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Wetland Classification and Mapping of the Kenai Lowland, Alaska
Map Unit Descriptions Ecosystem: Relict Glacial Lakebed
Map Unit: LB24; LB42; LB2-4
Extent: LB24: 124 wetland polygons; 1408.8 ha; 0.99% of wetland area; 0.64% of wetland polygons. LB42: 78 wetland polygons; 839.6 ha; 0.59% of wetland area; 0.47% of wetland polygons. LB2-4: 86 wetland polygons; 1664.0 ha; 1.17% of wetland area; 0.52% of wetland polygons. |
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 An LB24 unit southeast of Ninilchik (polygon 2399).
An LB42 wetland in the City of Kenai (polygon 8599).
A segregated LB2-4 wetland southeast of Ninilchik (polygon 2478). |
Wetland Indicators Data below for LB24 and LB42; no data for LB2-4 Type: Peat Average depth to water table: LB2: 11.3 cm; n=32 LB3: 9.9 cm; n=13 LB4: 19.5 cm; n=50 Organic layer thickness: LB2: 146.6 cm; n=36 LB3: 119.2 cm; n=13 LB4: 116.0 cm; n=52 Average depth to redoximorphic features: LB2: n/a LB3: n/a LB4: 79.0 cm; n=3 Common Soils: LB2: STARICHKOF, DOROSHIN LB3: STARICHKOF, DOROSHIN LB4: STARICHKOF, DOROSHIN, SALAMATOF, NIKOLAI Common Plant communities: LB2 component: Tufted bulrush - Tall cottongrass Sweetgale – Dwarf birch / Water horsetail Tufted bulrush – Fewflower sedge
LB3 component: Sphagnum moss - Ericaceous shrub Sphagnum moss / Tall cottongrass Sphagnum moss - Manyflower sedge Tufted bulrush – Fewflower sedge Fewflower sedge – Tall cottongrass LB4 component: Sweetgale - Shrubby cinquefoil Sphagnum moss - Ericaceous shrub |
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Accuracy assessment: 28 polygons interpreted as LB24 on
aerial photographs were field checked. 11 remained K3; 8 were revised
toLB2-4; 2 each were revised to LB23 and LB2-4; 1
each was revised to: DW23, DW32,
LB34, LB43 and
SSC. 20 polygons interpreted as LB42 on aerial photographs were field checked. 9 remained LB42. 4 were revised to LB24; 3 were revised to LB2-4; 1 each was revised to D1-3, DW23, LB2 and LB4. 17 polygons interpreted as LB2-4 on aerial photographs were field checked. 12 remained LB2-4; 2 were revised to LB24; 1 each was revised to LB3, LB32 and LB34. |
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The LB2-4 complexes are peatlands which include a shallow water table sedge-dominated component (LB2) with the deeper water table, a sphagnum moss lawn component (LB3), and a shrub dominated component (LB4). All three of these wetlands occupy extensive relict glacial lake bottoms, usually near the coastal margin of the lowlands. They indicate patterned fen development: Micro-highs, occupied by sphagnum lawns (LB3) and / or shrubs (LB4), often form low strangs (ridges) above ill-defined, elongate micro-lows (flarks) occupied by sedge communities (LB2). When the sphagnum lawn is absent, and sedges and a shallower water table predominate, the wetland is named LB24; when shrub communities dominate it is named LB42, when a sphagnum lawn is present the wetland is named LB2-4.
Wetlands with a spahgnum lawn (LB2-4) usually contain more developed strang-flark morphology, with higher ridges, and more extensive flarks. They are approaching fully developed patterned fens, only lacking open water pools (LB1) and spruce-topped (Picea spp.) strangs and tree island components (LB6).
