RES 06035 - Laserfiche WebLink

Chapter 4 Environmental Setting, Impacts, and Mitigation Measures F. Geology, Soils, and Seismicity The City of Pleasanton recognizes impacts related to seismic hazards could occur as a result of the type of development proposed. Therefore, the Specific Plan specifies that any proposed development in the Plan area must conform to the policies and programs of the Pleasanton General Plan, and any development that occurs in the area must conform to the Uniform Building Code and other applicable state and local seismic safety regulations, These requirements, which are existing law, are intended to mitigate potential risk to development from seismic events to the maximum extent feasible based on current knowledge and technology, Even with complete compliance with seismic safety policies and requirements, seismic risk to property and human life remains that cannot be fully mitigated, However, most of the development and public spaces that would be created by the proposed project (Le, open space, ballfields, parks) are, in general, among the least dangerous places to be during an earthquake No adverse environmental impacts relating to seismic hazards would occur because the Specific Plan contains adequate provisions to mitigate these potential impacts, (2) Soils Management Some grading would be required to implement the proposed project. Some of the soils that would be subject to site grading have geotechnical properties that, if not properly managed, could cause adverse impacts to site improvements, Many of the soils underlying the Plan area have moderate to high shrink/swell potential. This condition occurs when expansive soils undergo alternate cycles of wetting (swelling) and drying (shrinking), During these cycles, the volume of the soil changes significantly. Structural damage, warping, and cracking of roads and sidewalks, and rupture of utility lines may occur if the potential expansive soils were not considered during design and construction of improvements, Although the movement is slow, structures on and within the soil can deform in response to the movement, resulting in tilted fences, cracked pavement, or building foundations, The City of Pleasanton recognizes impacts related to adverse soil conditions could occur as a result of the type of development proposed, Therefore, the Specific Plan states that the all projects completed under the plan will comply with General Plan policies addressing adverse soil conditions, The General Plan contains the following policies addressing adverse geologic conditions: . Program 5,1: Require site-specific soils studies for all new development prior to the issuance of building permits and prior to the approval of final improvement plans in areas with "Moderate," "Moderate to High," or "High" hazards for the following geologic hazards: seismic shaking, lateral spreading, differential settlement, lurch cracking, liquefaction, erosion, and expansive soils, 75