Recently, the Norfolk District of the U.S. Army Corps of Engineers reported some interesting results from a study of the Rappahannock River. According to the Corps, Dr. Nathaniel Hitt, a research fish biologist with the U.S. Geological Survey, found in a multi-year study that there had been a significant resurgence in the American eel population in the river as far as 93 miles upstream from the former Embrey Dam in Fredericksburg, Virginia.

Benefiting Upstream Migration

The Embrey Dam was removed eight years ago. According to Dr. Hitt, "We've known that dams can have significant consequences for movement of shad and striped bass in large rivers, but what we learned in this study is that the effects can reach up into the smallest mountain streams." He noted that the changes in upstream migration were clear within two years of the dam's removal.

Dr. Hitt's findings are not unique. Here in Danville, Virginia, where I am based, the city removed the Brantley Dam along the Dan River last year. The city was concerned about the safety of the many boaters, kayakers, and swimmers who use the river for recreational purposes, but the dam's removal has proven beneficial to the environment as well. With the restoration of more than 7,000 feet of the river back to its natural banks, striped bass are migrating further upriver, and the ecosystems along this stretch, as well as the Fall Creek tributary, are now being replenished.

Restoring Our Rivers

With more than 75,000 dams greater than six feet in the United States today, it's important to focus on the maintenance and viability of this form of infrastructure in terms of both safety and the environment. Rivers connect upstream and downstream ecosystems, and dams can have a significant impact by reducing river levels; blocking and reducing flow; changing water temperatures; decreasing oxygen; and allowing silt, debris, and nutrients to accumulate. All of these results can be damaging to riverine ecosystems, including native fish, mussels, and other aquatic species.

Left in place, dams must be carefully maintained, whether still in operation or not. It's time to give serious consideration to the usefulness of our dams, and the benefits of their removal—including the restoration of the natural hydrology of our rivers and the return of native river species. For more information, visit the U.S. Fish and Wildlife Service and American Rivers.