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Mc Joe Intermill ~~ May 6, 2005 Paget civir RFSwuecr.s Other mitigating factors with regard to wave action erosion include: • The proposed maximum water surface elevation for Pond 2 (closest to Highway 85) is 4,937.5 ft-MSL. The ground surface along the western margin of Pond 2, parallel to Highway 85, ranges in elevations from 4,940 ft- MSL to 4,944 ft-MSL providing freeboard from 2.5 feet to 6.5 feet. The maximum east to west wave runup was calculated to be approximately 1.6 feet for the proposed project configuration and the maximum reservoir setup was calculated to be less than 0.05 feet. • The proposed 4 to 1 finished slopes are considered a very safe and maintainable slope that naturally resists erosion by allowing waves to dissipate their kinetic energy on the relatively flat slope. Further, the owner of the water storage facility is liable for the safety of the project in accordance with State Statutes and has a vested interest in protecting the slope liner integrity. Should any wave erosion occur in the embankments, the problem would be quickly repaired. • Low occurrence of maximum prevailing winds arising from the east would limit any erosion on the west side of the reservoir. Refer to the attached wind rose information (Attachment A). • The operating level of the reservoirs will vary as filling and emptying occur to meet augmentation requirements of the Owner. However, even 'rf the reservoir levels were held constant throughout their life, wave action erosion would be limited. • Even if we had no erosion protection, wave erosion on soil embankments where a constant water level is maintained has been observed to cut vertically into the slope at the normal water line, creating a flat, horizontal shelf and then a 1 to 2 feet high vertical face. The height of the vertical face is dependent on the original embankment slope and soil properties. The horizontal shelf dissipates the energy of the wave action and erosion is arrested. The variable reservoir level, erosion resistant properties of the Zone 2 material and flat beginning slope (4:1) would limit the vertical face height, even if no maintenance was completed by the reservoir owner and a constant water level was maintained. • Ponds, lakes and below grade reservoirs are not known to "migrate" or be dynamic systems with respect to wave erosion movement in the State of Colorado. We believe that this project has gone above and beyond the reasonable care to protect adjacent properties from the potential for damage. Please call if you have further questions or concerns about the Lupton Lakes Project. Sincerely, Civil Resources, LLC Brad L. Hagen, P.E. Civil Engineer! Principal Z:bmjeclslSW Investment Group-1231SW TKO Joint VenWre1DMG PERMITl4tlequaq Reviex10bjector IettersICDOTCDGT-Malerosgn-D:A305.tloc