SILVERTON – The water from Arrastra Creek, unused industrially since it served to process precious metals at the Mayflower Mill 60 years ago, has been harnessed again.

This time it is powering a generator and turbine to produce electricity – part of a growing small-hydro industry. The power will light the way for tourists visiting the well-preserved mill, now a National Historical Landmark.

The water, under an estimated 1,500-foot head, powers its way through an 8-inch pipe to the mill, where the pipe forks, supplying the power plant and the town water-treatment plant behind the mill.

In the turbine – a device of few parts – the water flows across blades mounted on a shaft, making it turn. The energy produced by the rotation is collected by the generator and converted to electrical energy by means of a magnetic field.

Excess power will be sold to the San Miguel Power Association through net metering.

The 9 kilowatt power plant was the battering ram that opened the door for economic small hydro.

The San Juan County Historical Society, which had inherited the Mayflower Mill and the water rights on Arrastra Creek, 12 years ago began to think about putting the water to work at the mill.

But projects downtown took precedent, said Bev Rich, who chairs the San Juan County Historical Society.

Finally, three years ago, the society tackled licensing from the Federal Energy Regulatory Commission where the bureaucracy can be as cumbersome and lengthy as getting a Hoover Dam-sized project approved.

Licensing can cost small-hydro applicants fees in excess of what they pay for power plant hardware.

Kurt Johnson, a Telluride hydropower consultant and president of the Colorado Small Hydro Association, took the Silverton case to Washington to win legislation that streamlined the process to license small hydro plants, Rich said.

A $90,000 grant from the Colorado Historical Fund covered the bulk of expenses, Rich said. The 25 percent local match came from a U.S. Department of Agriculture program and other sources, including the Colorado Water Resources and Power Development Authority.

“We’ve made history,” Rich said.

The Mayflower Mill is connected to another historic first, Rich said. In its heyday, mill operations were among the first powered by alternating current from the Ames Hydroelectric Generating Plant near Ophir. Alternating current never had been harnessed before for industrial use.

The power output for the Mayflower Mill is dwarfed by the 5,800 kW plant at Vallecito Reservoir that produces power for Tri-State Generation and Transmission and the 8,000 kW capacity plant at Tacoma on the Animas River north of Durango operated by Xcel Energy. Even the 120 kW generating plant on Lemon Reservoir that produces power for La Plata Electric Association is many times larger.