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COR Wetland Mitigation Memorandum October 7, 2021 Page 6 Wetland Delineation Results— Northwest Wetland The northwest mitigation site is comprised of a large wetland on the north side with a single stormwater treatment basin located on the south side of the site. Upland buffer is present around the perimeter of the wetland. A berm separates the storm water pond from the wetland and is considered part of the upland buffer component. The wetland is dominated by hybrid cattail (Typha glauca), which is present throughout the wetland. The exception being a larger area of deep marsh in the center of the basin which lacks vegetation. Along the perimeter there is minimal transition to upland, and the wetland is present essentially at the toe of the slope. While not dominant overall, small pockets of sedges are present, which are likely remnants from the 2011 restoration efforts. A few small black willow (Salix nigra)trees have also become established within the margins of the wetland. The stormwater pond components of the site are almost entirely composed of hybrid cattail and open water. Upland buffer lies around the perimeter of the site. While reed canary grass is present at the base of the upland buffer the mixture of vegetation is more diverse than expected. Areas of spotted knapweed (Centaurea stoebe) and smooth brome (Bromus inermis) are present, but smaller density native species such as little bluestem (Schizachyrium scoparium), big bluestem (Andropogon gerardii), and sideoats grama (Bouteloua curtipendula)are also present. Overall, the upland buffer is diverse, but is not dominated by native species. Like the wetlands, native upland vegetation includes some remnants of the 2011 reseeding. The berm between the wetland and storm water treatment area is entirely reed canary grass, and much of it may be wetland, or at least wet enough to discourage upland species from being present. Table 6 is a summary of the vegetation observed in the wetland and upland buffer portions of the Northwest mitigation site. Table 6: Northwest Mitigation Site Vegetation Summary Wetland Plant Inventory Upland Buffer Plant Inventory Scientific Name Common Name Scientific Name Common Name Acorus calamus Sweetflag Andropogon gerardii Big bluestem Asclepias incarnata Swamp milkweed Asclepias syriaca Common milkweed Carex stricta Tussock sedge Berteroa incana Hoary alyssum Hydrophyllum virginianum Shawnee-salad Bouteloua curtipendula Sideoats grams Onoclea sensibilis Sensitive fern Bromus inermis Smooth brome grass Phalaris arundinacea Reed canary Centaurea stoebe Spotted knapweed grass Phragmites australis Giant reed grass Monarda fistulosa Wild bergamot Poa palustris Fowl bluegrass Oenothera biennis Evening primrose Rumex crispus Curly dock Panicum virgatum Switchgrass Salix nigra Black willow Pycnanthemum Mountain mint vir inianum Scirpus cyperinus Woolgrass Salix nigra Black willow Typha glauca Hybrid cattail Schizachyrium scoparium Little bluestem FUrtica dioca Stinging nettle Solidago canadensis Canada goldenrod Solidago rigida Stiff goldenrod Ulmus pumila Siberian elm Verbascum thapsus Common mullein