The Maryland Department of the Environment is proposing to change the stream designation of the North Branch Potomac River near Westernport extending to Dawson from a “Warm Water Aquatic Life” use to Maryland’s “Cold Water Aquatic Life and Recreational Trout Stocking” uses.  

Under federal regulations (40 CFR § 131.10), water quality standards must protect "existing uses," which are uses the waterway has attained on or after November 28, 1975. Maryland’s antidegradation policy (COMAR 26.08.02.04-1) aligns with federal regulations by requiring that any existing use—a use that a waterbody currently supports, even if it is not formally reflected in its designated use—must be protected. If the current designated use does not fully protect the existing use, the state must act to safeguard the higher-level use and its supporting water quality.

A hybrid public hearing will be held for the North Branch Potomac River (Allegany County) existing use determination and rationale document on December 2, 2024 from 5:30 p.m. to 7:30 p.m. to hear comments from the public regarding the proposed existing use determination and rationale document.  

This hearing provides an opportunity for community members, environmental groups, industry representatives, and other stakeholders to share their perspectives and submit feedback on the proposed re-designation. 

For in-person attendees, the meeting will be held at: 

Westernport Library
66 Main Street
Westernport, MD 21562 

Warm Water vs. Cold Water Streams in Maryland

Warm water and cold water streams in Maryland support different types of fish and aquatic life. Warm water streams are suitable for warm water fish, while Maryland’s cold water streams support species like trout and cold-water benthic macroinvertebrates (aquatic insects). Trout and cold-water benthic macroinvertebrates are sensitive to higher temperatures, so cold water streams have stricter temperature limits (maximum 68°F or 75°F) compared to warm water streams (maximum 90°F).

Historical and Recent Changes in the North Branch Potomac River

The North Branch Potomac River has experienced significant changes in recent decades. For over 130 years, it received heated wastewater from the Luke Paper Mill, a paper production facility in Westernport, Maryland, which employed 675 people. The mill raised the river’s temperature, but upstream reservoirs helped maintain the conditions that allowed the Maryland Department of Natural Resources (DNR) to successfully manage trout populations there since 1989.

Since 2015, sections of the river have consistently met the 75℉ temperature requirements for a Class IV - recreational trout water. After the mill closed in 2019, the river's temperature dropped further. Monitoring now shows that the river not only meets the trout stocking standards further downstream in Dawson, but also satisfies the stricter limits (68℉) for supporting natural cold water aquatic life in certain areas. Biological surveys since 2019 show an increase in trout populations and, in 2023, DNR discovered cold water benthic macroinvertebrates—key indicators of healthy cold water conditions.

The Proposed Re-Designation

The proposed re-designation reflects the observed ecological improvements and ensures long-term protection for the cold water fish and benthic communities that now thrive in segments of the North Branch Potomac River. This action also safeguards the river’s value as a recreational trout fishery, benefitting local anglers and fishing guides, and the regional economy. 

As climate change causes stream temperatures to rise, cold water habitats like those in the North Branch Potomac River are becoming increasingly rare. Protecting these habitats is essential for species like trout, which are highly sensitive to warming. The proposed action preserves the river's unique cold water environment while balancing the region's economic needs, ensuring the river remains a valuable resource for wildlife and recreational fishing.

Impacts on National Pollutant Discharge Elimination System (NPDES) Permits

For facilities that currently hold NPDES permits for discharge into the affected waters, the thermal impact of those discharges will be evaluated at the time of the next permit renewal cycle to confirm that existing permit requirements are protective of the cold water existing use. Stream segments proposed for redesignation are meeting their cold water use even with the existing permitted discharges occurring.  

Any new permit application for discharges into applicable stream segments would also need to meet the temperature criteria associated with the proposed existing use designation. Permit requirements would be evaluated on a site-specific basis, incorporating data on the proposed discharge, ambient background flow and water quality conditions around the discharge point, and thermal mixing criteria described in the regulation. Technologies such as cooling towers, heat exchangers and chillers can help new facilities reduce the thermal impacts of their discharges to comply with stricter temperature standards. These solutions are adaptable for various operations and can protect cold water ecosystems like the North Branch Potomac River while supporting new discharges.​