Narrows Dam
Encyclopedia
Narrows Dam is a dam
located 6 miles north of Murfreesboro, Arkansas
, that impounds the water of the Little Missouri River (Arkansas)
to create Lake Greeson
. Narrows Dam was authorized as a flood
control and hydroelectric power project by the Flood Control Act of 1941
. The dam is a feature of the comprehensive plan for the Ouachita River
Basin. Lake Greeson is operated for hydroelectric power, recreation, and flood control. http://www.arkansas.com/images/photos/large/lakegreeson_009_l.jpg
The powerhouse of the dam is located adjacent to the east abutment, and it has a total length of 151 feet. The equipment of the powerhouse is three 8,500 kW·h generating machines. The powerhouse originally had two generators, but a third was placed in 1969. The average annual output is 28,000,000 kW·h.
The dam is named due to its location on the river, The Narrows. During the dam's construction many cemeteries
and graveyards had to be removed due to the creation of the new lake. Narrows Dam is located by the Swaha, or Narrows Dam recreational area.
Lake Greeson is divided into three layers so Narrows Dam can work and operate properly. The bottom portion of the lake always remains full so the powerhouse has enough pressure to operate. The middle layer or "Power Storage" portion is used to regulate the flow of water running into the generators of the dam. The top portion or "Flood Storage" is usually empty unless holding floodwater.
A spillway
at the top of the dam is used to regulate the top portion of the dam, the spillway contains walls to maneuver the flow of the water, and a stilling basin is placed at the foot of the spillway to dissipate erosion
from the spillway water hitting the base of the dam. The spillway is not used frequently because flooding can be regulated by other means, such as the flood control conduits. Because of heavy rains during the first two weeks of May 2009, water poured over the spillway for the first time since 1968.
Construction on the dam began on April 1947. The first bucket of concrete
was poured in June 1948. The dam was finished in 1950, and dedicated in July 1951.
Dam
A dam is a barrier that impounds water or underground streams. Dams generally serve the primary purpose of retaining water, while other structures such as floodgates or levees are used to manage or prevent water flow into specific land regions. Hydropower and pumped-storage hydroelectricity are...
located 6 miles north of Murfreesboro, Arkansas
Murfreesboro, Arkansas
Murfreesboro is a city in Pike County, Arkansas, United States. The population was 1,764 at the 2000 census. The city is the county seat of Pike County....
, that impounds the water of the Little Missouri River (Arkansas)
Little Missouri River (Arkansas)
The Little Missouri River, or Little Mo, is a waterway that runs from the Ouachita Mountains of southwest Arkansas into the rolling hills area in the surrounding countryside.- Overview :...
to create Lake Greeson
Lake Greeson
Lake Greeson is a reservoir on the Little Missouri River, about north of Murfreesboro, Arkansas. Famous for its scenery and recreation, it is surrounded by 15 parks that offer opportunities for camping, fishing, boating, biking, and swimming.- Overview :...
. Narrows Dam was authorized as a flood
Flood
A flood is an overflow of an expanse of water that submerges land. The EU Floods directive defines a flood as a temporary covering by water of land not normally covered by water...
control and hydroelectric power project by the Flood Control Act of 1941
Flood Control Act of 1941
The Flood Control Act of 1941 was an Act of the United States Congress signed into law by President Franklin Delano Roosevelt that authorized civil engineering projects such as dams, levees, dikes, and other flood control measures through the United States Army Corps of Engineers and other Federal...
. The dam is a feature of the comprehensive plan for the Ouachita River
Ouachita River
The Ouachita River is a river that runs south and east through the U.S. states of Arkansas and Louisiana, joining the Tensas River to form the Black River near Jonesville, Louisiana.-Course:...
Basin. Lake Greeson is operated for hydroelectric power, recreation, and flood control. http://www.arkansas.com/images/photos/large/lakegreeson_009_l.jpg
The powerhouse of the dam is located adjacent to the east abutment, and it has a total length of 151 feet. The equipment of the powerhouse is three 8,500 kW·h generating machines. The powerhouse originally had two generators, but a third was placed in 1969. The average annual output is 28,000,000 kW·h.
The dam is named due to its location on the river, The Narrows. During the dam's construction many cemeteries
Cemetery
A cemetery is a place in which dead bodies and cremated remains are buried. The term "cemetery" implies that the land is specifically designated as a burying ground. Cemeteries in the Western world are where the final ceremonies of death are observed...
and graveyards had to be removed due to the creation of the new lake. Narrows Dam is located by the Swaha, or Narrows Dam recreational area.
Lake Greeson is divided into three layers so Narrows Dam can work and operate properly. The bottom portion of the lake always remains full so the powerhouse has enough pressure to operate. The middle layer or "Power Storage" portion is used to regulate the flow of water running into the generators of the dam. The top portion or "Flood Storage" is usually empty unless holding floodwater.
A spillway
Spillway
A spillway is a structure used to provide the controlled release of flows from a dam or levee into a downstream area, typically being the river that was dammed. In the UK they may be known as overflow channels. Spillways release floods so that the water does not overtop and damage or even destroy...
at the top of the dam is used to regulate the top portion of the dam, the spillway contains walls to maneuver the flow of the water, and a stilling basin is placed at the foot of the spillway to dissipate erosion
Erosion
Erosion is when materials are removed from the surface and changed into something else. It only works by hydraulic actions and transport of solids in the natural environment, and leads to the deposition of these materials elsewhere...
from the spillway water hitting the base of the dam. The spillway is not used frequently because flooding can be regulated by other means, such as the flood control conduits. Because of heavy rains during the first two weeks of May 2009, water poured over the spillway for the first time since 1968.
Construction on the dam began on April 1947. The first bucket of concrete
Concrete
Concrete is a composite construction material, composed of cement and other cementitious materials such as fly ash and slag cement, aggregate , water and chemical admixtures.The word concrete comes from the Latin word...
was poured in June 1948. The dam was finished in 1950, and dedicated in July 1951.