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2019 Wetland Delineation Report <br /> Tucson South Sand and Gravel Mine—Brighton, Colorado <br /> The U.S. Geological Survey (USGS) produces the National Hydrography Dataset (NHD) that <br /> identifies perennial and intermittent streams, ponds, and lakes. The online database NHD Viewer <br /> tool (USGS 2015a) was queried for the Project area. The query found one NHD feature, South <br /> Platte River, in the project area. NHD data in the Project area are depicted in Attachment 1, Figure <br /> 1. <br /> The U.S. Department of Agriculture (USDA) Natural Resources Conservation Service (NRCS) is <br /> the source for hydric soils information. These data are available online via the Web Soil Survey <br /> tool (USDA-NRCS 2015). Data were obtained for the Project area and were used to cross-check <br /> against field sites that were initially observed to exhibit wetland or surface water conditions. Hydric <br /> soils were identified in the Project area associated with NWI and NHD mapped features. <br /> Additionally, the Web Soil Survey was queried for drainage class across the Project area. One <br /> soil, Nunn-Kim complex is listed by the NRCS as a hydric soil. <br /> The USDA-Farm Service Bureau (2016) produces current high-quality aerial photography through <br /> the National Agricultural Imagery Program (NAIP). This aerial photography was used to further <br /> refine the field delineation for wetlands and other surface waterbodies within the Project area. <br /> 2.2 Wetlands and Other Waters of the U.S. Desktop Results <br /> The Desktop Analysis identified locations where the proposed Project intersected possible <br /> wetlands or other WOTUS features. Remote sensing data (NWI, NHD, NRCS) are typically not <br /> precise. Tetra Tech wetland scientists determined that a field reconnaissance was required to <br /> determine the accurate locations and boundaries of wetlands and other WOTUS located in the <br /> Project area. <br /> 2.2.1 Floodplains <br /> The FEMA mapped floodplain of the South Platte River is intersected by the Project. Several <br /> forested, shrub, and palustrine emergent wetlands and canals with perennial or intermittent flow <br /> were mapped in the Project area as part of wetland delineation activities (Attachment 1, Figure <br /> 1.) <br /> 3. Wetland and Other WOTUS Delineation <br /> Methods and Results <br /> Wetland delineations for the Project were performed on July 6 and 7, 2017. The delineations were <br /> conducted in areas initially identified during the desktop analysis. Due to layout changes since <br /> delineations were completed, the northern parcel of the Project was not included as part of the <br /> 3 <br />