads a companion effort called Measure the Muck.
A subset of volunteers, including some of her graduate students, go out to flooding sites equipped with coolers, gloves and small bottles to gather water samples.
The team collected hundreds of samples last fall, primarily from the Lafayette and Elizabeth rivers, but also in Poquoson and Gloucester.
More than 80% were found to have harmful bacteria “not safe to be in contact with” under Virginia regulations, Mulholland said. Past years have come back even higher, with over 90% of samples considered unsafe.
The alarming contaminant is Enterococcus bacteria, which often comes from fecal matter and can cause a range of infections for people who come into contact with it.
Mulholland said she knows someone’s child who wound up in the hospital with an infection after playing in floodwaters with an open cut on their leg.
This was the first year her team also tested the water for a group of man-made chemicals called PFAS, or “forever chemicals.”
She said they’re waiting for lab analysis for a breakdown of the data – but they know the water contained some levels of PFAS.
A rising threat to the Chesapeake Bay
The original inspiration behind Measure the Muck was to assess nutrient pollution in floodwater.
Nutrients like nitrogen and phosphorus are a key driver of the Chesapeake Bay’s water pollution, which can lead to blooms of harmful algae and deprive marine life of oxygen.
Mulholland said around Norfolk, she’s seen trash cans spilling into tidal waters on residential streets and flooding covering dog parks.
All that waste then gets swept off land into local waterways that feed into the Chesapeake.
“The water rises and sits there a while, and then it gets carried back when the tide goes out,” Mulholland said.
The U.S. Environmental Protection Agency sets a “pollution diet” associated with the massive, multi-state Chesapeake Bay restoration, limiting the amount of nutrients that can enter the water from sources such as farms and wastewater treatment plants.
Mulholland said the effects of tidal flooding aren’t counted toward that load. That could have ramifications for the ongoing restoration, especially as high tides keep growing.
Her students are also studying land use surrounding high tide hotspots to find the sources of pollution and how they differ between urban and rural environments.
Wetlands Watch hosted a Catch the King art competition this year, asking local high school and college students to submit artwork or writings inspired by rising waters on the Virginia coast. Members of the public can soon vote on their favorite at wetlandswatch.org/catchtheking.
