Scott Swanson
In 1984 Dave Harmon, then a bridge construction engineer for the Oregon Department of Transportation, helped one of his fellow workers rig up a miniature hydroelectric project in the guy’s back yard south of Salem.
“He had a little wintertime spring with a little waterfall and we built a mud dam for a weir and put in a 4-inch pipe and it produced enough power in the winter for three homes,” Harmon recalled.…