Botany and Wetlands Study Report - McMillen, LLC

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Botany and Wetlands Study ReportSoutheast Alaska Power Agency2.3 Field Investigation SurveysField surveys for botanical and wetland resources were conducted in the analysis area fromAugust 6‐10, 2012. Field surveys included the shoreline of Swan Lake and along the banks of LostCreek up to the 350‐foot elevation level. Surveys were dispersed throughout the analysis area ina variety of habitat types, elevations and aspects. The surveys were done primarily by boatbecause steep terrain and dense vegetation restricted the ability to survey the majority of theshoreline on foot (see Appendix C, Swan Lake Project Area Photos). The boat traveled close tothe shore and binoculars were used to search the shore. At the time of the survey, the waterlevel was at its current maximum height of 330 feet, giving surveyors an optimal view. Botanistsand ecologists walked the shoreline and creek margins in the limited areas where slope andvegetation density allowed.2.3.1 Sensitive and Rare PlantsFocused intuitive controlled surveys for sensitive and rare plants were conducted within theanalysis area (see Appendix D for a general description of botanical survey types). This surveytype involves identifying suitable habitat for targeted species and then focusing the survey effortwithin those identified habitats. The field surveys were conducted from August 6 to 10, 2012, anappropriate time of year to identify targeted species.No populations of sensitive plant species were identified in the analysis area during field surveys.Populations of two rare plant species were identified and mapped as a result of field surveys forthis project. Additionally, two plant species not included on the 2012 AKNHP Rare Vascular PlantList but considered species of interest for the Tongass National Forest were observed in theanalysis area (see Section 3.3). Based on field surveys, the location of each population wasmapped and digitized and a plant count or estimate was made for each. Plant Survey Field formsand a spreadsheet identifying all plant species observed in the analysis area were also preparedand are included in the project record. Additionally, Region 10 (R10) Threatened and EndangeredSpecies (TES) Plant Element Occurrence field forms were completed according to protocol forthe Alaska Region for rare plants in the analysis area and are included in Appendix E.2.3.2 Wetland ResourcesSeveral wetland types were observed during field surveys. These include forested wetlands,emergent wetlands, and moss muskegs (Appendix C, Swan Lake Project Area Photos). Wetlandresources were mapped, to the extent possible, using a Trimble GeoXH global positioning systemunit (GPS). Wetlands that could not be mapped using GPS were hand‐delineated on aerial mapsusing the Tongass NF wetland layers and hydric soils layers from the Ketchikan area soil surveyfor the Tongass NF to help refine the boundaries.Swan Lake Hydroelectric Project January 2013FERC Project No. 2911 Page 7 Version: Agency Review
Botany and Wetlands Study ReportSoutheast Alaska Power Agency3 ENVIRONMENTAL SETTINGThe Tongass National Forest, including Revillagigedo Island, is dominated by temperaterainforest. The maritime climate is characterized by cool, wet summers and mild winters withsignificant precipitation as snow and rainfall. In Ketchikan, approximately 23 miles southwest ofthe study area, typical summer temperatures average 60‐65° F, while winter temperaturesaverage 39‐44°F. The year‐round average temperature is 51.6° F. Annual precipitation as rainfallaverages 117 inches, with the least precipitation (16 percent) occurring from May through July.The wettest month is October with an average of more than 22 inches accumulation. Snowfallaccumulation averages 37 inches per year, with the most snow accumulating in January (35percent) (Western Regional Climate Center 2012). The study area lies about 300 to 350 feethigher in elevation than Ketchikan.Southeast Alaska is geologically composed of linear belts of tectonic assemblages that liesub‐parallel to, and have been accreted to, the continental margin. This coastal group ofmountainous islands lies west of the mainland coast range. This area has been subjected toisostatic and tectonic uplift, as well as glacial and other climatic weathering processes (ForestService 1996). Bedrock in the project area is made up of the Taku terrane and includes“metamorphosed marine shales and muddy sandstones, metamorphosed andesites, basalts, andrhyolite lavas, along with small amounts of limestone, marble, and conglomerate” (Connor andO’Haire 1988:10). Many of the lakes, valleys, and mountains in and around the project area arethe result of more recent glaciation.3.1 Vegetation ResourcesThe Swan Lake Expansion analysis area is located on the Ketchikan‐Misty Fiords Ranger Districton Revillagigedo Island in southeast Alaska, 22 miles northeast of Ketchikan. The TongassNational Forest, including Revillagigedo Island, is covered primarily by temperate rainforestconsisting of Sitka spruce (Picea sitchensis) and western hemlock (Tsuga heterophylla), withlesser amounts of mountain hemlock (Tsuga mertensiana), Alaska yellow cedar (Callitropsis[Chamaecyparis] nootkatensis), and lodgepole pine (Pinus contorta). Common understoryspecies include oval‐leaf blueberry (Vaccinium ovalifolium), Alaska blueberry, (Vacciniumalaskanse), Devil’s club (Oploplanax horridum), thimbleberry (Rubus parviflorus), salmonberry(Rubus spectabilis), twisted‐stalk (Streptopus spp.), queen’s cup (Clintonia uniflora), three‐leaffoamflower (Tiarella trifoliata), and lady fern (Athyrium filix‐femina).Red alder (Alnus rubra) and Sitka alder (Alnus viridis ssp. sinuata) occupy riparian areas andother sites, such as avalanche chutes, where bare mineral soils are exposed. On RevillagigedoIsland, extensive forest areas have been logged. Plant communities in these areas have changedto early successional types that differ in character than old growth forests. Regeneration is rapidand most of the logged areas are covered by dense stands of young growth.Swan Lake Hydroelectric Project January 2013FERC Project No. 2911 Page 8 Version: Agency Review
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