City of Irvine
2020 Local Hazard Mitigation Plan
TABLE 4-7: Flood Hazard Threatened Populations
Flood Hazards (1%)
Flood Hazards (0.2%)
City of Irvine
Threatened Population Metric
Population
434
6,031
256,877
Households
98
2,196
92,869
Median household income
$142,463
$92,855
$95,573
Percentage of households with at least one person living with a disability Percentage of households living under the poverty limit
12.3%
12.7%
5.8%
11.6%
11.5%
13.2%
Percentage of households with one member aged 65+
4.8%
10.6%
19.5%
Geologic Hazards
Physical Threat
Landslides Landslides pose a threat to a variety of City facilities. Table 4-8 identifies the facilities located within the Deep-Seated Landslide hazard zone identified in Figure 4-5 . A majority of these landslide hazard zones are in the foothills of the Santa Ana Mountains and San Joaquin Hills. These areas are characterized by steep slopes, which during long periods of rainfall, can trigger a landslide. In total, deep-seated landslides could cause over $50 million in losses based on the 30 CFs and 7 FOC located in this zone. In addition to this zone, the City also mapped the California Geological Survey’s Earthquake Induced Landslide zones ( Figure 4-6 ), which identifies a smaller landslide hazard footprint. Additional loss estimation of this hazard zone was not conducted, as the losses are already accounted for in Table 4-8 . Table 4-8 Critical Facilities and Facilities of Concern (Deep Seated Landslide) Category Number of Facilities Potential Loss** Critical Concern City Vital Operations - - $0 City Community Centers 3 - $17,743,074 City Resident Services - 2 $1,604,745 City Recreation Support - - $0 Bridges 27 - $31,346,880 Schools* - 5 N/A Total 30 7 $50,694,699 * Replacement Values unavailable ** Based on the City of Irvine insured replacement values Subsidence Subsidence can influence both the built and natural environment. Because water lines are gravity-driven, a change in elevation as a result of subsidence could make the system more inefficient. Sinking of the ground could also reduce the distance to the groundwater table, which could raise the risk of contamination from hazardous materials. Subsidence could also irreversibly decrease an aquifer’s capacity
98
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