Wetlands can be a real pain in the butt if you’re a developer trying to build something in them. They must be ditched and pumped dry and topped with tons of dirt. Despite your best efforts they get soggy again come the first good rain.
The developers of the Dollar Tree and Verizon stores on N.C. 24 here in Swansboro are finding out just how stubborn wetlands can be. They chose a site that is about half wetland. They’ve been pumping them for weeks, dumping the water in a storm ditch along Main Street Extension. When they started clearing the site and disturbing the soil a few weeks ago, the discharge turned the color of chocolate milk, which seemed to violate the state’s turbidity standards. Those rules prohibit visible off-site sediment from any land-disturbing activity.
That water ran through the ditch, went under the road, through the Ace Hardware property, then under N.C. 24 and eventually into Halls Creek. The creek is designated by the state as a shellfish-growing water body. It’s already considered polluted by stormwater runoff.
Sedimentation is one of the leading causes of water pollution. It leads to fish kills, clogged streams, reduced storage volume of reservoirs and added filtration costs for our municipal water supplies. The smaller soil particles remain suspended in the water. These suspended particles block out light filtering through the water, reducing photosynthesis and altering the ecology of our streams.
I took some pictures and a couple of samples of the water coming out of the discharge pipe and sent them to Holley Snider, an inspector with the N.C. Division of Energy, Minerals and Land Resources. The division enforces the sediment standards. Snider told me that the pictures seemed to indicate a problem. She spoke with the developer, Chris Bailey of Jacksonville, and visited the site on a day when no pumping was going on. She suggested that Bailey place a big nylon bag at the end of the pipe to filter sediment out of the discharge.
Bailey complied. But I had my doubts. These silt bags don’t do a very good job at capturing the finer sediments. After a heavy downpour early yesterday morning, my fears were confirmed. Black water poured from the bloated sediment bag and down the ditch along Main Street extension.
This time I brought a turbidity tube with me. Turbidity is a measure of the cloudiness of water. The higher the turbidity, the harder it is to see through the water. Turbidity measurements are reported in nephelometric turbidity units (NTU) or Jackson turbidity units (JTU). Different units are used depending on which method is chosen to measure turbidity. The two units are roughly equivalent and can be used interchangeably for field purposes.
With the naked eye, an average person can begin to see turbidity levels starting at around 5 NTU and greater. Lakes that are considered relatively clear in the United States can have a turbidity up to 25 NTU. If water appears muddy, its turbidity has reached at least 100 NTU. At 2,000 NTU, water is completely opaque. Water bodies in North Carolina with NTU of more than 50 are in violation of water quality standards.
Keep those numbers in mind.
The clear plastic tube is about two inches in diameter and about four feet tall. At the bottom is a black and white disk. You pour your sample into the tube until you can no longer see the disk from the top of the tube. A scale on the side gives you the NTU measurement.
I poured less than a half inch of the water coming out of the silt bag into the tube and the disk disappeared. That corresponded to NTU greater than 250, the limit of the tube’s measurements.
I also measured the runoff in a side ditch not affected by the discharge. It had a NTU of 30. Where the two streams met, the difference was stark.
I took more pictures and sent them to Snider. I suggested that pumping the wetlands be stopped until a way is found to keep mud out of our creeks. She sent my photos on to Bailey and to Gary Pope of Johnson Grading who is doing the site work along with this email:
“Gary, per our phone conversation, please provide me with an update of the conditions of the site in response to this email, a copy of the required report from last night’s rainfall event and any additional measures being taken to reduce/limit turbid water from leaving the site. It may be necessary to cease and desist pumping water, including water thru the silt bag, if the water that is leaving the site would result in a violation of the State’s water quality standards.”
The pumping stopped Monday afternoon.
We in Swansboro passed a tough watershed plan last year that commits the town to reducing the flow of polluted stormwater runoff into our surrounding waters. We instituted an annual stormwater utility fee a couple of years ago. Every property owner in town now contributes to help fund ways to reduce flooding and the flow of water pollution.
Everyone must do their part, including those who choose to build in our town. They should know that someone is watching.