PC-92-25 - Laserfiche WebLink

should include all landslides and potential landslides on-site and all landslides off-site that may impact on-site development, as well as landslides on-site that may affect adjacent properties. This work should include preparation of a detailed geologic map and performance of a subsurface investigation within each area with a high potential for future slope movement. A thorough slope stability analysis should include considerations of the maximum seismic accelerations which might be transmitted, especially in regard to saturated soil conditions. The project engineer and engineering geologist also should provide recommendations for location of a suitable building envelope for each hillside lot. Additional recommendations should be made as to the hazard feasibility of developing lots heavily-impacted by landslides, landslide repair, or potential slope failure. (MM 9.A.I) 55. A detailed construction plan should be prepared by the project's geotechnical engineer and/or certified engineering geologist for the stabilization of all on-site landslides and potential landslides, all off-site slides that may affect the project or adjacent off-site developed areas. The depth and lateral dimensions of each landslide should include detailed section and plans showing the limit of work along with detailed grading specifications for performance of the stabilization work. All landslides and potential landslides which could affect the proposed project should be stabilized by the developer before individual lots are sold. (MM 9.A.2) 56. (MM 9 .A. 3) Subsurface and surface drainage water should be controlled so that landslide instigation, initiation or reactivation will be minimized. All storm drainage should be in closed conduits. Concrete ditches with catch basins should be used frequently to catch surface water. A subdrain system should be installed to intercept subsurface water flow. Sediment basins should be installed to remove soils carried in storm water run-off. 57. (MM 9.A.4) The project geotechnical engineer and/or certified engineer~ng geologist should provide detailed recommendations for the setback of structures from cut slopes, fill slopes, natural slopes and buttresses. 58. (MM 9.A.5) The project civil engineer should ensure that all recommendations of the geotechnical engineer and/or certified engineering geologist are reflected in the grading and drainage plans and implemented by the developer. 59. (MM 9.A.6) Lot grading should be performed as part of the overall subdivision grading recommended by the geotechnical and civil engineers... Modifications by builders or homeowners should not be permitted.