The purpose of the safety element is to help protect the community from any unreasonable risks associated with seismically-induced hazards (surface rupture, ground shaking, ground failure, seismic and dam failure) and other geologic hazards, such as slope instability or subsidence, and flooding and fires. Due to the rural setting of the Community Plan, natural hazards, such as wild fires and flooding are of particular concern. While this element focuses on natural hazards, other public safety concerns are also addressed.
Due to the mountainous setting of Mountain Springs and the seismic history of the Sierra Foothills region, geologic hazards are of particular concern. The Community Plan is not located within a Fault-Rupture Hazard Zone as delineated by the Alquist-Priolo Earthquake Fault Zoning Act, and no active faults are known to reach the surface in the Community Plan Area. Based upon the Tuolumne County General Plan Geohazard Diagram for the Sonora Quadrangle, there is potentially a northwest-trending geologic fault bisecting the Community Plan Area (Source: Tuolumne County G.I.S., George Ball G.I.S. Analyst). Refer to Figure 1-2. Potential safety concerns are limited, however, since the existing golf course is the primary land use in the vicinity of the fault. In this way, the impacts of a seismic event are reduced.
The Mountain Springs Community is nestled within the Sierra Foothills where the gently rolling terrain gives way, in places, to relatively steep slopes. Development on steep slopes can reduce soil stability, leading to an increased risk of landslides, mudslides and other natural hazards. The Community Plan limits land use designations on steep slopes primarily to Open Space and Open Space easements.
The Community Plan lies within the Sullivan Creek and Curtis Creek watersheds. Sullivan Creek flows through the western portion of the Community Plan. Flores Creek, a tributary to Curtis Creek, also flows through the Mountain Springs Community. All three creeks are perennial streams, though flows are restricted during the dry summer season. The potential for flooding is limited, due to the minimal size of these streams and the generally rugged relief of the area. The Community Plan identifies the riparian corridors located within the Community Plan within Open Space or Open Space easements or within land designated Parks and Recreation, thereby further reducing the potential for flood damage to structures.
