USACE Sets the Rappahannock River Free

Abstract : The US Army Corps of Engineers (USACE), usually known for designing and constructing water control structures, has taken on a very different engineering challenge bringing down a 150-year-old dam. On 23 February 2004, the Norfolk District of USACE began this historic mission. Six hundred pounds of explosives set by the Army and Air Force Reserves blasted a 130-foot section in the middle of Embrey Dam in Fredericksburg, Virginia, allowing the Rappahannock River to flow freely for the first time in more than 150 years. The detonation opened approximately ten 10-foot holes in the structure, allowing fish to pass through as part of their natural migration cycle. The Rappahannock River flows 184 miles from a spring in the Blue Ridge Mountains to the waters of the Chesapeake Bay. Fredericksburg, a historic Virginia town founded in 1728, sits at the fall line of the Rappahannock. A wooden crib dam was the first dam built on the falls in 1853. In 1910, the Fredericksburg Water Power Company finished construction on a 770-foot-long 22-foot-high concrete dam that spanned the Rappahannock River. The Embrey Dam was an Ambursen-type dam, consisting of a series of reinforced concrete buttresses (14 feet on center) with sloped (38 degree) concrete slabs on the upriver side. It was used to generate hydroelectric power until the 1960s. The city of Fredericksburg also used water diverted by the dam into the Rappahannock Canal as a raw water source for the city s supply until early 2000. In 1985, a group of Fredericksburg business owners, politicians, and community members formed Friends of the Rappahannock (FOR), which focused on keeping the river healthy among other missions. One of their primary concerns regarding the health of the river was the decline of migratory fish stocks, such as American shad, hickory shad, blueback herring, and striped bass that were once so plentiful in the Chesapeake Bay watershed.