DNREC to conduct water-quality dye test to evaluate oyster beds

DOVER – The Department of Natural Resources and Environmental Control’s Delaware Shellfish Program and Kent County Levy Court will conduct a week-long water quality study starting June 10 in the Murderkill River and Delaware Bay to evaluate the bay’s oyster beds. The study calls for applications of the red dye Rhodamine WT, which is commonly used in water quality and dispersion tests, and is not considered harmful to the public or the environment.

Weather permitting, application of the dye will be made at the Kent County Waste Water Treatment Plant near Frederica into a tributary of the Murderkill River to measure water flow and dispersion in waters where shellfish are harvested, according to DNREC’s Delaware Shellfish Program within the Division of Watershed Stewardship.

DNREC’s shellfish program utilizes a classification system that regulates the harvest of shellfish based on water quality, and which also assesses the potential risk to shellfish harvesting in the event of a wastewater spill. The goal of the red dye study is to help determine the potential impact to oyster beds in the possible event of a wastewater spill or other pollution event.

Dye applications are planned near late-evening low tide on Tuesday, June 11 and will continue until around noon the next day. As a result of the dye applications, portions of the Delaware Bay, Murderkill River and St. Jones River may turn reddish in color. The extent of water discoloration could be fairly widespread but should disperse within 48 hours.

The study – known as hydrographic dye dilution – will be conducted by DNREC in conjunction with the U.S. Food and Drug Administration (FDA) and Kent County Department of Public Works. Results will help to 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. Information collected will be used by the FDA and DNREC to evaluate potential water quality impacts and closure of shellfish growing areas in the Delaware Bay under such emergency situations.

For more information on DNREC’s Delaware Shellfish Program, please visit de.gov/shellfish.