Laserfiche WebLink
Natural Resources Assessment <br />P125 Gravel Mine - Southwest of State Highway 66 and County Road 17 <br />Weld County, Colorado <br /> <br />ERO Project #24-180 9 <br />ERO Resources Corporation <br />soil indicator redox dark surface was met at DP1 and DP3. Hydrology indicators met included surface <br />water (DP1), a high water table (DP1), saturation (DP1), geomorphic position (DP1 and DP2), and a <br />successful FAC-neutral test (DP1 and DP2). <br />Uplands adjacent to W1 and W2 (DP2 and DP4) were dominated by plains cottonwood, western <br />wheatgrass, prickly Russian thistle (Salsola tragus), saltgrass (Distichlis spicata), and musk thistle <br />(Carduus nutans). Indicators of hydrophytic vegetation were not met at DP2 and DP4. Soil samples were <br />not taken at DP2 and DP4 due to the lack of indicators of hydrophytic vegetation and wetlands; <br />therefore, hydric soils were assumed absent. No primary or secondary hydrology indicators were <br />observed at DP2 or DP4. <br />Riverine Wetlands (W3 and W4) <br />W3 and W4 are in the northwestern portion of the project area in depressional swales that appear to be <br />oxbow channels of St. Vrain Creek (Figure 2; Photo 6 and Photo 7). W3 and W4 are not identified on the <br />NHD; however, W3 is identified as a palustrine unconsolidated bottom semipermanently flooded <br />wetland and W4 is identified as a palustrine forested seasonally flooded wetland on the NWI maps <br />(USGS 2024; Service, n.d.). ERO believes these features would be considered jurisdictional due to their <br />continuous hydrological connections to St. Vrain Creek. At DP5, vegetation was dominated by curly dock <br />(Rumex crispus) and met the dominance test for hydrophytic vegetation. At DP5, the soils contained a <br />matrix color of 10YR 3/2 with a redoximorphic concentration of 10YR 3/4 and met the hydric soil <br />indicator redox dark surface. Hydrology indicators met at DP5 included surface soil cracks, geomorphic <br />position, and a successful FAC-neutral test. <br />Due to the similarity between W3 and W4, a DP was not taken in W4. The only difference between the <br />two wetlands is that W4 had a canopy dominated by peachleaf willow with an understory containing <br />curly dock and smartweed (Photo 7). Hydric soils were assumed present based on the dominance of <br />hydrophytic vegetation and presence of wetland hydrology (geomorphic position and a successful FAC <br />neutral test). <br />Uplands adjacent to W3 and W4 (DP6) were dominated by western wheatgrass, field bindweed <br />(Convolvulus arvensis), and smooth brome (Bromus inermis). Indicators of hydrophytic vegetation were <br />not met at DP6. A soil sample was not taken at DP6 due to the lack of indicators of hydrophytic <br />vegetation and wetland hydrology. No primary or secondary hydrology indicators were met at DP6. <br />Slope Wetland (Wetland 5) <br />W5 is a slope wetland in the center of the project area (Figure 2; Photo 8). W5 is not identified on the <br />NHD; however, it is mapped as a palustrine emergent persistent temporarily flooded PEM1A on the NWI <br />map (USGS 2024; Service, n.d.). W5 has a continuous hydrological connection to the unnamed tributary <br />to St. Vrain Creek. ERO believes this feature would be considered jurisdictional. Vegetation in W5 (DP7) <br />was dominated by foxtail barley, reed canarygrass (Phalaris arundinacea), and fowl bluegrass (Poa <br />palustris) and met the rapid test for hydrophytic vegetation. At DP7, the soils contained a matrix color of <br />10YR 2/1 with a redoximorphic concentration of 7.5YR 3/4 and met the hydric soil indicator redox dark