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Wetland Classification and Mapping of the Kenai Lowland, Alaska
Map Unit Descriptions Ecosystem: Relict Glacial Drainageway Map Unit: DW21; DW12
Extent: DW21: 51 wetland polygons; 761.1 ha; 0.54% of wetland area; 0.31% of wetland polygons. DW12: 15 wetland polygons; 181.3 ha; 0.13% of wetland area; 0.09% of wetland polygons. |
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 A segrgated DW21 unit north of Kenai, near Salamatof Lake (polygon 1941).
A mixed DW21 unit in a large peatland complex east of the City of Kenai (polygon 8222). |
Wetland Indicators Type: Peat Average depth to water table: DW1: n/a DW2: 14.9 cm; n=25 Organic layer thickness: DW1: n/a DW2: 132.2 cm; n=25 Average depth to redoximorphic features: DW1: n/a DW2: 97.0 cm at the single site measured Common Soils: DW1: n/a DW2: SALAMATOF, 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 |
| Accuracy assessment: 6 polygons interpreted as DW21 on aerial photographs were field checked. 3 remained DW21, 1 each was revised to: DW1-3, DW32 and LB32. 3 polygons interpreted as DW12 on aerial photographs were field checked. None remained DW12; one each was revised to: DW1-3, DW21 and DW2. | |
DW12 and DW21 map units are widespread, especially along the terraced moraines at the western edge of the Caribou Hills and connecting the large Kettles that occur between Sterling and Nikiski. They occupy wetter, central zones of Relict Glacial Drainageway ecosystems. Flowing surface water with emergent vegetation (DW1) is present alongside areas with the water table just below the surface, where sedges often dominate (DW2). Typically the two components, DW1 and DW2, segregate, with a linear surface water feature (DW1) bordered by parallel sedge-dominated wetlands (DW2). DW12 is assigned to wetlands where more flowing water is present; where higher sedge cover is present DW21 is assigned.
These units are frequently located just upstream from Riparian ecosystems on landscapes where peatlands occupy ancient glacial rivers. Although the water is often flowing through the center of these units, the bed and bank morphology which characterizes a Riparian Ecosystem is absent. Sometimes slopes are gentle enough so that a string of pools form perpendicular to flow along a broadly linear feature.
