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3.2 Comments/Applicant's Response/Corps Resolution. Comments received have been reviewed and aze summarized below. The infomtafion in italics is the Corps' response to the comments. 3.2.1 Federal Agencies. 20 Apr 2003 1. At the site meeting it was presented that two additional mining cells are planned but not indicated on the maps. While mining these two areas may not directly impact waters of the US, there may be indrrect impacts to adjacent waters of the US due to altered hydrology and mining practices. The consultant submitted the complete mine plan map, which shows Cells 1 and 1 as well as Cells 3 and 4. Cells 1 and 2 are impacting an open field on the western side of the project site. Cell l will be impacting anon- jurisdictional isolated wetland. This wetland loss will be compensated for through the mitigation plan. As answered by the consultant, the great majority of the wetlands on theproject site are located topographically above the mining cells and derive their water from un-impacted sources (the ponds or irrigation waters to the west). These wetlands cannot be impacted by the scope of the proposed project. Of the remaining wetlands, the oxbow wetland segment between cells 3 and 9 derives its water from the ponds above. Therefore, this wetland is not likely to be impacted by mining. The wetlands along the toe of the terrace slope have not been impacted, as determined by the empirjcal conditions on-site to date (mining has already occurred downgradientJ. 2. The Applicant has stated that it would be uneconomical to avoid the oxbow wetlands and split cell 4 into two separate mining cells. It is based upon a stated reduction of 30.3% at the two cells. However, the other mineable reserves (in cell 1 and 2) appeaz to not be included in the calculation. This percentage reduction is artificially high because it does not take in al] the mineable reserves that are planned at the project site. The consultant submitted a modified table showing economic data for all mining cells on site. See the "Resource Evaluation "section of the comment response letter dated October 17, 2003. 3. It was mentioned at the site meeting that there are no current plans to use the mined out pits for water storage/augmentation. However in the future this may change if a satisfactory offer is made. There is great demand for using gravel pits for water storage in the Front Range of Colorado. If these were to be used for water storage, the pits would have to be lined with bentonite or an impermeable slurry wall would be constructed azound the perimeter of the pits. This raises concerns to adjacent wetlands and any proposed mitigation azeas. This is a change in the project purpose. All activities that the applicant plans to undertake that aze reasonably related to this project should be included in the permit application. The pemrit, if issued, should be conditioned so that in the future if water storage is realized at this site, any existing wetlands aze secure and Corps authorization will be required and the project re-evaluated. According to the consultant/applicant, !here are no future plans for water storage at this project site. Shoula water storage ever take place, the water sources for the proposed mitigation wetlands are located topographically above the post-mining cells, and a change in project purpose will most likely not effect them. A special condition will be implemented to clam that no change in project purpose, or in the nature of the permitted activity, is authorized without prior approval by the Corps of Engineers. 4 . There is a concern about potential impacts to other wetlands on site with regard to changing land topography/hydrodynamics from the mining. Project: Grccn & Croissant Aggregate Mining Applicant: Loveland Ready Mix, lnc. Pg 13 of s3 Corps File No: 200180205 Waterway: Big Thompson Wetlands, Weld County, CO