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Wetland Classification and Mapping of the Kenai Lowland, Alaska
Map Unit Descriptions Ecosystem: Relict Glacial Drainageway Map Unit: DW35; DW53; DW3-5
Extent: DW35: 72 wetland polygons; 506.4 ha; 0.36% of wetland area; 0.44% of wetland polygons. DW53: 43 wetland polygons; 313.2 ha; 0.22% of wetland area; 0.26% of wetland polygons. DW3-5: 8 wetland polygons; 86.1 ha; 0.06% of wetland area; 0.05% of wetland polygons. |
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 A mixed DW35 unit in the City of Kenai (polygon 8438).
A segregated DW53 unit in the City of Kenai (polygon 8042).
A more or less segregated DW3-5 unit near Moose Point, along the Point Possession strip (polygon 6271). |
Wetland Indicators Type: Peat Average depth to water table: DW3: 32.1 cm; n=36 DW4: 53.3 cm; n=4 DW5: 37.4 cm; n=14 Organic layer thickness: DW3: 102.2 cm; n=40 DW4: 68.6 cm; n=4 DW5: 78.2 cm; n=14 Average depth to redoximorphic features: DW3: 67.8 cm; n=6 DW4: 70.0 cm at the single site measured DW5: 135.0 cm at the single site measured Common Soils: DW3: STARICHKOF, NIKOLAI, DOROSHIN, SLIKOK, COAL CREEK DW4: STARICHKOF, NIKOLAI DW5: NIKOLAI, STARICHKOF, TRUULI Common Plant communities: DW3 component: Sweetgale – Dwarf birch / Water horsetail Barclay's willow / Bluejoint / Marsh fivefinger Sweetgale – Shrubby cinquefoil DW4 component: DW5 component: Sphagnum moss - Ericaceous shrub Lutz spruce / Barclay's willow / Field horsetail / Crowberry |
| Accuracy
assessment: 15 polygons interpreted as DW35 on aerial photographs were
field checked. 3 remained DW35; 2 were revised to
DW55A; 1each was revised to: DW2,
DW2-5, DW3-5, DW4,
DW45A, DW5,
K2-4, K24, K34 and LB3. 11 polygons interpreted as DW53 on aerial photographs were field checked. 3 remained DW53; 1 each was revised to: DW3-5, DW3-5A, DW5, DW52, DW4, DW54, K34, LB36 and Rea. 4 polygons interpreted as DW3-5 on aerial photographs were field checked. 3 remained DW3-5; 1 was revised to LB63. |
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These wetlands are a complex of the shrubby hummocky DW3 Relict Glacial Drainageway component with a drier, DW5 unit, which is a thick sphagnum mat or an almost-forested component, where tree cover is less than 10 percent. These wetlands are encountered on narrower drainageways where either the two components segregate as parallel linear features, or mix on a scale too small to delineate. When a more or less pure bluejoint (Calamagrostis canadensis) component (DW4) is also present the unit is named DW3-5.
Where the components segregate, the hummocky shrubby component occupies a medial position in the drainageway, often bordering a wetter sedge-dominated or open water component towards the center of the drainageway. The drier sphagnum component borders the lateral upland, or a Discharge Slope ecosystem wetland. Where the components mix, two levels of microtopographic diversity are present: a few broad sphagnum hummocks in a matrix of smaller shrubby hummocks and standing water in microtopographic low spots. Typically the components are mixed when encountered along a modern 'underfit' stream, and segregated when found along relict features. Relict drainageway features like these are relatively common near the large relict lakebed complex north of the City of Kenai.
South of Clam Gulch, the DW5 component infrequently occurs as a Barclay's willow (Salix barclayi) plant community and not a spahgnum mat; its wetland status might only be met by the presence of shallow redoximorphic features.
