Ripogenus Gorge

Ripogenus Gorge
1870s view of Ripogenus Gorge
Location	Northeast Piscataquis, Piscataquis County, Maine, USA
Long-axis length	10 miles (16 km)
Width	700 feet (210 m)
Geography
Coordinates	45°52′33″N 69°09′00″W / 45.8759°N 69.15°W / 45.8759; -69.15Coordinates: 45°52′33″N 69°09′00″W / 45.8759°N 69.15°W / 45.8759; -69.15
Watercourses	West Branch Penobscot River

Ripogenus Gorge is a rock-walled canyon formed where the West Branch Penobscot River crosses the Caribou Lake anticline. Ripogenus Falls controlled discharge from Ripogenus Lake until Ripogenus Dam was completed at the upstream end of the gorge in 1916. The dam forms a hydroelectric reservoir raising the level of Ripogenus Lake to include the upstream Chesuncook Lake, Caribou Lake, and Moose Pond. The resulting reservoir is often identified by the name of the largest included lake: Chesuncook. The gorge provides an unusual exposure of Maine North Woods bedrock typically covered by saturated glacial till. The Silurian Ripogenus Formation of weakly metamorphosed shallow marine siliciclastics and fossiliferous limestone has been described from investigation of the gorge.^[1]

History

Spruce forests along the west branch were harvested through the 19th century with logs floated through the gorge to sawmills as far downstream as Bangor, Maine. Log driving rivermen altered the gorge with dynamite and timber cribs filled with stone to prevent log jams. Construction of Ripogenus Dam began in 1915 to provide hydroelectricity for the paper mill at Millinocket, Maine. The dam is 92 feet (28 m) high and 704 feet (215 m) long and impounds the largest storage reservoir ever built with private funding. Hydroelectricity is generated by diverting 2,400 cu ft/s (68 m³/s) through a mile-long penstock around the former falls. Pulpwood was sluiced over the dam until 1971 when Great Northern Paper Company began trucking the lumber to the mill via the Golden Road.^[2]

Whitewater recreation

Penstock releases through the gorge create a popular whitewater run through class IV rapids with a class IV+ boulder garden. Rafts and kayaks navigate between rock cliffs through colorfully named Exterminator Hole (IV), Staircase (IV), Fist of God, Big Heater, Little Heater, Troublemaker Hole (III+), Cribworks (V), Turkey Chute, Final Chute, Postage Stamp Rock, and Bonecruncher (III).^[3]

References

↑ "Silurian Ripogenus Formation". United States Geological Survey. Retrieved 2012-12-29.
↑ "The Northern: The Way I Remember" (PDF). John E. Mcleod. Retrieved 2012-12-19.
↑ "Penobscot River - West Branch Ripogenus Gorge". Retrieved 2012-12-29.

Penobscot River Watershed

Tributaries	Dead River East Branch Mattawamkeag River East Branch Penobscot River East Branch Piscataquis River East Branch Pleasant River Kenduskeag Stream Little Seboeis River Mattawamkeag River Middle Branch Pleasant River Molunkus Stream Narramissic River North Branch Marsh River North Branch Penobscot River Orland River Passadumkeag River Piscataquis River Pleasant River Sebec River Seboeis River South Branch Marsh River South Branch Penobscot River Stillwater River West Branch Mattawamkeag River West Branch Penobscot River West Branch Piscataquis River West Branch Pleasant River

Lakes	Allagash Lake Canada Falls Lake Caucomgomoc Lake Chamberlain Lake Chesuncook Lake Cold Stream Pond Debsconeag Lakes Grand Lake Seboeis Jo-Mary Lakes Lobster Lake Lower Wilson Pond Matagamon Lake Mattawamkeag Lake Millinocket Lake Nahmakanta Lake Nicatous Lake Lake Onawa Pemadumcook Chain of Lakes Pleasant Lake Pushaw Lake Ragged Lake Rainbow Lake Schoodic Lake Sebec Lake Seboeis Lake Seboomook Lake South Twin Lake Telos Lake Toddy Pond Upper Wilson Pond

Towns	Abbot Bangor Bradley Brewer Brooks Brownville Bucksport Burlington Carmel Charleston Danforth Dover-Foxcroft East Millinocket Eddington Enfield Frankfort Guilford Hampden Haynesville Hermon Howland Hudson Island Falls Kenduskeag Kingman Lee Levant Lincoln Macwahoc Mattawamkeag Medway Milford Millinocket Milo Monson Oakfield Old Town Orland Orono Orrington Passadumkeag Patten Prospect Sangerville Sherman Smyrna Springfield Veazie Verona Winn Winterport Wytopitlock

Landmarks	Bangor and Aroostook Railroad Baxter State Park Fort Knox Gero Island Great Northern Paper Company Great Works Dam Hundred-Mile Wilderness Katahdin Iron Works Maine Central Railroad Monson Railroad Mount Katahdin North Maine Woods Orono Dam Peaks-Kenny State Park Penobscot Indian Island Reservation Penobscot Narrows Bridge and Observatory Ripogenus Gorge Stillwater Dam University of Maine Veazie Dam Waldo–Hancock Bridge

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