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Wetland Classification and Mapping of the Kenai Lowland, Alaska
Map Unit Descriptions
Ecosystem: Relict Glacial Drainageway Map Unit: DW1-5; DW1-4; DW1-5A
Extent: DW1-5: 9 wetland polygons; 86.8 ha; 0.06% of wetland area; 0.05% of wetland polygons. DW1-4: 8 wetland polygons; 242.9 ha; 0.17% of wetland area; 0.05% of wetland polygons. DW1-5A: 6 wetland polygons; 42.9 ha; 0.03% of wetland area; 0.04% of wetland polygons. |
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A segregated DW1-5 unit near Kasilof (polygon 9389).
A mixed DW1-5 unit near Mackey Lakes; east of Soldotna (polygon 850).
A segregated DW1-5A wetland near Ninilchik (polygon 2442).
A broad, segregated DW1-4 wetland along the terraced moraines north of Ninilchik (polygon 26042). |
Wetland Indicators Type: Peat, occasionally with mineral soil at the margins Average depth to water table: DW1: n/a DW2: 14.9 cm; n=25 DW3: 32.1 cm; n=36 DW4: 53.3 cm; n=4 DW5: 37.4 cm; n=14 DW5A: 38.8 cm; n=24 Organic layer thickness: DW1: n/a DW2: 132.2 cm; n=25 DW3: 102.2 cm; n=40 DW4: 68.6 cm; n=4 DW5: 78.2 cm; n=14 DW5A: 46.3 cm; n=24 Average depth to redoximorphic features: DW1: n/a DW2: 97.0 cm at the single site measured DW3: 67.8 cm; n=6 DW4: 70.0 cm at the single site measured DW5: 135.0 cm at the single site measured DW5A: 60.7 cm; n=3 Common Soils: DW1: n/a DW2: SALAMATOF, STARICHKOF DW3: STARICHKOF, NIKOLAI, DOROSHIN, SLIKOK, COAL CREEK DW4: STARICHKOF, NIKOLAI DW5: NIKOLAI, STARICHKOF, TRUULI DW5A: TRUULI, NIKOLAI, STARICHKOF, Common Plant communities: DW1 component: Tall cottongrass – Livid sedge Water sedge / Marsh fivefinger Beaked sedge – Water horsetail Sphagnum moss - Creeping sedge
DW2 component: Water sedge / Marsh fivefinger Sphagnum moss - Creeping sedge
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 DW5A component: Lutz spruce / Barclay's willow / Field horsetail / Crowberry |
| Accuracy assessment: 3 polygons interpreted as DW1-5 on aerial photographs were field checked. 2 remained DW1-5; 1 was revised to Rea. 3 polygons interpreted as DW1-5A on aerial photographs were field checked. One remained DW1-5A, 1 each was revised to DW1-3 and LB32. The single polygon interpreted as DW1-4 on aerial photographs that was field checked remained DW1-4. | |
These consecutive complexes are uncommon map units consisting of nearly all the Relict Glacial Drainageway components. If all of the Relict Glacial Drainageway components occur together, the unit is named DW1-5A; DW1-5 only lacks the woodland or forest component (DW5A), and DW1-4 lacks both the drier sphagnum / shrub plant community with a deeper water table (DW5), and the forest or woodland (DW5A) component.
These units are found on narrower drainageways, often where a parallel series of components including standing water with emergent vegetation (DW1); sedges with a shallow water table (DW2); hummocky shrubs (DW3); and Bluejoint grass (DW4, Calamagrostis canadensis) all occur (DW1-4). When sphagnum / shrub plant communities also occur, the unit is named DW1-5; and with a forest or woodland, DW1-5A.
The components can be intermixed or segregated in roughly parallel bands. Typically they are mixed when this unit is encountered along a modern 'underfit' stream, and segregated when found along ancient, abandoned features. Abandoned drainageway features are relatively common near the large relict lakebed complex north of the City of Kenai and on terrace treads of the moraines fronting the west slope of the Caribou Hills.
