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3. Excavation shall not occur within the 25-foot setback from the park's boundary. Working slopes shall not exceed 2:1, and final slopes after reclamation will not exceed 3:1. Should the park expand to increase public usage near the excavation area and prior to the final sloping for reclamation, the quarry operator will place a temporary chain link fence along the boundary of the excavated slope for the protection and safety of the general public. The Department of Parks and Recreation will contact the quarry operator at such time. These mitigation measures are acceptable to the Department of Parks and Recreation and are incorporated into the Conditions of Approval. Slope Stability The project site abuts a bluff, which is a part of the parcels containing the County Park and four homesites along Mackville Road. It is proposed that final slopes be reclaimed to 2 horizontal to 1 vertical except along the park boundary where final slopes will not exceed 3 to 1 in accordance with the mitigation measure outlined above. When excavation abuts property containing existing structures or property which has the immediate potential for the construction of structures, Section 9-1415.3[k][5] of the Development Title states that excavation shall at no time be closer to a property line than a line projected on a slope of 1:1 from the property line to the toe of the slope. The applicant is proposing 2:1 finished slopes,which is consistent with Development Title requirements. However, there is concern that working and finished slopes may undermine the existing bluff. In order to mitigate this potential impact, the following Condition of Approval will be required: 1.k.(3) Prior to the quarry operations progressing to a location which may impact the bluff located at the northeast boundary of the quarry site, a geologic and engineering analysis shall be conducted, and all recommendations of the analysis shall be followed to ensure the stability of the bluff. Flooding/Drainage The limit of excavation is approximately 500 feet away from the bank of the Mokelumne River. This distance,recommended by County Flood Control, moves the quarry out of the 500-year flood zone. The applicant is not proposing retention ponds for storm drainage due to the high percolation rate of the soils in the project area. Should water collect in the quarry,the applicant is proposing to pump excess water to the Mokelumne River. The applicantwill be required to obtain a Discharge Permit from the Central Valley Regional Water Quality Control Board should pumping be required. Documentation provided by the applicant, including Test Hole Reports,surrounding well logs,and information from the adjacent quarry to the south, indicates that the excavation will not come into contact with groundwater. The applicant is required to contact the Central Valley Regional Water Quality Control Board and obtain all required permits should ground water be encountered. Habitat and Biology The State Department of Fish and Game and the U.S. Departmentof Fish and Wildlife have concluded that the proposed quarry will not significantly impact sensitive species or habitat. The distance of 500 feet from the Mokelumne Riverto alleviate flood impacts also moves the limits of excavation outside the riparian corridor. In addition,the 500-foot setback will prevent the quarry from becoming a fish trap during flood events. San Joaquin County QX-99-2\Reed .� Community Development Page 4