Marshyhope Creek is a key tributary of the Nanticoke River and largely responsible for its characterization as one of the cleanest and healthiest rivers on Chesapeake Bay. It has extensive forested wetlands and Maryland’s only known reproducing population of Atlantic sturgeon.
The Maryland Department of the Environment (MDE) has issued a tentative discharge permit to AquaCon for an extremely large salmon Recirculating Aquaculture System (RAS) facility to be located at the portion of the Marshyhope where these sturgeon are known to spawn. The facility would discharge 2.3 million gallons per day of “purge” water into this small tributary.
MDE’s analysis has not adequately gauged the significant risk posed by this massive facility to the sensitive ecosystem of the Marshyhope.
MDE examined two similar facilities’ applications in Maine and determined the current project would have an acceptable effect on the receiving waters. However, the agency did not conduct a hydrodynamic assessment or any in-state environmental impact study.
MDE concluded, “The most notable difference between these two operations and the one proposed in Maryland is that the Maine RAS systems have much larger discharge volumes.”
This is a misleading and dangerous comparison. It fails to consider the huge difference in receiving water volume of tiny Marshyhope Creek compared with the much larger Penobscot Bay. The ratio of discharge volume to receiving water volume for the Maine systems is about one percent, while using AquaCon’s estimate, this proposed project would have an impact on the Marshyhope that is eight times to 15 times greater.
Maryland has worked hard to limit adverse impacts of both impervious surface and urban runoff, but this plant would hardtop over 25 acres. Fresh water runs into Marshyhope Creek from the land. This land is the Marshyhope’s watershed. It receives water from rain, snow and irrigation. Some of this reaches the creek as surface runoff and some filters into the soil first, entering the creek as groundwater. Marshyhope’s watershed surrounds the creek and all its tributaries.
By using stream gauge measurements of the average flow of the creek, we can estimate the average input of fresh water that feeds into the Marshyhope from each square mile of its watershed. For the months of July through October, the period when Atlantic sturgeon are known to spawn, this amount ranges from about 0.4 to 0.58 million gallons per day per square mile. Thus, the contribution of the wastewater from the AquaCon plant would range from four to six square miles of watershed flows.
These estimates of proportion of daily flows and of square miles of watershed inputs represented by the AquaCon discharge volume are based on 20-year average flows. However, monthly average flow well below that commonly occurs. The proportional contribution could reach 20 percent or more, and the number of square miles of watershed flows could exceed 10 square miles. Yet even the conservative estimates would represent a substantial disruption of the existing flows and characteristics of the water in this very small tributary, posing a threat to the eggs and larvae of sturgeon and other fish species.
We are concerned that MDE has rushed into approving this project without considering commonly possible adverse conditions or events that would likely harm native fish species, especially the Atlantic sturgeon, which is listed federally and by the state as endangered. Our state’s agency for environmental protection should make addressing these threats a priority and encourage siting of this facility in a location that does not carry such an unacceptable risk.
Nick Carter, retired
Judith Stribling, Salisbury University faculty emerita