City of Irvine
2020 Local Hazard Mitigation Plan
Closures may cause traffic to be re-routed, resulting in an increase in traffic congestion on local roads. Motorists unfamiliar with the area may drive hastily and may collide with pedestrians or cyclists on the road, which include seniors and lower-income persons. In a severe transportation incident, traffic may come to a complete standstill and idle on the roadway, resulting in more air pollution. Groups with respiratory conditions, such as seniors or children with asthma, may have difficulty breathing during the period of the transportation incident. Infrastructure Failure Infrastructure failure incidents are expected to threaten any groups who live next to the area of failure. A roadway failure would impact local circulation, and any residents and businesses in the vicinity would be directly affected. Similar impacts would occur as a result of pipeline, bridge, and/or storm drain failure. Depending on the size of the failure and the location, the impact on the community can become significant. In some jurisdictions, the loss of a bridge re-routes traffic for months while reconstruction occurs. These types of inconvenience can inordinately impact vulnerable populations in similar ways to transportation accidents, as described above. Additional information regarding the August 2019 incident that caused a power outage in the City is located in Chapter 2 of this document. A failure of this type can have a significant effect on vulnerable populations that rely on electricity for health and/or support services.
Seismic Hazards
Physical Threat
Fault Rupture The City has numerous faults that have been mapped and identified in the San Joaquin Hills and the foothills of the Santa Ana Mountains. Figure 4-8 identifies these mapped faults with the City’s CFs and FOC. Per the mapping, these faults are not considered active as defined by the California Geological Survey; therefore, the risk associated with fault rupture is lower than other areas of Orange County and southern California. Table 4-13 identifies the CFs and FOC located within 500 feet of these mapped fault segments. Based on this table, potential losses associated with fault rupture could amount to over $66 million and affect 4 CFs and 18 FOC. Liquefaction Liquefaction potential is predominantly located within the northern portion of the City, as well as along stream courses in the Santa Ana foothills and San Joaquin Hills. Figure 4-9 identifies the areas susceptible to liquefaction and location of CFs and FOC. Give the extent of the liquefaction zone and density of City facilities; this hazard poses the most significant potential loss. Over $233 million in City assets composed of 78 CFs and 30 FOC are located within these areas. Table 4-14 identifies these potential losses, which includes 70 bridges and 20 schools in the City of Irvine.
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