PROBLEM: Historically, anadromous fish species (e.g., herring, shad, and striped bass) have migrated en masse from the Atlantic Ocean and Chesapeake Bay into the freshwater non-tidal Anacostia tributaries to spawn. During the past four decades, their annual upstream migrations have been largely prevented by over two dozen unintentional and man-made barriers located primarily along the lower portions of tributaries such as the Northwest and Northeast Branches, Paint Branch, Indian Creek, Lower Beaverdam Creek, Sligo Creek and Watts Branch (Figure 28).

STRATEGY: Remove or modify key fish barriers to expand the available spawning range for anadromous fish, and improve the quality of their spawning habitat. Once expanded, selectively assist the anadromous fish communities to genetically Aimprint@ on their newly opened territory to encourage the return of future generations.

PROGRESS:

Fish Barrier Removal/Modification
Since the early 1970s, more than 25 major Anacostia fish blockages have been identified by the Maryland Department of Natural Resources, Interstate Commission on the Potomac River Basin and others. Recognizing fish barriers as a major state-wide problem, the Maryland Department of Natural Resources in 1987 made a major commitment to improve fish passage throughout the Chesapeake Bay Area, including the Anacostia. From 1989 to 1990, this initiative gained local momentum through the formation of the ad hoc Anacostia Anadromous Fish Workgroup. Led by the Interstate Commission on the Potomac River Basin (ICPRB), the workgroup (which comprised local, state, Federal and regional agency representatives) both established Anacostia fish blockage removal/modification priorities and helped strengthen overall coordination and support for this effort.

From 1990 to 1991, the ICPRB drop-in-the-bucket brigade manned by students from Paint Branch, Blair and Parkdale High Schools and Eastern Intermediate School captured and transported hundreds of alewife herring over the Northeast Branch weir. This fish reintroduction effort was done with the goal of chemically imprinting larval herring in the stream so that they might return years later as adults and proceed upstream of current barriers. Follow-up electrofishing monitoring of upstream areas suggest that this effort has had a positive effect.

In 1991, the Maryland-National Capital Park and Planning Commission working in partnership with a private developer, modified the Northeast Branch grade control weir located at River Road, greatly expanding the anadromous fish spawning range in this tributary system. This modification effort, which also included the creation of a large boulder field area for aiding anadromous fish passage and enhancing resident fish habitat, has been a major success for both fish and angler alike (Figures 29 and 30).

Figure 29. Northeast Branch Weir Fish Barrier Modification Work, 1991.

Figure 30. Local Anglers Fishing Below Northeast Branch Weir at River Road, 1996.

The Maryland State Highway Administration, in 1994, installed both a concrete step pool structure and Denil fish ladder along Paint Branch within the Capital Beltway (I-495) Inner and Outer Loop culverts. These structures have potentially opened up an additional two miles of stream to river herring (i.e., blueback and alewife herring).

As part of its $800,000 Section 1135 Anacostia Floodway Rehabilitation Project, the U.S. Army Corps of Engineers, in 1995, completed the following anadromous fish barrier-related projects:

Figure 32. ICPRB Fisheries Biologist Measuring Alewife Herring Caught in Northwest Branch

During the period from 1990 to 1997, the Interstate Commission on the Potomac River Basin continued its on-going efforts to document and evaluate the range, strength and diversity of anadromous fish runs in major Anacostia tributaries such as the Northeast and Northwest Branches (Figure 32)

Figure 33. Increase in Available Anacostia Tributary Herring Spawning Habitat, 1991-1997 (COG, 1998).

As seen in Figure 33, between 1991 and 1997, a total of approximately 18.2 miles of potential herring spawning habitat was recaptured in the Anacostia watershed. The greatest gains were recorded in the Northeast Branch tributaries such as Paint Branch, Little Paint Branch, Indian Creek and Beaverdam Creek (which were major beneficiaries from the modification of the Northeast Branch weir structure at River Road).