Dam breaching clears way for fish; Project will open spawning grounds near Potomac River structure


GLEN ECHO -- Little Falls Dam on the Potomac River, built to help supply metropolitan Washington with drinking water, has kept American shad from reaching its prime spawning waters for 40 years.

Yesterday, state and federal officials knocked a hole in the dam, ceremonially speaking.

Bruce Babbitt, U.S. secretary of the interior, joined Gov. Parris N. Glendening, Democratic Sen. Paul S. Sarbanes, Republican Rep. Constance A. Morella and others to celebrate the beginning of work on a notch in the dam that will allow shad, striped bass, sturgeon and perch to reach their historic spawning grounds in the 10-mile stretch north of the dam.

Work on the 1,400-foot dam, upstream from the District of Columbia, marks another step in a national campaign to remove obsolete dams that stand in the way of fish that live most of their lives in salt water but migrate up freshwater rivers to reproduce.

Since Colonial days, Americans have built about 75,000 dams to harness the power of water and to provide drinking water.

But those dams have killed fish migrating upstream to spawn, decimating shad and other populations. Recently, many of those dams have been torn down or breached.

Babbitt has crisscrossed the country for seven years to be part of dam-breaching ceremonies. He was in Maine in July when the Edwards Dam came down. It had been blocking the Kennebec River since Andrew Jackson was president.

Yesterday, he said breaching the Little Falls Dam should be used as a start to "use our resources to restore this entire river basin."

Opening a way for spawning fish to get past the dam is a priority in Maryland's fish passage program, which is part of the 1987 agreement to restore the health of the Chesapeake Bay. In a report on the health of the bay released last month, the Chesapeake Bay Foundation rated rockfish at 75 on a scale of 100, rating shad at three.

The fish passage program, which has reopened nearly 300 miles of rivers in Maryland, should help the shad ranking, state officials say.

The dam, which supplies about 20 percent of the Washington area's drinking water, was built in 1959 with a fish passage at Snake Island, a half-mile-long stretch of brush and trees in the middle of the river.

But the fish passage never worked because it was too far downstream, too far from the Virginia side where fish congregate, and was frequently clogged with debris that washes down the river during spring floods. It was closed in 1964.

The shad fishery in the Potomac plummeted, from an average of 300,000 landings a year in the 1950s to a population now estimated at 10,000 fish.

Maryland imposed severe restrictions on shad fishing in the river in 1982.

Plans to breach the dam were stalled until Mufeed Odeh, a bioengineer for the U.S. Geological Survey, devised a series of "weirs," elongated "W's," placed at intervals across the 25-foot opening.

The weirs provide the depth of water that the fish need and slow the flow enough to enable them to swim against it.

The notch in the dam is being built 75 feet from the Virginia side. Cranes are in place, and crews are building a small temporary barrier to divert water from their work area, said Col. Bruce Berwick, Baltimore district engineer for the U.S. Corps of Engineers.

Soon, they will use jackhammers to blast away the concrete, then move the weirs into place. Work should be finished by late March, in time for the beginning of the shad run.

Pub Date: 10/13/99

Copyright © 2021, The Baltimore Sun, a Baltimore Sun Media Group publication | Place an Ad