The Granite Falls Dam was built in the late 1800s to supply mechanical power
to a mill. It was abandoned in 1896. The City of Granite Falls bought the
dam in 1911 and installed hydro power generators. The hydro plant was recently
upgraded with more efficient equipment, resulting in a total electrical output
of 1.2-Megawatts. The city hydro plant manager suggests that this is enough
energy to supply the needs of 70% of the city.
This dam is a run of the river style dam. That is, it does not have a large
storage reservoir behind the dam. As a result, each drop of water that enters
the dam pool on a given day has to exit the dam that very same day. It also
means that in periods of lower river flow levels, the dam produces less
electrical output.
The city of Granite Falls is considering the purchase of a second abandoned
dam on the Minnesota River just downstream from the city at Minnesota Falls.
As of 2008, the city is studying the possibility of converting this dam into a
second hydroelectric plant. It has been suggested that both dams will work in
tandem to generate electricity twice from each drop of water that flows down
the river.
The photo above is looking upstream towards the downriver side of the Granite
Falls Dam from the deck of the nearby Walking Bridge. The high water flow
from the spring runoff make for a lot of noise and a surprising amount of
spray.
These two photos are looking northeast across the Minnesota River from just
below the Granite Falls Dam. The photo above is the dam spillway, while the
photo below includes a view of the dam control gate and power plant. The
bridge in the background carries Oak Street across the dam pool.
These two photos are looking east across the Minnesota River towards the dam
control gates and power plant. The output power substation is visible behind
the power plant building in the photo below.
These two photos are views from the spring food of 2010. The river is
higher than the water levels in the 2008 photos above, but it has not
significantly overflowed its banks.
