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Updated December 15, 2009, 10:01 pm

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Au Sable River

A world-famous trout stream, the Au Sable River runs about 80 miles from near Grayling to Lake Huron. Along the river’s eastward flow, Consumers Energy operates six hydroelectric dams: Mio, Alcona, Loud, Five Channels, Cooke and Foote.

The hydros were built between 1911 and 1924. Together, they can generate 41,000 kilowatts of electricity, enough to power a community of about 20,500 people.

How it Works

 How a Hydroelectric Dam Generates Electricity

Mio Hydro

With a capacity of 4,900 kilowatts, the hydro was built between 1914-16 and is the company’s hydro furthest upstream (west) on the Au Sable River.

Named after the nearby city, Mio was the first hydroelectric plant to use a conduit or under-sluice spillway. Before this, all dams had included a massive above-ground concrete spillway that typically included a system of gates to pass excess flows. The under-sluice spillway was built into the powerhouse foundation and eliminated the need for the above-ground structure. The under-sluice spillway was invented and patented by William W. Tefft, a Consumers civil engineer and vice president.

Tefft’s innovation reduced tailwater erosion during spill operation, increased the plant’s power production and reduced construction expense. It was refined and used at subsequent Consumers’ projects at Alcona Hydro on the Au Sable River, at Hodenpyl Hydro on the Manistee River and at Hardy Hydro on the Muskegon River.

Oscoda County Park is the perfect place for scenic views of the Mio dam and watching bald eagles soar above the forest, with 153 campsites in a quiet forest setting on the Mio Hydro pond.

Alcona Hydro

Capable of producing 8,000 kilowatts, the hydro was originally named for a nearby road called Bamfield. Work began on Bamfield Dam in 1917, but the project stalled due to unstable sand and World War I. Construction resumed in 1923, and Alcona Hydro, named after the county where it is located, began commercial operation in 1924.

Alcona Park, on the Alcona Hydro pond, is an 1,100 acre outdoor paradise with more than 450 campsites and many special features.

Loud Hydro

Capable of producing 4,000 kilowatts, the hydro was completed in 1913. It is named for Edward Loud, who had done extensive lumber business along the Au Sable and bought up most of the cut over Au Sable lands between 1900-06, then later partnered with company founder William Foote and others to build the Au Sable hydros.

Five Channels Hydro

Capable of producing 6,000 kilowatts, the hydro was completed in 1912. This hydro is named for the nearby location on the Au Sable River where there were once five distinct river channels. The site of the workers’ camp built to support construction of the dam was listed on the National Register of Historic Places on March 13, 2002. It is an early American example of incorporating worker safety and health provisions into construction site living, drawing heavily on lessons learned in the building of the Panama Canal.

Cooke Hydro

With an original capacity of 9,000 kilowatts, the hydro began generating electricity in December 1911, making it the first of the six Au Sable River hydros. Cooke is named for banker Andrew Cooke, who helped secure financing for the project. 

Cooke Hydro was listed in the National Register of Historic Places on Aug. 2, 1996. The honor recognizes the hydro’s transmission of 140,000 volts, 125 miles to Flint, establishing a world record. Innovations included three-legged windmill-like towers that supported the transmission line and advances in insulator design. Cooke Hydro is also part of the River Road Scenic Byway and listed in the National Scenic Byways Program.

Lumberman’s Monument, a 14-foot bronze statue dedicated to Michigan lumbermen, is the centerpiece of a major Forest service visitor Center located on the Cooke Hydro pond. The site features interpretive displays, along with a panoramic overlook and staircase leading down to the pond.

Foote Hydro

With a capacity of 9,000 kilowatts, the hydro was completed in 1918. It is located 9 miles upstream from Lake Huron and is named for William A. Foote, the founder of Consumers Power, which later became Consumers Energy.

In 1896, Foote took a side trip from Kalamazoo to Allegan, where he conceived the idea of a hydroelectric plant along the Kalamazoo River. In Foote’s mind, that plant and others would power the industrial centers throughout the state.

The Au Sable River Queen on the Foote Hydro pond offers an unique paddlewheel boat cruise that combines spectacular scenery with the history and lore of the Au Sable.

Old Orchard Park on the Foote Hydro pond, operated by Oscoda Township, is a popular destination with 500 campsites and many amenities.


When Consumers Energy pioneered the development of hydroelectric power along the Au Sable, the land was ravaged by decades of logging. Between the mid-1920s and the 1950s, Consumers Energy planted millions of pine trees along the river to stabilize the banks for the six dams. The Au Sable (the name means “River of Sand”) now provides excellent fishing, recreation and wildlife viewing from Grayling to Oscoda.

Most of the river frontage is Huron National Forest land managed by the U.S. Forest Service or land owned by Consumers Energy. Consumers Energy owns about 3,500 acres and leases much of its property to public or private operators of boat rental companies, swimming areas or campgrounds.

Aspen, oak, maple, pine, balsam, spruce and cedar trees provide shelter and food for deer, wild turkey, ruffled grouse, snowshoe hares and other animals. Bald eagles nest along the river.

Portages are available at each Consumers Energy hydro, to allow recreation-seekers to canoe down the winding river or float on an inner tube. In fact, canoeing has become so popular, the Au Sable hosts an annual canoe marathon.

The Au Sable River hydroelectric projects are also included as “watchable wildlife” viewing areas in Michigan’s Wildlife Viewing Guide. Consumers Energy works with the USDA Forest Service and other entities to build and maintain these areas and assist in providing viewing opportunities.

Environmental Commitment

Wildlife habitat efforts on the Au Sable River were first certified by the Wildlife Habitat Council in 1999.

Consumers Energy manages hundreds of acres of wildlife habitat around its six hydroelectric dams along the Au Sable. In addition to meeting all of its licensing requirements, the company manages important wildlife initiatives at its Au Sable facilities, including programs that monitor bald eagles and ongoing efforts to reintroduce the familiar trumpeter swan.

The company helped reintroduce 14 native trumpeter swans to the area in 1997-1998. During December 2003, the Iosco Audubon Society counted 138 trumpeter swans on Consumers’ Alcona, Cooke and Foote reservoirs.

The company also maintains nesting structures for wood ducks, purple martin colonies, bluebirds and ospreys along the Au Sable.