Map Unit Descriptions
Geomorphic Component: Discharge Slope
Hydrologic Component: SA
Extent: 63 wetland polygons; 282.9 ha; 0.20% of wetland area; 0.38% of wetland polygons.
 A wetland mapped as SA adjacent to Bridge Access Road, in the City of Kenai (polygon 8479). |
Wetland Indicators Type: Mineral or Peat Average depth to water table: Organic layer thickness: 105.3 cm; n=6 Average depth to redoximorphic features: 30.8 cm; n=4 Common Soils: STARICHKOF, SPENARD, NIKOLAI, BELUGA Common Plant communities:
NWI: PSS1Bn,g HGM: Terrene Slope groundwater-dominated Throughflow |
Accuracy assessment: 7 polygons interpreted as SA on aerial photographs were field checked. 5 remained SA; 1 was revised to SMA; 1 was revised to SCS. |
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Wetlands mapped as SA are toeslopes dominated by alder, usually thinleaf alder (Alnus incana ssp tenuifolia). This wetland type is uncommonly mapped on its own, and has been found only near tidewater wetlands, either along the Kenai or Kasilof Rivers; at the upper reaches of a lagoon north of Nikiski, that was a peatland before the 1964 earthquake; or at the base of the bluffs above Homer. Thinleaf alder typically occupies the wettest toeslope positions.
The component SA is more commonly mapped in complex with others, especially the Lutz spruce-dominated SL hydrologic component. These wetland polygons are designated SLA or SAL, depending on whether spruce or alder is dominant, respectively. A uniform spruce forest or woodland (greater than 10% spruce cover) with an alder understory is designated SL and is also common along wet toeslopes, especially on the glacial deposits of the Last Glacial Maximum found along the western edge of the Caribou Hills between Ninilchik and Anchor Point.
