Lake Anna is one of the largest

freshwater Fresh water or freshwater is any naturally occurring liquid or frozen water containing low concentrations of dissolved salts and other total dissolved solids. Although the term specifically excludes seawater and brackish water, it does in ...

inland

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 control ...

s in

Virginia Virginia, officially the Commonwealth of Virginia, is a state in the Mid-Atlantic and Southeastern regions of the United States, between the East Coast of the United States, Atlantic Coast and the Appalachian Mountains. The geography an ...

, covering an area of , and located south of Washington, D.C., in Louisa and Spotsylvania counties (and partially in Orange County at the northern tip). The lake is easily accessible from Fredericksburg, Richmond, Charlottesville, Northern Virginia, and Washington, D.C., and is one of the most popular recreational lakes in the state.

History

The

is formed by the North Anna Dam on the

North Anna River The North Anna River is a principal tributary of the Pamunkey River, about long,U.S. Geological Survey. National Hydrography Dataset high-resolution flowline dataThe National Map accessed April 1, 2011 in central Virginia in the United States. ...

at . In 1968, Virginia Electric and Power Company (now

Dominion The term ''Dominion'' is used to refer to one of several self-governing nations of the British Empire. "Dominion status" was first accorded to Canada, Australia, New Zealand, Newfoundland, South Africa, and the Irish Free State at the 1926 ...

) purchased of farmlands in three counties along the North Anna and Pamunkey rivers to provide clean, fresh water to help cool the nuclear power generating plants at the North Anna Nuclear Generating Station adjacent to the lake. By 1972, the lake bottom was cleared of all timber, and the dam was nearing completion. It was projected to take three years to completely fill the lake, but with the additional rainfall from

Hurricane Agnes Hurricane Agnes in 1972 was the costliest hurricane to hit the United States at the time, causing an estimated $2.1 billion in damage. The hurricane's death toll was 128. The effects of Agnes were widespread, from the Caribbean to Canada, ...

, the lake was full in only 18 months. The first communities began to spring up around the lake at that time, and now some 120 different communities dot its shores. In June 1978, the first of the two reactors went into commercial operation. The second unit followed in December 1980.

Description

Lake Anna is approximately long from tip to tip, with of shoreline. The lake is divided into two sides: the public side (also known as the "cold" side) and the private side, working as a cooling pond (also known as the "hot" side). The public side is roughly , while the private side is roughly . The private side is formed of three main bodies of water, connected by navigable

canal Canals or artificial waterways are waterways or engineered channels built for drainage management (e.g. flood control and irrigation) or for conveyancing water transport vehicles (e.g. water taxi). They carry free, calm surface fl ...

s. The public and private sides are divided by three stone dikes. The private side has no marinas or public access ramps; only property owners and North Anna Power Station employees have access to the waters on the private side. The public side has several marinas and boat launches, including a boat ramp at an adjacent state park. The public side sees significantly higher boat traffic compared to the private side, especially on summer weekends. The public side is known as the "cold" side because it provides water to cool the generators at the power plant; the private or "hot" side receives warm water discharge from the power plant. The private side can be substantially warmer than the public side, especially near the discharge point, where it can be too hot for swimming. The private side has an extended water sports season. Some water circulates back out of the private side into the public side through underground channels; consequently, the public side is warmer in the southern area near the dam. In the winter, some fish migrate to these warmer waters. Preliminary steps to add a third reactor have led to protests by environmentalists and property owners, who fear a subsequent increase in the water temperature and a decrease in the water level, particularly on the private side. According to Dominion, the water discharged from the plant is usually about warmer than the intake water.

North Anna Dam

The dam creating the lake, North Anna Dam, is a and earthen embankment dam. It is wide at its crest and sits at an elevation of above sea level. The dam's spillway is located in the center of its body and is wide, containing three main and radial gates. Two smaller wide and tall gates on the outer edges of the spillway section maintain normal discharges. Normal elevation for the reservoir is . The dam's hydroelectric power plant is located on the west side of the spillway and is supplied with water via a

penstock A penstock is a sluice or gate or intake structure that controls water flow, or an enclosed pipe that delivers water to hydro turbines and sewerage systems. The term is inherited from the earlier technology of mill ponds and watermills. ...

. The plant consists of two small open runner turbine-generators, the larger with a 775 kW capacity and the smaller rated at 225 kW for a combined installed capacity of 1 megawatt.

Use and recreation

Events

Lake Anna is the site of several major annual events. The Kinetic Race weekend takes place every May; this is a half-distance race, followed by a sprint-distance race. The Giant Acorn Triathlon weekend occurs every fall and features an international/Olympic-distance triathlon, followed by a sprint-distance triathlon the following day."Giant Acorn triathlon festival"
official site. Accessed on April 5, 2010.

References