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Wetland Classification and Mapping
of Seward, Alaska
Map Unit Descriptions Ecosystem: Headwater Fen Map Unit: H42
Seward Area Extent: 1 wetland polygon; 1.8 acres |
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The only H42 fen; on the glacier-cut bedrock bench above Fourth of July Creek. Tall cottongrass, a good indicators of a near-surface water table, occupies most of the foreground in the photo. The woodland and forested edge of the fen is the H4 component.
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Wetland Indicators Type: Peat with mineral soil fringe Average depth to water table: 10 cm Organic layer thickness: 146 cm in the peat Average depth to redoximorphic features: 20 cm in the mineral soil Common Soils: Peat: Typic Cryosaprists, Typic Cryohemists; Mineral Soil: Typic Cryaquents Plant communities: H2: Sphagnum - Tall cottongrass (Eriophorum angustifolium) H4: Mountain hemlock / early blueberry (Tsuga mertensiana / Vaccinium ovalifolium)
NWI: PEM1Bg (H2); PFO4Eg (H4) HGM: Terrene Basin groundwater-dominated Throughflow headwater. |
The single H42 wetland mapped in the Seward Area is a small fen with a center peatland dominated by tall cottongrass with some fewflower sedge and a few small open water pools. A forest of mountain hemlock with an early blueberry and crowberry understory rings the open fen and borders a first-order stream running through it.
Headwater Fen Ecosystem wetlands are sloping peatland fens at or near the headwaters of first-order streams. Seward area Headwater Fens are mapped only on the 800' elevation glacier-cut bedrock bench above Fourth of July Creek.
