Laserfiche WebLink
Wattenberg Lakes Gravel Mining <br /> Revised Compensatory Mitigation Plan <br /> Weld County, Colorado <br /> provide nutrient processing to the stream system. Wetland functions would be enhanced by creating a <br /> more diverse wetland system, improving water quality by reducing the nutrients entering the South <br /> Platte River, providing more connectivity and reducing barriers between wetland areas, increasing water <br /> distribution through the wetlands by creating large wetland complexes, and enhancing adjacent areas <br /> with native upland vegetation. <br /> Wetland Mitigation <br /> Proposed compensatory mitigation for permanent wetland impacts would be permittee-responsible,on- <br /> site, in-kind, and at a 1:1 ratio. The 32.57 acres of wetland mitigation required would be created <br /> primarily in the Phase III mining area (Figure 4). Wetlands would be supported by groundwater,which <br /> was the primary hydrology source for the wetlands impacted by the project. The wetland areas would <br /> be a combination of palustrine emergent, scrub-shrub, and saltgrass wet meadow wetlands as described <br /> above. The created wetlands would be seeded with a wetland seed mix and planted with a mix of <br /> wetland plugs and willow stakes. Per the IP authorization,the mitigation areas will be seeded with the <br /> following native species(Table 1). A detailed planting plan that provides information about the <br /> herbaceous seed and plug plantings, and the quantities of proposed tree and shrub plantings is being <br /> developed and will be provided at a later date. <br /> To establish baseline conditions, Holcim had groundwater data collected monthly from groundwater <br /> monitoring wells starting in January 2002. Furthermore, in accordance with Special Condition G and <br /> Special Condition S of the IP authorization, Holcim has been conducting groundwater monitoring for the <br /> project since 2006,to document detailed site conditions and groundwater levels in the area. Based on <br /> the mitigation plan authorized in the IP,elevations for the wetland mitigation areas will be determined <br /> from baseline groundwater data; however, due to the proposed reservoir modifications,which include <br /> expanding Pond 1 and creating a larger slurry wall in the southwest section of the project area, <br /> additional groundwater analysis will be necessary to understand final groundwater elevations in the <br /> mitigation areas. Mounding is anticipated to occur from the slurry wall along Pond 3,which could result <br /> in higher groundwater levels in the mitigation areas. However, shadowing may occur from the <br /> construction of the slurry wall around Pond 1,which may reduce groundwater levels in the mitigation <br /> area. Due to these potential effects to groundwater, Holcim is proposing to continue monitoring <br /> groundwater elevations in these areas until 1-to 2-years post-construction of the slurry wall around <br /> Pond 1. Once groundwater elevations have stabilized,wetland mitigation would be constructed to the <br /> appropriate elevations to meet hydrology requirements. Although this may result in a temporal delay in <br /> wetland mitigation,the South Platte Valley wetlands created on the east side of the South Platte River <br /> will remain as temporal wetland mitigation until the final wetland mitigation areas are established. <br /> ERO Project#22-078 6 <br /> ERO Resources Corporation <br />