Murderkill River runs red for reason

As part of a “hydrographic dye dilution” study performed Wednesday, DNREC and its partner agencies dumped a blood-red dye called Rhodamine WT into the Murderkill River near Frederica for a 12-hour period to examine the river’s hydrology. (Submitted photo/DNREC)

FREDERICA — For a few days last week, a portion of the Murderkill River, near the Kent County Waste Water facility, ran red. But, despite the river’s grisly sounding name, the blood-red coloring was only a dye called Rhodamine WT.

In a joint effort initiated by Department of Natural Resources and Environmental Control’s (DNREC) Shellfish Program, Kent County Levy Court and the U.S. Food and Drug administration, researchers pumped the dye over a 12-hour period (from late Tuesday night until around noon on Wednesday) through the county’s treatment facility. Discharged from the facility’s effluent pipes (as ordinary treated wastewater would be), the dye was tracked and observed as it dispersed into the Murderkill River and eventually into the Delaware Bay.

DNREC environmental scientist Michael Bott says the study — known as a hydrographic dye dilution — may eventually provide data that can help the agency (and Kent County government) plan for disaster.

“The study looks at the hydrology in the Murderkill and the bay,” said Mr. Bott. “The dye simulates an emergency event like a catastrophic sewage spill. By looking at it this way, we can see how the flow goes through the river and examine what the potential impact to the shellfish — specifically oysters — would be. Eventually, we can use the information to update our emergency management plan, such as temporary suspensions of shellfish harvests.”

As the dye spread in the river, it was observed visually, but also through the use of a network of “flowometers” that could track concentrations that the naked eye would miss.

Interested in the results of the study, Kent County public works director Diana Golt thinks the data will provide valuable insights on the plant’s interaction with the river.

“Based on the modeled scenario, the results may show that the plant flows have limited impact on the oysters and the environment,” she said.

The dye used is a common agent employed in water quality and dispersion tests, and is not considered harmful to the public or the environment. Much of the dye tint has already dissipated, at least visually, noted Mr. Bott.

In the coming months, researchers will crunch the data, but Mr. Bott says the final analysis could take up to a year to generate. But, results may help appropriately classify shellfish harvesting waters, assess risk, and facilitate emergency closure provisions in the event of a wastewater spill associated with extreme weather or natural disasters, such as hurricanes, nor’easters, or heavy flooding.

For more information on DNREC’s Delaware Shellfish Program, visit

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