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Water Storage Pond Compacted Clay Liner Parcel 1, S'/2 , SW'/4 , Section' 35, T1S, R67W Adams County, Colorado exposed in the quarry beneath the aggregate - will be constructed to isolate the pond from the natural groundwater in the surrounding soils. Although. grading plans were not available for our review, we understand that the quarry floor will reach depths of about 65 feet below the adjacent original grades surrounding the quarry. If proposed construction, including the anticipated site grading or loading conditions, differ from those described above, or changes subsequently, GROUND should be notified to re-evaluate our recommendations in this report. SLOPE STABILITY MODELING Slope stability analyses were performed on a representative cross section through the proposed reservoir wall using generalized subsurface profiles based on the materials as encountered in the test holes. The temporary slopes were considered to be slope configurations which would be required to stand for only limited periods of time. Stability calculations were performed with the Slope/W computer program, published by Geo-Slope International, of Calgary, Alberta, Canada, copyright 2004. Output from the program, presented the lowest factors of safety against failure obtained for each condition, according to the Morganstern-Price method are presented in Appendix A. The parameters used to model the project earth materials also are presented in the Appendix A. Values for the alluvial sands and gravels were based on field and laboratory moisture and density tests, and on penetration resistance values through the correlation presented by Bowles (Foundation Analysis and Design, 2n° Edition, McGraw- Hill Book Co., 1977). The values for the clay liner material were based on the data obtained from testing of a re-molded sample of the material. The bedrock values were assumed, based on various published and unpublished values and GROUND's experience with similar sites. (The bedrock parameters do not affect the results strongly.) These parameters are considered to be conservatively representative of the site soils and bedrock. The input values used for the 'miscellaneous fill,' however, are necessarily assumed. Those materlal(s) have not yet be identified or placed. We have assumed that clayey soil and bedrock materials will comprise the bulk of those soils, together with on-site silts and sands, as well as possibly imported materials. Again, the values used for the slope Job No. 09-3090 GROUND Engineering Consultants, Inc. Page 2