Gathright Dam is an earthen and rolled rock-fill
embankment dam
An embankment dam is a large artificial dam. It is typically created by the placement and compaction of a complex semi-plastic mound of various compositions of soil or rock. It has a semi-pervious waterproof natural covering for its surface and ...
on the
Jackson River north of
Covington, Virginia
Covington is an independent city in the Commonwealth of Virginia. As of the 2020 census, the population was 5,737, making it the second-least populous city in Virginia. It is surrounded by Alleghany County, of which it is also the county seat. ...
. The dam is tall and long and has a controlled
spillway
A spillway is a structure used to provide the controlled release of water downstream from a dam or levee, typically into the riverbed of the dammed river itself. In the United Kingdom, they may be known as overflow channels. Spillways ensure tha ...
within the structure's southern portion. It creates Lake Moomaw, which has a normal volume of . The dam serves
flood control
Flood control methods are used to reduce or prevent the detrimental effects of flood waters."Flood Control", MSN Encarta, 2008 (see below: Further reading). Flood relief methods are used to reduce the effects of flood waters or high water level ...
and recreational purposes and is operated by the
U.S. Army Corps of Engineers
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.
The Gathright Dam's
intake tower
An intake tower or outlet tower is a vertical tubular structure with one or more openings used for capturing water from reservoirs and conveying it further to a hydroelectric or water-treatment plant.
Unlike spillways, intake towers are intended ...
contains nine portals that allow it to release water between reservoir depths of . This allows the dam to manage the temperature and flow of water released downstream. This helps mitigate some of the negative environmental effects posed by the dam and manage fisheries downstream.
History and construction
The Gathright Dam was authorized by
Congress
A congress is a formal meeting of the representatives of different countries, constituent states, organizations, trade unions, political parties, or other groups. The term originated in Late Middle English to denote an encounter (meeting of a ...
with the
Flood Control Act of 1946 The Flood Control Act of 1946 was passed by the United States Congress on July 24, 1946; to authorize 123 projects including several dams and hydroelectric power plants like Old Hickory Lock and Dam in Tennessee and the Fort Randall Dam in South Da ...
to provide flood protection of industrial, commercial and residential properties along the Jackson and James Rivers, with immediate impact on Covington, Virginia.
Benjamin Cline Moomaw, Jr., a Virginian businessman who was influential in gaining approval for the project and is known locally as "the Father of the Gathright Dam" is the namesake for the lake. The dam itself is named after Thomas Gathright, who owned the land that was flooded by the reservoir.
Because of setbacks though, construction did not begin until 1974. The dam was finished in 1979 and that December, Lake Moomaw began to fill. The
reservoir
A reservoir (; from French ''réservoir'' ) is an enlarged lake behind a dam. Such a dam may be either artificial, built to store fresh water or it may be a natural formation.
Reservoirs can be created in a number of ways, including contro ...
was filled by April 1982. Filling of the reservoir displaced the small town of
Greenwood which had been located at what is now the southern part of Lake Moomaw.
The reservoir reached its highest elevation in 1996 at above sea-level.
Environmentalists and the EPA challenged the plan for construction on grounds that the scenic Kincade Gorge and important historical and archaeological sites would be destroyed by the lake. Contesting parties suggested that the dam was constructed for the benefit of the Westvaco paper plant downstream that relied on a regular flow of water to operate.
Instability concerns
In May 2009, the
U.S. Army Corps of Engineers
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(USACE) inspected the Gathright Dam as part of Screening Portfolio Risk Analysis and routine inspections. Later in the year on September 2, the USACE assigned the dam a Safety Action Classification (DSAC) II which is defined as "Urgent (Unsafe or Potentially Unsafe)". The rating is attributed to concerns about possible increased seepage at the toe of the dam, and an undetermined flow rate at the river spring downstream, and potential flow channels through
limestone
Limestone ( calcium carbonate ) is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of . Limestone forms whe ...
below the spillway during pool events above .
Because of this rating, the USACE has implemented risk reduction measures which include increased monitoring, updating emergency operation plans and reducing the water level in the reservoir. As of early 2010, the USACE has reduced and continues to maintain the reservoir at an elevation of above sea level compared to the normal level of . Throughout 2010, the USACE conducted safety exercises with local/state officials, conduct a series of investigations on the dam, update inundation mapping and reevaluate the DSAC status. In November 2010, Lake Moomaw was restored to a level of and the DSAC will be reevaluated in the future.
References
External links
USACE - Gathright Dam Action PlanGathright Historic- USACE photo album from construction
Lake Moomaw Water Level
{{authority control
Dams in Virginia
Buildings and structures in Alleghany County, Virginia
Embankment dams
United States Army Corps of Engineers dams
Dams completed in 1979
Moomaw
George Washington and Jefferson National Forests
Bodies of water of Alleghany County, Virginia
Bodies of water of Bath County, Virginia