- Liard River

The Liard River, with a total drainage basin of some
106,000 square miles, is one of the principal tributaries of
the Mackenzie. It rises in Yukon Territory and flows
south into British Columbia just above its confluence with
the Dease. It then flows through that Province for a
distance of 270 miles, and, after passing through the Rocky
Mountains, turns northward again, enters the Northwest
Territories, and joins the Mackenzie River at Fort Simpson.
From the elevated country to the west of the Rocky
Mountains, the Liard River falls rapidly toward the east,
the difference in elevation between the mouth of the Dease
River and the Mackenzie River being estimated at 1,650 feet,
of which over 1,000 féet is said to occur in 200 miles of the
river in British Columbia. The descent is greatest and
rapids are most numerous in the course through, and for

some distance on each side of, the Rocky Mountains. This

reach is characterized by many narrow, rocky canyons.
The river is navigable for a distance of about 300 miles
from near its mouth to Hell’s Gate, where the canyon
reaches begin. The principal tributaries of the Liard are

the Frances, Dease, Turnagain, Kechika, Coal, Fort Nelson,
and South Nahanni Rivers.

Water Supply.—Records of flow of the Liard and of
several of its tributaries were initiated in 1944, but these
are as yet too limited for estimating purposes. It is known,
however, that its flow characteristics are similar to those
of the Peace and Athabaska. All are mountain-fed rivers,
the flows of which reach a minimum in the winter months
and a maximum in the period May to July, when high
temperatures and rains release water from glaciers and
accumulated snow in the mountain areas. In the absence
of actual records of discharge, the run-off in the Liard River
has been assumed as 0-16 c.f.s. per square mile under
conditions of ordinary minimum flow, and 0-56 c.f.s. per
square mile ordinarily available for six months of the year.
These factors have been deduced from a study of run-off
records of the Peace and Athabaska Rivers and from
precipitation records.

Lakes offering possibilities as storage reservoirs are
small and are situated for the most part at or near the
headwaters of various tributaries. Opportunities for
effective regulation of the Liard River flow, accordingly,
are not promising, unless storage can be provided by the
flooding of the main river valley by the construction of
high dams if conditions permit.

Power Resources.—No development of water power has
as yet taken place within the Liard River basin, and no
investigations have been made cf undeveloped resources.
Any estimates of the power potentialities, therefore, are
based on very meagre information, and must be considered
as general approximations only.

There is said to be a descent of more than 1,000 feet
in the 200-mile reach of the Liard in British Columbia,

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176 I

and in this reach there are numerous rocky canyons. These
canyons suggest opportunities for concentrations of head by
the construction of dams. The feasibility of such con-
centrations could only be determined by field examinations,
but assuming that it might be possible to develop 800 feet of
the total descent at various suitable locations, it would
appear that the Liard has power potentialities of more than

400,000 horse-power at ordinary minimum flow, or 1,500,000

horse-power at ordinary six months flow. These flows
were estimated on the basis previously mentioned under
the heading “Water Supply”.

Specific information is lacking concerning the descent -
of the various tributaries of the Liard, except the South
Nahanni River, on which Virginia Falls is reported to
have an abrupt fall of 316 feet. Tributaries in the mountain-
ous portion of the basin such as the Frances, Dease, Turna-
gain, and Coal Rivers, undoubtedly offer opportunities for
development by concentration of head through the con-
struction of dams, but information is too meagre to permit
even an approximate estimate of their power. potentialities.
Virginia Falls on the South Nahanni has power possibilities
of possibly 5,000 horse-power at ordinary minimum flow,
or 13,000 horse-power at ordinary six months flow.

Power Markets.—No power markets of any significance
are at present apparent in the Liard River basin. Any
developments that might be undertaken on the Liard itself
would require markets for large blocks of power. The reach
of the Liard where power resources are indicated is some
300 miles distant by air line from the Pacific Coast or from

-Whitehorse, a distance probably too great for economical

transmission having in mind the difficult nature of the
country to be traversed. Local requirements, therefore,
based on the mineral resources of the region, would appear
to offer the most probable possibilities for power markets.

For smaller power demands the tributaries would need to
be examined for suitable sites.

Peace River

The Peace River, draining an area of 119,000 square
miles, is the largest tributary of the Mackenzie drainage
system. It is formed in the great intermontane valley,
to the west of the main range of the Rocky Mountains,
by the junction of the Parsnip and Finlay Rivers and,
flowing eastward, cuts through the axis of that range and
drains a large area on its eastern slope. Leaving the
mountains and foothills, it enters the northerly extension
of the Great Plains Region, through which it flows in a
generally easterly direction to its junction with the Rivigre
des Rochers, which drains Lake Athabaska, to form the Slave
River. The total length of the Peace below the junction
of the Finlay and the Parsnip is 820 miles, and the total
fall in this distance is about 1,300 feet. Nearly one-half
of the drainagé area is in the mountainous Cordilleran

Region, and the remainder forms part of the Great Central
Plain of Canada.