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Wetland Classification and Mapping
of the Kenai Lowland, Alaska
Map Unit Descriptions Ecosystem: Depression Map Unit: D34; D43; D43d
Extent: D34: 247 wetland polygons; 445.0 ha; 0.31% of wetland area; 1.50% of wetland polygons. D43: 159 wetland polygons; 323.4 ha; 0.23% of wetland area; 0.96% of wetland polygons. D43d: 1 wetland polygon; 3.6 ha; 0.00% of wetland area, 0.01% of wetland polygons. |
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 A D34 depression near the coast, N of Nikiski (polygon 1196).
A D43 depression northeast of Daniel's Lake, north of Nikiski (polygon 1286). |
Wetland Indicators Type: Peat and mineral soil. Average depth to water table: D3: 10.0 cm n=1 D4: 55.5 cm; n=11 Organic layer thickness: D3: 121.0; n=3 D4: 85.8 cm; n=17 Average depth to redoximorphic features: D3: n/a D4: 24.3 cm; n=3 Common Soils: D4: STARICHKOF, TRUULI, SPENARD, NIKOLAI Common Plant communities: D3 component: D4 component: Black spruce / Woodland horsetail - Labrador tea |
| Accuracy assessment: 27 polygons interpreted as D34 on aerial photographs were field checked. 14 remained D34, 1 each was revised to D4, D43 and DISTURB; 2 were revised to D2-4 and 8 were revised to upland. 18 polygons interpreted on aerial photographs to be D43 were field checked. 14 remained D43, 1 was revised to D2-4 and 4 were revised to upland. | |
D34 and D43 units are widespread throughout the project area, especially on late Wisconsin-aged moraines. They occur in Depression Ecosystems with a deeper water table, adjacent to uplands. Typically these polygons consist of either a mixed combination of shrub or bluejoint dominated openings (D3 component) amongst forest patches (D4 component), or segregated components arranged as concentric rings, with a shrubby center (D3) grading to a forested margin (D4).
D3 components are typically peatlands dominated by shrubs, and are found between forested margins (D4) of a depression, and the wetter components typically dominated by sedges (D2). This is also the zone where bluejoint grass (Calamagrostis canadensis) or a sphagnum lawn dominates some depressions.
D4 components are usually dominated by woodlands, with a deeper water table. This is the component where wetlands grade to uplands. Often mineral soils are found here, and the only wetland indicator is a soil horizon containing redoximorphic features close to the surface.
In Homer, the single polygon mapped as D43d refers to a D43 wetland that is now disturbed.
