2019-05-14_PERMIT FILE - M2019025 (16)

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ATTACHMENT D 1 .0 INTRODUCTION Coulson Excavating Company is developing plans to construct a sand and gravel pit known as the Aggregate Resource on two parcels located northeast of the intersection of Weld County Roads 54 and 13. The project site is located southeast of Johnstown, along the Big Thompson River in Section 19 of Township 5 North and Range 76 in Weld County, Colorado (Figure 1). The western parcel owned by Coulson Excavating measures approximately 117.6 acres and the eastern parcel owned by Croissant Family Farm measures 69.5 acres. To aid in project planning and the special use review,wetlands were delineated within seven proposed mining areas encompassing approximately 95.7 acres (Figure 2). A total of 1.06 acres of wetlands were identified during the delineation in May 2018 (Figure 3;Table 1). The U.S. Fish &Wildlife Service has identified wetlands in Larimer County as potential habitat for two federally listed plants: the Ute ladies' tresses orchid (Spiranthes diluvialis) and the Colorado butterfly plant (Laura neomexicana ssp. neomexicona). To evaluate whether the project site is potential habitat for these two rare plants, a habitat assessment was completed during field reconnaissance in May 2018. This report describes the wetland and upland habitats present on the project site and assesses their suitability to support the Ute ladies' tresses orchid and Colorado butterfly plant. It describes the wetlands in terms of their geomorphic setting, vegetation, hydrology, and ecological condition, and discusses whether they are potentially suitable habitat. Please note, all Figures are in Section 8.0, Tables are in Section 9.0, and Photographs are in Section 10.0. 2.0 ENVIRONMENTAL SETTING As described above, the wetland delineation was conducted for seven proposed mining areas at the Aggregate Resource that cover a total of approximately 95.7 acres. These mining areas are located on the historic floodplain of the Big Thompson River on both the left and right sides. The 2013 flood event impacted the Big Thompson River through the project site, leaving large cobble and sand deposits along the river corridor which are visible on the aerial photograph (Photo 1; Figure 2). As shown by the wetland map (Figure 3), several oxbow wetlands were identified on the historic floodplain of the river within the proposed mining areas (Figure 3). The project site has had an agricultural land use history. The pastures south and east of the Big Thompson River are grazed by cattle, but the areas on the north side did not show evidence of recent grazing. The Hill and Brush Ditch, a diversion from the Big Thompson River, is located just north of the proposed mining areas (Photo 2). A wetland-lined lateral ditch was flowing south from the Hill and Brush Ditch through the proposed mining area to the Big Thompson River at the time of the delineation in May 2018 (Photo 3). The water appeared to be the result of recent heavy rainfall in the area that had collected in the Hill & Brush ditch, since it was not flowing at the time and only had pooled water in the area of the diversion structure. Smaller irrigation laterals east of the return flow ditch were in disrepair and appear to have been abandoned. There are two active oil and gas wells on the Croissant Family Farm parcel, and two unused oil and gas wells and a plugged and abandoned oil well are located on the Coulson parcel (Figure 2). 1