Geologically Hazardous Areas

Geologically hazardous areas are those areas susceptible to erosion, landslides, earthquakes, or other geological events. 

EROSION

Erosion hazard areas are areas in the City underlain by soils that are subject to severe erosion by surface waters from storms and human activities. These areas are protected to prevent soil from eroding off a property and carrying harmful chemicals into streams and lakes. 

Erosion prevention is also addressed by the City's Storm and Surface Water Management Program in the Department of Public Works. 

LANDSLIDES

Landslide and seismic areas are protected due to the potential threat to the health and safety of the public that may occur when something happens that causes the ground to have a catastrophic failure. 

In landslide hazard areas (which includes steep slopes), a minimum buffer of 50 feet shall be established from the top and toe of the slope to protect structures that may be impacted by a landslide event. The buffer can be extended as required to mitigate a landslide or erosion hazard or to protect the public health, safety, and welfare. Alternatively, the buffer may be reduced or removed, based on a critical areas study, the City determines that the critical area will be adequately protected.

Often, field verification and site-specific assessment are required to delineate geologically hazardous areas and associated buffers. Geologic conditions are field verified by a qualified geotechnical professional for certain development depending on the location and type of geologically hazardous area.