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City of Everett Public Works Department | September 26, 2024 Page 3 <br /> File No. 00661-128-03 <br />Vegetation Transect data will be primarily used to address AMS PSs: 1-3, 1-4, 1-5 and 1-6. <br />Wetland Sample Plots and Habitat Mapping Ground Truthing <br />To delineate and map areas of wetland habitat in the AMS we will use a combination of aerial imagery and <br />Light Detection and Ranging (lidar) elevations captured with a drone (Task 200), and wetland determination <br />sample plot data collected during the vegetation transect monitoring effort. <br />The area of estuarine wetland habitat within the site will be identified based on the elevation of Mean <br />Higher High Water (MHHW) as the USACE limit of jurisdiction for tidal areas. The occurrence of hydrology <br />will be verified by reviewing the georeferenced high tide aerial imagery and corresponding tidal chart. The <br />occurrence of hydric soils and salt-tolerant hydrophytic vegetation and/or mudflat will be field verified with <br />wetland determination sample plot data based on routine-level wetland delineation methods using the <br />1987 Corps of Engineers Wetland Delineation Manual (Environmental Laboratory 19872) as updated by <br />the Regional Supplement to the Corps of Engineers Wetland Delineation Manual: Western Mountains, <br />Valleys, and Coast Region (USACE 2010 3) and the Ecology’s Washington State Wetlands Identification and <br />Delineation Manual (Ecology 1997 4). <br />The number of wetland determination sample plots will be identified in the field based on results of the <br />Year 5 wetland delineation and observed site conditions. <br />Wetland sample plots will be primarily used to address AMS PSs: 1-1 and 1-2. <br />Spot Identification and Distribution of Cattails (Typha sp.) <br />While traversing the site for vegetation transect monitoring and wetland sample plots, instances of cattail <br />species (Typha sp.) will be visually assessed for general patch density and species composition. As <br />described in the May 30, 2024, Performance Standard 1-5 Memorandum5, assessment of cattail <br />distribution across the AMS will be accomplished through assessment of aerial imagery combined with <br />vegetation transect data. During the field data collection, cattail patches as depicted in Figures 5A and 5B <br />of the memorandum will be visually assessed for species density and composition, either through formal <br />vegetation transect quadrates (when the two coincide based on random transect placement method), or a <br />patch scale visual assessment for patches without transect data. Field species ID and patch species <br />composition data will be used to inform the drone aerial imagery analysis for cattail patch contraction and <br />expansion. <br />Cattail Identification and Distribution will be primarily used to address AMS PS: 1-5. <br /> <br />2 Environmental Laboratory. 1987. Corps of Engineers Wetlands Delineation Manual. Technical Report Y-87-1, U.S. Army Engineer Waterways <br />Experiment Station, Vicksburg, Mississippi. <br />3 United States Army Corps of Engineers (USACE), 2010, Regional Supplement to the Corps of Engineers Wetland Delineation Manual: <br />Western Mountains, Valleys, and Coast Region, ed. J.S. Wakeley, R. W. Lichvar, and C.V. Noble. ERDC/EL TR-10-3. Vicksburg, MS: <br />U.S. Army Engineer Research and Development Center. <br />4 Washington State Department of Ecology (Ecology). 1997. Washington State Wetlands Identification and Delineation Manual. Ecology <br /> Publication #96-94. March 1997. <br />5 GeoEngineers Inc.. 2024. Memorandum to Heather Griffin. Diking Improvement District No. 5 Smith Island Estuary Restoration Advance Mitigation <br /> Site – Performance Standard 1-5 Cattail Management, Everett, Washington. GEI File No. 0661-128-02. May 30, 2024.