SR 06:209 - Laserfiche WebLink

feet wide, making avoidance (e.g., building setbacks) the most appropriate mitigation method. The consider the style and complexity of faulting at the site and the accuracy of the fault location. Although there is general agreement on a 50-foot setback for buildings adjacent to a known fault trace, the appropriate setback for habitatable buildings adjacent to an inferred or hidden fault trace is not as clear. Due to the uncertainty of the exact location of the fault and therefore any potential ground rupture, this General Plan recommends a IOO-foot habitable building setbaclr from the inferred fault location. Geologic Hazards T ~n,-ldl,-lp", For general planning purposes, a high potential for active landsliding should be considered to exist on all slopes bordering the Amador Valley and other hill slopes within the Planning Area, unless site- specific geotechnical investigations can demonstrate local stability. However, the Southeast Hills are generally more stable and less prone to slope failure than the eastern slopes of the Pleasanton Ridge. The General Plan Map responds to the potential for landsliding by designating a majority of the land on Pleasanton Ridge as Agricultural and Grazing and Parks and Recreation, and the Southeast Hills as Public Health and Safety. Flatter and generally more stable portions of these areas are designated for Low Density Residential development surrounded by Rural Density Residential development because the potential for landslides and other hazards appears to be sufficiendy low in these areas. Where development is permitted, the City's policy is to require that site-specific geologic investigations and soils reports be prepared and submitted during the plan review process for any type of development proposed. These studies recommend measures to mitigate any potential hazards related to grading, construction, and operation of a development. The City's consulting geologist reviews the reports for acceptability. Projects must address the recommendations of the City's geologist. Sites must be shown to be stable during adverse conditions such as saturated soils and ground shaking, and during grading for roads, installation of infrastructure, and the creation of building pads. Reports must demonstrate that structures will sustain no more damage due to slope instabilities than damage sustained by a typical building constructed to current Califtrnia Building Code standards on stable soils when exposed to moderate ground shaking. In unstable areas, the City seeks to minimize grading of slopes for construction or slope-stability repairs, limit grading only to where it is essential for development, and prohibit major grading where existing slopes are 25 percent or greater. Areas with slopes of 25 percent or greater are generally designated on the General Plan Map as Public Health and Safety. (!be Land Use Element discusses the calculation of residential density where slopes, landslides, or geotechnical hazards exist on a property.) PublK: Safer}' 082906, clean V-12 City Council 8/29/2006