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Wetland Classification and Mapping of the Kenai Lowland, Alaska
Map Unit Descriptions Ecosystem: Depression Map Unit: D12; D21
Extent: D12: 28 wetland polygons; 227.5 ha; 0.16% of wetland area; 0.17% of wetland polygons. D21: 25 wetland polygons; 34.2 ha; 0.02% of wetland area; 0.15% of wetland polygons. |
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 A D12 depression east of Soldotna (polygon 647).
A D21 depression near Happy Valley, the D1 open water portion of this wetland is not show in the photograph (polygon 2370). |
Wetland Indicators Type: Peat Average depth to water table: D1 is open water; D2: 6.8 cm; n=5 Organic layer thickness: D1 is open water; D2: 146.2 cm; n=5 Average depth to redoximorphic features: D1 is open water; D2: n/a Common Soils: D1: pond D2: STARICHKOF and DOROSHIN Common Plant communities: D1 component: Sphagnum moss - Creeping sedge D2 component: Tall cottongrass - Livid sedge Beaked sedge – Water horsetail
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| Accuracy assessment: 3 polygons interpreted as D12 on aerial photographs were field checked. 1 remained D12, 2 were revised to D1-3. 2 polygons interpreted as D21 on aerial photographs were field checked. 1 remained D21, the other was revised to upland. | |
D12 and D21 units are typically small, and relatively uncommon. They are dominated by open water (D1) and, typically, sedge-dominated plant communities (D2). If the former dominates then the unit is named D12, and if sedges dominate, D21. These units may be found as segregated components with sedges ringing a central pool, or mixed, with sedges on micro-topographic high spots and standing water puddles in low spots. Two shrubs, sweetgale (Myrica gale) and dwarf birch (Betula nana) are also tolerant of a high water table, and are frequently associated with the sedges. Depressions are surrounded by upland and most commonly found on younger glacial surfaces, such as the moraine between Nikiski and Sterling, and also east of Sterling.
