Safe Harbor Dam

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Safe Harbor Dam
The east end of the turbine hall for the Safe Harbor Dam housing the 25 Hz turbines.
Official nameSafe Harbor Hydroelectric Station
LocationManor Township, Lancaster County / Chanceford Township, York County, Pennsylvania, USA
Coordinates39°55′14″N 76°23′33″W / 39.92056°N 76.39250°W / 39.92056; -76.39250Coordinates: 39°55′14″N 76°23′33″W / 39.92056°N 76.39250°W / 39.92056; -76.39250
Construction began1 April 1930
Opening date7 December 1931
Dam and spillways
Type of damGravity
ImpoundsSusquehanna River
Height23 m (75 ft)
Length1,484 m (4,869 ft)
Spillway typeService, controlled
Spillway capacity1,120,000 cu ft/s (31,715 m3/s)
CreatesLake Clarke
Power Station
Turbines7 × 33.0 MW
5 × 37.5 MW
2 × 2 MW
Installed capacity422.5 MW

The Safe Harbor Dam (also Safe Harbor Hydroelectric Station) is a concrete gravity dam, with an associated hydroelectric power station, on the lower Susquehanna River. It is the most northerly and last of three Great Depression-era public electrification projects' hydroelectric dams, and was constructed between 1 April 1930 and 7 December 1931. It created a long and relatively shallow lake, known as Lake Clarke, along the upper stretch of the Conejohela Valley. The creation of the lake shrank the upper Conejohela Flats in size.

Base terrains[edit]

The mixed marshy terrain of the Conejohela Valley contained rapids and small waterfalls, wetlands, and thick woods along both sides of the river within a ten-year floodplain which saw annual inundations all the way down into Maryland at the headwaters of Chesapeake Bay, and experienced catastrophic floods regularly (the meaning of a ten-year floodplain). The varied terrain created many interface zones biologically nurturing a great many species. Many of those habitats effectively created difficult walking and horseback terrains, which stifled east-west crossing of the lower Susquehanna in colonial Pennsylvania-Maryland, spurring the 1730 opening of the historic Wright's Ferry and (later the first two) Columbia-Wrightsville Bridges, once believed to be the longest covered bridges in the world.


The dam is located just above the confluence of the Conestoga River with the Susquehanna, about 7 miles downstream of Washington Boro, Pennsylvania, which at mid-river is figured more or less the center of Lake Clarke[1] created by the dam – which has become very popular for water sports and fishing. Ecologically, the varying depth of inundated islands on the bottom of the lake create a succession of valuable varied habitats that support numerous freshwater feeder fish, pan fish, and large predatory game fish species. Thus, bird-small animal habitat that was lost was replaced, by and large, by freshwater marine habitats.

Operating company[edit]

LS Power Group purchased PPL's share in 2011, and was subsequently purchased in March 2014 by Brookfield Renewable Inc. In May 2014, Brookfield purchased Exelon's share, gaining full ownership.[2] The Safe Harbor Water Power Corporation operates the dam and power plant.

Planning and construction[edit]

Planning for the construction of the Safe Harbor Dam started in 1929, and construction started 1 April 1930. The dam was completed and closed its gates for the first time on 29 September 1931. The first power was generated on 7 December 1931, and the last of the original seven turbine generator units came on-line on 14 October 1940. Planning for expansion of the generation capacity started in 1981. Construction started 12 April 1982, and the 5 new turbine generator units came on-line between 13 April 1985 and 12 April 1986. Units 1 and 2 are Kaplan turbines connected to single-phase generators to produce 25 Hz single-phase electric power for railroad use by Amtrak and SEPTA, but also can be connected to a motor-generator to convert any spare 25 Hz power to 60 Hz. The rest of the units generate 60 Hz, three-phase power. Safe Harbor can generate 417.5 megawatts of hydroelectric power.[3] Power from Safe Harbor is dispatched through PJM Interconnection, one of many regional transmission organizations feeding the nations power grids.

Key events[edit]

On 18 May 2001, President George W. Bush visited the Safe Harbor Hydroelectric plant to expound on his just-unveiled National Energy Policy.[4][5] Safe Harbor was chosen as an example of government, corporate, and environmental groups working together in energy generation.

In 2001, Safe Harbor Water Power Corporation won the Governor's Award for Environmental Excellence. The award citation states that Safe Harbor had removed over 11,000 tons of debris from the river and was able to recycle almost all of it.[6]

See also[edit]


  1. ^ "Conejohela Valley (homepage, directory)". Conejohela Valley Chamber of Commerce. Retrieved 2010-11-29.
  2. ^ "Exelon Sells Its Share of Safe Harbor Hydro". RTO Insider. 2014-05-20. Retrieved 6 October 2015.
  3. ^ "Facts & Figures". Safe Harbor Water Power Corporation. Retrieved 2006-07-22.
  4. ^ "GOV. RIDGE JOINS PRESIDENT BUSH TO UNVEIL NATIONAL ENERGY POLICY". Archived from the original on 2006-09-24. Retrieved 2006-07-22.
  5. ^ "Safe Harbor Power Plant; Where the Environment and Civilization Swim Together". Retrieved 2006-07-22.
  6. ^ "The 2001 Governor's Award for Environmental Excellence". Archived from the original on January 17, 2006. Retrieved 2006-07-22.

External links[edit]