The
Mackenzie River flows into the
Beafort Sea across a delta front
which is about 50 miles (80 km)
wide. During the dark, cold days
of winter it is hard to see that
a delta exists at all. The river
is frozen and blends in with the
flat coastal plain. But by springtime
the ice has melted, revealing
a fan shaped network of rivers,
streams, lakes, and islands. The
layout is never the same, the
sand and mud change the course
of the channels, and building
or eroding islands. The most recognizable
features are the conical mounds,
known as pingos. There are over
a thousand of these dotted around
the delta, the largest concentration
in the world. At the center of
each is a block of solid ice that
pushes up the soil into a hillock.[2]
The Mackenzie River delta begins at
Point Separation. The mean annual
discharge of Mackenzie water into
the delta, measured at the confluence
of the Arctic Red River, is 340,000
cubic feet per second, increasing
to an average of 540,000 cubic feet
per second in summer. From the south
the 425-mile Peel River is the last
major tributary of the Mackenzie,
although it actually flows into the
Mackenzie delta to the west of Point
Separation. The delta covers about
4,700 square miles and is a maze of
branching, intertwining channels,
numerous cutoff lakes, and circular
ponds. These lakes are an excellent
habitat for muskrat, and the trapping
of these animals became the main source
of income for the Indian and Eskimo
inhabitants of the delta in the period
1920–60.
The perpetually frozen subsurface
known as permafrost lies a few feet
beneath the surface of the islands
in the delta and exists discontinuously
beneath the entire Mackenzie Lowlands
north of Great Slave Lake. Depending
on the type of vegetation cover, the
top few inches to several feet of
ground above the permafrost thaws
during the summer months. Northern
construction of airfields, roads,
and pipelines has to be adapted to
these permafrost conditions; houses
and other buildings are usually placed
on wooden piles that are sunk and
frozen into the permafrost for stability.
One of the distinctive features of
the town of Inuvik is a utilidor,
a linear boxlike metal container raised
slightly above the surface of the
ground, in which the separate sewer,
water, and heating pipes are placed.
Mackenzie River water-transport routes
terminate at Tuktoyaktuk on the Arctic
coast northeast of the delta; there
cargo is transferred to other vessels
of greater draft, which serve the
small settlements, radar stations,
and oil-exploration sites along the
western Arctic coast.
The Mackenzie Delta is a vast fan
of low-lying alluvial islands, covered
with black spruce, thinning northward.
These trees are large enough to be
used for construction of log buildings
and are widely used as fuel. The delta
is a maze of channels, cutoff lakes
and circular ponds, which are home
to a large muskrat population. The
delta is 80 km across, bordered by
the Richardson Mountains in the west
and the Caribou Hills in the east.
Below Point Separation the river splits
into 3 main, navigable channels: East
Channel, which flows past Inovik on
the easterly edge of the delta; Peel
Channel in the west, which flows past
Aklavik; and Middle Channel, which
carries the main outflow into the
Beaufort Sea. Tuktoyaktuk, northeast
of the delta, is the transfer point
for river and ocean cargo; its harbour
is open from July to late September.
[1]
You Tube video
We go for a flightseeing
tour with Ishmael Alunik over the
MacKenzie Delta and the Richardson
Mountains.
