<strong>Botany</strong> <strong>and</strong> Wetl<strong>and</strong>s <strong>Study</strong> <strong>Report</strong>Southeast Alaska Power AgencyFigure 4. Wetl<strong>and</strong>s in the Analysis AreaSwan Lake Hydroelectric Project January 2013FERC Project No. 2911 Page 15 Version: Agency Review
<strong>Botany</strong> <strong>and</strong> Wetl<strong>and</strong>s <strong>Study</strong> <strong>Report</strong>Southeast Alaska Power Agency3.7.1 Forested Wetl<strong>and</strong>sForested wetl<strong>and</strong>s occur on poorly or very poorly drained hydric mineral <strong>and</strong> organic soils.Forested wetl<strong>and</strong>s are most common on broad glacial valley bottoms, gently sloping hill slopesor benches, but are also commonly found on steep terrain in areas overlaying volcanic geology.These wetl<strong>and</strong>s provide important functions including wildlife habitat, water qualityimprovement, peak flow reduction <strong>and</strong> erosion control, organic matter production <strong>and</strong> export,<strong>and</strong> nutrient <strong>and</strong> carbon cycling (Cooke 2005). Forested wetl<strong>and</strong>s may support the transfer ofwater to downslope resources, function as recharge areas for groundwater <strong>and</strong> streams, <strong>and</strong>provide depositional areas for sediment <strong>and</strong> nutrients.Forested wetl<strong>and</strong>s are wetl<strong>and</strong>s dominated by vegetation greater than 20 feet in height. Theoverstory in forested wetl<strong>and</strong>s in the analysis area is varied but typically consists of westernhemlock, western red cedar (Thuja plicata), Alaska yellow cedar, <strong>and</strong> red alder. The understory isoften dominated by skunk cabbage (Lysichitum americanum). Other shrub <strong>and</strong> herbaceousspecies occurring in the understory of forested wetl<strong>and</strong>s in the analysis area include seepmonkeyflower (Mimulus guttatus), deer cabbage (Nephrophyllidium crista‐galli), fowlmannagrass (Glyceria elata [G. striata]), California black currant (Ribes bracteosum), <strong>and</strong>salmonberry. In the analysis area, approximately 60.9 acres (43.4 percent) consists of forestedwetl<strong>and</strong>s.3.7.2 Emergent Sedge Wetl<strong>and</strong>sEmergent wetl<strong>and</strong>s contain organic soils that are very poorly drained, moderately deep, <strong>and</strong> aredominated by sedges <strong>and</strong> grasses. They may include poor fens <strong>and</strong> rich bogs <strong>and</strong> there istypically some water flow through. Vegetation in these wetl<strong>and</strong>s typically consist primarily ofvarious sedges <strong>and</strong> mosses with scattered shrubs. In the analysis area, emergent wetl<strong>and</strong>s weretypically found along the margin of Swan Lake adjacent to open water. Species commonlyobserved in emergent wetl<strong>and</strong>s in the analysis area include Sitka sedge (Carex aquatilis),smoothstem sedge (Carex laeviculmis), bluejoint reedgrass (Calamagrostis canadensis), marshcinquefoil (Comarum palustre [Potentilla palustris]), western water hemlock (Cicuta douglasii),scattered willows (Salix sp.), <strong>and</strong> occasionally small‐fruited bulrush (Scirpus microcarpus). Thesewetl<strong>and</strong>s provide habitat for unique plants <strong>and</strong> animals, <strong>and</strong> contribute water to downsloperesources, provide carbon <strong>and</strong> nutrient cycling benefits for watershed function, <strong>and</strong> providewater storage for flood <strong>and</strong> erosion control (EPA 2011). In the analysis area, approximately 15acres (10.7 percent) consists of emergent wetl<strong>and</strong>s. Emergent wetl<strong>and</strong>s mapped in the analysisarea include types mapped as freshwater emergent sedge (emergent sedge/FW) <strong>and</strong> tall sedgefens. A few small emergent wetl<strong>and</strong>s were observed outside the analysis area along existingroads <strong>and</strong> near existing facilities associated with dam operations.3.7.3 Moss MuskegsMoss muskegs are characterized by nutrient limiting acid peat bogs, dominated by sphagnummoss <strong>and</strong> peat deposits. Muskeg wetl<strong>and</strong>s support a distinctive flora which are adapted to life inSwan Lake Hydroelectric Project January 2013FERC Project No. 2911 Page 16 Version: Agency Review
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