Nipigon River



The Nipigon River, famous for the quantity and size of its brook trout, is home to many fish species as well. Upstream from Alexander Dam, the river provides habitat for brook trout, lake trout, walleye, lake whitefish, northern pike and most recently, smelt. Alexander Dam blocks fish migration from Lake Superior. The lower section of Nipigon River is home to most of the species in Lake Superior including coaster brook trout, lake trout, walleye, northern pike, smelt, lake whitefish, sea lamprey, brown trout, rainbow trout and Pacific salmon species.

River tributaries flowing into Lake Nipigon provide important spawning habitat for brook trout, walleye, smelt, suckers and to a lesser extent, lake whitefish and sturgeon. Northern pike use the wetlands along the mouths of many tributaries for spawning.   On the Nipigon River, over-fishing in the 1800s and the creation of dams from the 1920s to the 1950s, lead to habitat destruction and fluctuating water levels. A brook trout rehabilitation plan was developed in 1989, and various fisheries management programs have taken place since then in an effort to protect brook trout populations and improve water levels. Brook trout, northern pike, lake trout, Chinook salmon, whitefish and smelts are still commonly sought fish today. 

The Nipigon River will be managed for a high quality brook trout fishery, with the intent of maximizing the opportunity to catch a memorable sized fish. Angling pressure is still high in the river, with preliminary results of an angler tagging study showing brook trout recapture rates as high as 50%, meaning one out of every two brook trout is caught. The entire length of the Nipigon River receives high angling pressure, especially the brook trout stocks at Virgin Falls.


Nipigon River flow rate


The chart above, comes from the Ontario Power Generation site for the Alexander dam. It shows the monthly flow rates for the Nipigon River. The summer flow rate is 560 cms or 19,000 cf/s.

This is the equivalent of filling an Olympic sized swimming pool is 4.5 seconds.


Alexandria Rapids prior to the dam construction


Nipigon River video (circa 1923)

Produced by the Government of Canada. It is an interesting look back in time at the travellers, transportation methods and the ruggedness of the river before any dam construction.

Alexander Dam built in 1930


The Alexander dam has stopped the upstream migration of exotics such as sea lamprey, alewife, carp, brown trout, rainbow and salmon species. This lower section of the river provides some of the most important spawning habitat (Gapen’s Pool) for the largest remnant population of the famous “coaster” brook trout of Lake Superior.


Power Development

The need for hydro electric power changed the Nipigon for ever


Power development began in the Nipigon Signature Site in 1918 with the building of the Cameron Falls Dam on the Nipigon River. In 1925 and 1930 two more dams, the Virgin Falls and the Alexander Dams were built "to enable the total flow of the Nipigon River to be utilized for power development"

Virgin Falls, was built in 1925 to control water levels on Lake Nipigon. This dam created the largest reservoir in existence and raised Lake Nipigon by 15 cm (0.48 ft). The Ogoki River Diversion was initiated in 1940. The Waboose Dam, built on the Ogoki River in 1942, diverted water flowing north to the Albany River and directed it south through the Nipigon Basin to increase the power output at Niagara Falls.  The Ogoki Diversion on the Ogoki River raised the lake level by 35 cm and increased the flows by 50% in the Nipigon River. The existing power plants on the  Nipigon River could not effectively harness this increased output, so the Pine Portage Dam was built in the 1950’s and it too raised the water level of Lake Nipigon by 12 cm, flooding over the Virgin Falls Dam.

The completion of the Pine Portage Dam in 1950 raised the water level on the Nipigon River by 31 metres (100 feet) and flooded out almost 16 kilometres of white water, rapids and waterfalls including the White Chutes, Victoria, Canal, Devil, Rabbit and Miner’s Rapids. Lake Emma and Hannah were both flooded out and the whole area was renamed Forgan Lake.


'Nepigon' River Map (prior to 1923)....................... Nipigon River Map(post 1950)


Here are two maps of the upper Nipigon River. On the left, is the map of the Nipigon River in 1921 before any dams destroyed the illustrious rapids, pools and falls. On the right, is a similar scaled map, circa 1972, as it appears today.

In 1990 an interim flow agreement was reached to minimize damage to brook trout spawning beds.
A Nipigon River Water Management Strategy was developed in 1994.


Gapen's Pool

The Gapen family is part of the Nipigon legend. Here is a link to their history including Don Gapen's world famous Muddler Fly.

The History of Gapen

Gapen's Pool as seen by the air, is a significant spawning site for coaster brook trout. Because the surrounding land provides a hydrological function collecting, storing, filtering, and percolating groundwater which then supplies the underwater springs that these trout need for successful reproduction, the pool is designated as a "fish sanctuary" under the regulations.


While the decline in numbers of this legendary fish on the north shore of Lake Superior has been reversed due to the minimizing of water level fluctuations on the Nipigon River, the trout now face an equally serious problem, and that is the potential loss of one of only three major spawning sites on the Nipigon River. One of these major spawning sites, the water known as Gapen’s Pool was purchased in the spring of 2007 by Trout Unlimited Canada to protect this valuable resource.  This land serves a critical hydrological function collecting, storing, filtering, and percolating groundwater which then supplies the underwater springs that these trout need for successful reproduction.

Gapen's Pool

This relationship has been confirmed through a hydrological study conducted by R. A. Curry et al in 1994.

The following summary comes from the  "Nipigon River Land Acquisition Proposal...Gapen's Pool"

• Gapen's Pool is one of only three spawning sites identified for this species on the Nipigon River and attracts lake dwelling trophy fish from across Nipigon Bay and beyond.

• Coaster brook trout have very specific spawning needs and require sites with substantial underwater springs for successful reproduction.

• The land adjacent to these spawning locations serve a critical hydrological function filtering, collecting, storing and percolating groundwater into these seepage areas beneath the river.

• The purpose of the acquisition is to acquire the property adjacent to the east portion of Gapen’s Pool to protect and conserve critical functions that this property provides to Coaster Brook Trout in the Nipigon River.

• The only relatively healthy population of Coaster brook trout in Lake Superior is now concentrated in the Nipigon Bay and Nipigon River.

• Brook trout require groundwater discharge areas of significant volume and extent for spawning. Brook trout eggs require constant groundwater discharges of uniform temperature in order to incubate and hatch.

• The lands adjacent to the spawn beds make up a major portion of the catchment area and groundwater recharge zone which filters and percolates surface waters leading to the creation of upwelling, groundwater seepage areas along the base of the banks of the Nipigon River

• In the fall of the year at 3 special habitats of the river, female trout returning to the river dig nests and bury their eggs in gravel substrates where embryos remain until spring when juveniles emerge into the river. During this 4 month period in the gravel, the embryos are bathed in groundwater that flows through the gravel because of special geologic characteristics of the bank and adjacent lands. Our research has shown that the reproductive habitats in the river are sustained by the groundwater and therefore, the habitats are directly linked to the adjacent landscape which controls the pathways and flow rates of groundwater to the river at these critical habitats