Safe Harbor Dam
| Safe Harbor Dam | |
|---|---|
The east end of the turbine hall for the Safe Harbor Dam housing the 25 Hz turbines.
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| Official name | Safe Harbor Hydroelectric Station |
| Location | Manor Township, Lancaster County / Chanceford Township, York County, Pennsylvania, USA |
| Coordinates | 39°55′14″N 76°23′33″W / 39.92056°N 76.39250°WCoordinates: 39°55′14″N 76°23′33″W / 39.92056°N 76.39250°W |
| Construction began | 1 April 1930 |
| Opening date | 7 December 1931 |
| Operator(s) | SHWP |
| Dam and spillways | |
| Type of dam | Gravity |
| Impounds | Susquehanna River |
| Height | 23 m (75 ft) |
| Length | 1,484 m (4,869 ft) |
| Spillway type | Service, controlled |
| Spillway capacity | 1,120,000 cu ft/s (31,715 m3/s) |
| Reservoir | |
| Creates | Lake Clarke |
| Power station | |
| Turbines | 7 × 33.0 MW 5 × 37.5 MW 2 × 2 MW |
| Installed capacity | 422.5 MW |
The Safe Harbor Dam (also Safe Harbor Hydroelectric Station) is a concrete gravity dam on the lower Susquehanna River with an associated hydroelectric power station. 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 along the upper stretch of the Conejohela Valley known as Lake Clarke. The creation of the lake shrank the upper Conejohela Flats in size.
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 and 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 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 fresh water feeder fish, pan fish, and large predatory game fish species and so loss in bird-small animal habitat was replaced by and large, in freshwater marine habitats.
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