The moderate current which has been described as characteristic
of the Upper Pelly for some distance above the confluence,
continues to its mouth, but the Lewes is much swifter, and though
at the point of junction divided among wooded islands, is evidently
the larger stream, carrying a volume of water considerably greater
than that of the Pelly, though probably less than twice as great.
—George Dawson, 1887
Early explorers thought that the Yukon River flowed into the
Pelly rather than the other way around. This is an easy mistake to
make for at this junction the rivers seem to be of a similar size
and the flow appears to be westward, following the course of the
Pelly. As can be seen in Dawson’s quotation above, the Yukon
River above Fort Selkirk was originally called the Lewes. Geologist
George Dawson determined that it was actually the upper portion of
the Yukon River.
The glaciers that passed over this area laid down layers of
gravels and boulders. The large boulders, and the hollows made by
water cutting around them, cause the boiling effect seen in the
Yukon River. The current here is quite swift, approximately 7 kph
(4.75 mph). That, combined with the loose glacial gravel and rock,
makes for a constantly shifting river bed. As the river water
levels fluctuate with the seasons, the turbulent waters cut away
and redeposit material changing the shape and location of bars,
islands and channels. This is particularly evident at the
confluence of the two rivers where there are several large gravel
bars covered with debris washed down from both rivers. The movement
of ice also plays a major role in shaping the course of the river
as it gouges out banks and bars. At narrow places, like Victoria
Rock (Tthi Ts’et’yan or Tthi Ts’ach’an), the
ice often jams up forming dams that back water up the river valley
and cause flooding.
The constantly shifting channels and bars proved a major hazard
to sternwheelers. The ships often had to cut new channels in the
spring by aiming their paddlewheels downstream and backing their
way through the sands and gravels.
Before the sternwheelers, the river was a natural route for
First Nations people traveling north on the Yukon or east on the
Pelly. While they sometimes poled back upstream sticking to eddies
and the slower water near the bank, it was often easier just to
walk. In winter, people traveled on the ice. The ice around Fort
Selkirk is notoriously treacherous, the turbulent and swift water
often keeping patches open or very thin.
The river and its valley is also "nature’s highway"
not only for fish but for migrating birds as well. The gravel bars
near Fort Selkirk are an important resting area for migrating
birds, particularly the sandhill cranes that stop here in the
spring and autumn. The loose gravels of the Yukon River valley
allow seepings of ground water into the river and sloughs. This
makes excellent habitat for spawning Chum salmon. The waters near
the Ingersoll Islands are favourite spawning grounds for larger
chinook salmon. The isolation of the islands also makes them a
preferred calving ground for moose in the spring, a place of
sanctuary where they have some degree of safety from predators. In
the spring, the south facing hillsides of the river valley are a
favoured habitat for grizzly and black bears, as well as sheep
later in the summer. The hillsides warm early and green up quickly.
Tender shoots and roots are an important part of the ursine diet.
As the river changes course, sloughs are formed where the water
moves slower. Due to the upwelling ground water, the sloughs are
warmer in winter and cooler in summer. This is a good place to see
ducks such as the Barrow’s Goldeneye nesting and feeding. The
sloughs also support shore birds such as spotted sandpipers and the
lesser yellow legs.
The boulder and cobble bottom of the river supports a wide
variety of aquatic insects, including may flies, stone flies,
caddis flies and the dreaded black fly that spend their nymphal
stage clinging to rocks in the fast current. The insects are
particularly vulnerable when hatching or ovipositing (depositing
their eggs). At this time they provide protein rich food for the
fish and bird species of the riparian zone.
Victoria Rock marks the point where the river enters the Yukon
River gorge. While this is not a dramatic rush of white water, the
character of the river valley changes markedly from the open flats
dotted with islands seen above Fort Selkirk, to the deeper, lusher
valley seen downstream to the mouth of the White River.
The richness of life in the river valley also attracted people.
First Nation people fished and traveled seasonally along the
rivers. Once contact was made with outside traders, the river
became even more important as a transportation route. Trading posts
and settlements were built along the rivers which offered
transportation, plenty of fish and game and, often, richer soils
for growing crops.
While the third Fort Selkirk was built on a stable bench that
has not seen flooding in many generations, the river has claimed
back other settlements. A large pre-contact fish camp near Victoria
Rock has all but washed away. The original Fort Selkirk was
abandoned due to regular flooding. Often cabins built well back
from the river bank are washed away within a few decades because of
progressive bank erosion.
Figures of Interest:
- Typical open water season: May 10 - October 25
- Typical ice cover season: October 25 - May 10
- Peak water flow around June 5
- Maximum recorded water flow: 7,700 cubic metres per second
(June 25, 1962)
- Minimum recorded water flow: 227 cubic metres per second
(March 29, 1959)
Dawson, George. Report on an Exploration in the Yukon
District, Northwest Territories and Adjacent Northern Portion of
British Columbia. Whitehorse: Yukon Historical & Museum
Association, 1987 (reprint of 1888 edition)
Yukon 1992 Historical Streamflow Summary. Water Survey of
Canada, Department of the Environment, 1992.