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Wetland Classification and Mapping of the Kenai Lowland, Alaska
Map Unit Descriptions Ecosystem: Relict Glacial Drainageway Map Units: DW45A; DW45; DW4-5A; DW54; DW5A4
Extent: DW45A: 10 wetland polygons; 74.4 ha; 0.05% of wetland area; 0.05% of wetland polygons. DW45: 5 wetland polygons; 32.3 ha; 0.02% of wetland area; 0.03% of wetland polygons. DW4-5A: 4 wetland polygons; 25.2 ha; 0.02% of wetland area; 0.02% of wetland polygons. DW54: 3 wetland polygons; 86.7 ha; 0.02% of wetlands area; 0.02% of wetland polygons. DW5A4: 2 wetland polygons; 2.6 ha; 0.00% of wetland area; 0.01% of wetland polygons. |
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A DW45A unit at the edge of the Tustumena 'Moosehorn' moraine near Kasilof (polygon 9202).
The single DW4-5A unit, at the edge of the Tustumena 'Moosehorn' moraine, near the Kasilof River at the outlet of Tustumena Lake. Areas of sphagnum moss with ericaceous shrubs, the DW5 component, not pictured (polygon 9813).
A DW54 unit near Marathon Road at the edge of the 1969 burn. A diverse, seral bluejoint meadow near a spruce and aspen woodland. Aspen is an upland indicator (polygon 8079). |
Wetland Indicators Data for DW45A, as DW5A4; DW4-5A are rare. Type: Peat, or mineral Average depth to water table: DW4: 53.3 cm; n=4 DW5: 37.4 cm; n=14 DW5A: 38.8 cm; n=24 Organic layer thickness: DW4: 68.6 cm; n=4 DW5: 78.2 cm; n=14 DW5A: 46.3 cm; n=24 Average depth to redoximorphic features: 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: DW4: STARICHKOF, NIKOLAI DW5: NIKOLAI, STARICHKOF, TRUULI DW5A: TRUULI, NIKOLAI, STARICHKOF, Common Plant communities: 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 |
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Accuracy assessment: The single polygon interpreted as
DW45A on aerial photographs that was field checked remained DW45A.
The single polygon interpreted as DW45 on aerial photographs that was field checked was revised to LB6. The 2 polygons interpreted as DW4-5A on aerial photographs that were field checked were revised to uplands. The single polygon interpreted as DW5A4 on aerial photographs that was field checked was revised to SM. None of the polygons interpreted as DW54 on aerial photographs were field checked. |
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DW45A complexes are dominated by bluejoint grass (Calamagrostis canadensis) but with a forested (usually Lutz spruce (Picea X lutzii)) component. When a deeper sphagnum peat or diverse Barclay's willow component (DW5) is also present the wetland is classified as DW4-5A. All of these are uncommon.
Microtopography is usually developed, with marsh fivefinger and standing water found in small micro-topographic low spots. DW45A is most frequently found along the margins of wetter drainageways or 'underfit' streams in the Ninilchik River watershed. Other DW45A units are in relatively dry areas at the head of larger relict glacial drainageway features.
Two of the DW54 units marginally meet the wetland criteria outlined in the 1987 Army Corps of Engineers Wetland Delineation Manual. One of these units is along Marathon road near the City of Kenai, and the other is on a high plateau in the headwaters of the Anchor River southeast of the village of Nikolaevsk. Both have a bluejoint component, but different DW5 components. The southern unit has an extensive diverse willow community; while the northern unit lies at the edge of the 1969 burn with a seral aspen and white spruce woodland margin, with diverse meadows. The fourth unit is near Stariski Creek.
None of the three widely scattered DW45 wetlands have been visited. They are considered to be a mixture of deeper peats and bluejoint-dominated components, perhaps with the bluejoint occupying wetter areas indicating subsurface flow, and a shrubby peatland occupying areas with a deeper, more stagnant water table.
Three of the four DW4-5A units are found along the edge of the 'Mooeshorn' moraine northwest of Tustumena Lake. The fourth is near the Kenai River, east of Soldotna.
