Monday, April 18, 2016

The Two Spearfish Canyon Hydro Plants

Graphic of Hydro 1, south of Spearfish Park 
Paul Higbee shared the history of the "Two Spearfish Canyon Hydro Plants" to 125 people at the April 5, 2016 program for the Spearfish Area Historical Society.   
Paul Higbee speaking on "Two Spearfish Canyon  Hydro Plants"  

Hydro 1 in Spearfish
The first hydro-electric plant from Spearfish Canyon was started up 104 years ago on April 12, 1912.    Homestake Mining Company designed and built the water flow and hydro plant using its own capital without borrowing funds.  The new lower cost electrical power was to replace coal-fired steam power.  The plan was to divert water from Spearfish Creek in the canyon and send it directly to a new power plant in Spearfish.  Key people on the project were Thomas Greer and engineer, Capt. Richard Blackstone.  A dam was built at the diversion site at Maurice.  Eight tunnels were drilled 5 miles through the Spearfish Canyon rock.   The tunnel(s), at 6 ½' wide x 5' high with an arched ceiling, were coated with cement to become the conduit for the water diversion.   The tunnels narrowed towards the Spearfish end to increase water pressure as it came into Hydro Plant 1, located south of Spearfish Park.   From the dam at Maurice to the sand-pipes, the water drops 800 feet.  Drilling turned out to be easier than expected as the Spearfish Canyon rock was softer than the rock near Homestake's operations near Lead.  That advantage was countered by nature when a 1909 flood took out the railroad line in the canyon.

One of the two generators inside Hydro 1 in Spearfish
Hydro Plant 1 with two generators started up smoothly in 1912 but, by 1913, Homestead needed more power and another generator, so they designed a second plant directly in Spearfish Canyon (this is the dam and power plant that can be seen next to the highway about 6 miles up the canyon).  Man-made pipe conduit was installed through and along the canyon walls and Hydro Plant 2 was started up in 1918.  That start up caused Spearfish Falls, just below Latchstring Inn, to go dry. 

Both Hydro Plants operated through the 1934 year of dust storms.  In 1947, a Spearfish Canyon landslide damaged the conduit and Hydro Plant 2 was shut down.  The Hydro Plant 2 property was sold to SD Game, Fish and Parks.   In 2004, Homestake sold Hydro Plant 1 to the City of Spearfish.  The plant is still running and the power is sold to BH Energy.  Homestake re-channeled the water to Spearfish Falls in 1990.