Table 10 (cont'd).
Ecodistrict
Ecosubdistrict
Description
TananaWood
Clear Creek
A flat area dominated by abandoned floodplain cover deposits that have incorporated substantial
River Flats
Lowlands
amounts of lowland loess and organic deposits, as evident by the lack of fluvial patterning of the sur-
face. Flat bogs are prevalent, but collapse-scar bogs are uncommon. The area is hydrologically linked
to the Dry Creek Lowlands and has occasional seeps and small streams associated with subsurface
water originating from Dry Creek. Permafrost is nearly continuous and ice-wedge polygons are evi-
dent in a few places. Vegetation is dominated by shrub birchericaceous low scrub, wet willowsedge
fens, and black spruce and tamarack forests.
Willow Creek
An area dominated by thick (34 m) abandoned-floodplain cover deposits and floating fens. Discon-
Lowlands
tinuous, ice-rich permafrost is degrading rapidly and thermokarst features are abundant. Recently
abandoned river channels are common and appear to be related to changes in water movement from
surface streams to subsurface flow as floating fens increase in dominance. The area is a groundwater
discharge zone linked to the Wood River Lowlands. Common vegetation includes birch forests, shrub
swamps, floating fens, and collapse scar bogs, with occasional patches of black spruce forests and
shrub birchericaceous low scrub.
Crooked Creek
An area dominated by thin (0.32 m) abandoned-floodplain cover deposits and meandering abandoned
Lowlands
river channels. Collapse-scars bogs are abundant, as well as infilling old thaw lake basins. Floating
fens are uncommon. The area receives much less groundwater from the Wood River Lowlands than
does the Willow Creek Lowlands. Permafrost is discontinuous. Vegetation is dominated by black
spruce and birch forests, shrub swamps, and sedgemoss bogs.
Dry Creek
An area dominated by alluvial fan deposits associated with Dry Creek; also present are riverbed
Lowlands
deposits, cover deposits, and old dissected terraces associated with the Healy Glaciation. Dry Creek
looses its water as it traverses the fan and disappears before it reaches the flats. Permafrost is nearly
continuous. Vegetation is dominated by black spruce and birch forests, low and tall shrub (post-burn),
shrub swamps and sedgemoss bogs.
Wood River
An area dominated by thick (12 m), fine-grained cover deposits on a glacial outwash fan associated
Lowlands
with the Riley Creek Glaciation. Thermokarst features such as organic fens and bogs are common.
There is both substantial surface and groundwater flow. Small streams form a dense network of nearly
straight channels. Permafrost is discontinuous, but absent in bogs, fens and swamps. Vegetation is
dominated by black spruce and birch forests, shrub-tussock meadows, shrub swamps and sedgemoss
bogs.
TananaWood
Little Delta River
An area dominated by thick abandoned-floodplain cover deposits with few thermokarst features such
River Flats
Lowlands
as collapse scar bogs. There are occasional seeps and headwater streams. Permafrost is nearly continu-
ous and fine-grained soils are usually saturated. Vegetation is dominated by black spruce and shrub-
tussock meadows, with minor amounts of birch forest along well-drained uplands.
TananaBlair
The Wood River and Clear Creek Buttes and the hills near Blair Lakes are dominated by residual soils
Lake Uplands
on upper slopes, upland retransported deposits on midslopes, and lowland retransported deposits on
lower slopes. The units are hydrologically linked by surface and groundwater movement. Permafrost
is present on northern and lower slopes and absent on southern slopes. The vegetation is dominated
by white sprucebirchaspen forests on upper slopes, black spruce and birch forests on lower slopes,
and dry Elymus-shrub on steep south-facing bluffs.
Wood River
An area dominated by well-drained abandoned riverbed deposits associated with a glacial outwash
Uplands
fan of the Riley Creek Glaciation. Surface streams are uncommon. Permafrost probably is absent and
thermokarst features are not evident. The vegetation is dominated by white sprucebirchaspen forests
or by herbaceous and shrubby vegetation in burned areas.
SteeseWhite
ChenaSalcha
An association of weathered bedrock in alpine areas, residual soil on upper slopes, upland loess near
Mountains
Highlands
the Tanana River, upland retransported deposits, lowland retransported deposits on lower slopes, and
headwater streams. The areas are hydrologically linked by surface and groundwater flow. Permafrost
is present on northern and lower slopes and absent on southern slopes. White sprucebirchaspen forests
on south slopes, black spruce forests on north slopes, riverine willows in drainages, and alpine tundra
on high exposed ridges are common.
Little Chena
Well-drained upland areas that have a loess cap over weathered bedrock. Permafrost is present on
Uplands
northern and lower slopes and absent on southern slopes. In permafrost-free areas, groundwater is
found only at great depths, whereas in permafrost areas, the soil may be saturated for portions of the
growing season white sprucebirchaspen forests on south slopes, black spruce forests on north slopes,
and riverine willows in small drainages are common.
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