Thursday, 9 February 2017

Virgin Falls Dam

Virgin Falls

from the Nipigon Historical Museum Archives

" In 1924, a survey of the proposed damsite was completed.  In 1926, the Commission built a control dam at Virgin Falls, at the outlet of Lake Nipigon, creating the largest storage reservoir in existence at that time, with a capacity of 6,700,000 acre feet. "

"Order-in-Council dated April 25, 1930, approved construction of control dam to maintain Lake Nipigon level of 855; approved amount $486,884.26. The control dam consisted of a concrete pier and stop-log structure (nine sluices, 15 feet deep, 5 feet freeboard) across the main channel together with an additional three sluice ways located in the left bank diversion channel. Total design discharge for the structure was 10,000 cfs (cubic feet per second) at minimum lake level."

"The gravity wall section, right abutment is founded on rock with a top width of 24 inches and downstream batter of 7 and a half to 12. The gravity wall section between channels is also founded on rock, with a 12 inch top width, 7 and a half to 12 downstream batter, with the deeper sections back filled on the downstream side by rock fill ( one and a half to one slope)"

"The Pine Portage project assumed control of Lake Nipigon and all stoplogs were removed from the Virgin Falls dam. During demolition proceedings on the deck, one of the piers was demolished and the structure is no longer in an operational condition."

"Note: License of Occupation 7785 dated November 1, 1963 grants Ontario Hydro the right to occupy and maintain the damsite areas at Virgin Falls and Black Sturgeon in order to regulate the Lake Nipigon level up to  elevation 855 feet. Land involved at Virgin Falls is 5.1 acres and at Black Sturgeon 13.63 acres."

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