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. . 00:.Q99 Most of the area that would be impacted by inundation and enlargement of the dam consists of upland shrubs and grasses, Several acres of wetlands would be flooded in the areas adjacent to Elkhead Creek at the upper end Of the reservoir. New wetland areas, similar in size to the inundated wetland area, would be expected to develop within the delta of the enlarged reservoir several years after project construction. The wetland areas are not believed to be habitats used by any of the endangered species addressed previously. Enlarged Embankment Raising Elkhead Dam to elevation 6,420 MSL would be accomplished using conventional geotechnical downstream earth embankment raise techniques. Therefore, the downstream toe of the enlarged dam would extend approximately 300 feet downstream of toe of the existing dam. Placement of new homogeneous dam shell material would be preceded by excavation of the clay and gravel layers above the foundation rock, removal of the top two feet of the existing downstream dam slope material and removal of the top 10-feet of abutment surface material. Several small, isolated wetland areas located downstream of the existing dam which have developed as a result of reservoir seepage would be filled as a result of the enlargement. These areas would be expected to redevelop downstream of the toe of the enlarged dam over a period of several years. Construction of the enlarged embankment would not adversely affect habitat used by any of the endangered species addressed previously. Staging of construction activities during the dam enlargement would take place in areas immediately adjacent to the downstream face of the existing dam. Staging would include the stockpiling of gravel and other earthen material and construction materials, construction of temporary roads and activities associated with activity of heavy equipment. Required gravels and earthen materials would be taken from several areas within the enlarged reservoir area or brought in from regional aggregate suppliers. All impacts associated with construction staging would be temporary in nature. Disturbed areas would be reclaimed to their pre-existing conditions or, if flooded, to a suitably contoured bottom configuration following completion of the project. Temporary impacts resulting from construction staging would not adversely affect habitat used by any of the endangered species addressed previously. Emergency Spillway Enlarging the dam to elevation 6,420 MSL would permit an emergency spillway to be cut through a saddle in the right abutment to an adjacent drainageway which joins Elkhead Creek one mile downstream. The new emergency spillway would have a crest elevation of 6,409 feet and would be lined with grouted riprap or roller compacted concrete (RCC) and would have transverse erosion control groins positioned at regular intervals the full length of the spillway route. A few developed home sites in the adjacent drainage way would need to be I purchased and relocated, however, the valley would remain in agricultural use. A drainageway easement of approximately 30 acres in size is necessary to accommodate flooding which is expected to occur less frequently than once in 100 years. Construction of the new emergency spillway would not adversely affect habitat used by any of the endangered speCies addr~ssed previously. , Recreational and Other Facilities Existing recreational facilities, miscellaneous facilities associated with utilities, and small outbuildings in the area would be relocated to accommodate the enlarged embankment and reservoir. Impacts associated with these relocations would be very minor and would not adversely affect habitat used by any of the endangered species addressed previously. 12 :lic.3