2020 Local Hazard Mitigation Plan

City of Irvine

of the facilities vulnerable are bridges within the City. Residents may find that street lighting and traffic signals may be temporarily disabled if the inundation area interferes with the electronic systems that control them. The rapid inundation of water would sweep up any debris, which could block roads, impeding the flow of traffic. Water would most likely inundate roadways and other low-lying, flat areas, such as parking lots, open spaces, and schoolyards. People’s mobility in these areas would likely be restricted or even impossible in severe scenarios. Any unprotected or unhoused mechanical or electronic equipment that is not properly elevated would become waterlogged and inoperable until crews are able to conduct repairs or replacement, if necessary.

TABLE 4-4: Dam Failure Hazard Threatened Populations

Peters Canyon Dam

Villa Park Dam 5,870 2,401

Rattlesnake Canyon

Sand Canyon

Santiago Dam

Syphon Canyon

City of Irvine 256,877 92,869 $95,573

Threatened Population Metric

Population Households

5,918 2,046

15,152

1,312

11,639

14,068

5,263

608

4,181

5,118

Median household income

$105,429

$123,600

$52,217

$100,185

$121,700

$88,327

Percentage of households with at least one person living with a disability Percentage of households living under poverty limit Percentage of households with one member aged 65+

18.6%

13.9%

14.5%

15.3%

14.9%

15.7%

5.8%

11.0%

10.5%

16.4%

15.0%

11.1%

14.2%

13.2%

5.8%

10.3%

42.1%

9.3%

10.3%

8.8%

19.5%

San Joaquin Reservoir and Sand Canyon Spillway are not included in this analysis due to the limited inundation area and lack of downstream impacts.

Diseases and Pests

Physical Threat

Agricultural Pests Agricultural pests would not impact physical assets in Irvine. Since agricultural pests would be limited to agricultural properties within the City as well as ornamental plantings (citrus trees, bushes/shrubs, etc.), it is expected that some of these assets could be impacted in the future. This future impact is not anticipated to affect the City’s residents or b usinesses significantly. Epidemic/ Pandemic/ Vector-Borne Disease Since diseases only affect the human body, there is no possible way that an epidemic, pandemic, or vector- borne disease could directly threaten physical assets in Irvine. Tree Mortality A serious outbreak of pests, such as the Gold Spotted Oak Borer, Invasive Shot Hole Borer, or Asian Citrus Psyllid, in Irvine could threaten the City’s urban forest, leading to an episode of intense tree mortality. The City recently conducted an inventory of trees ( Figure 4-3 ). Many of these trees have been impacted by invasive pests (Invasive Shot Hole Borer, Gold Spotted Oak Borer, and Palm Weevil). Part of the tree inventory process is the identification of impacted trees that require monitoring and/or removal. Based on the City’s current inventory, the City estimates the value of their tree assets at approximately $181 million. Understanding that a portion of this inventory will require replacement every year, trees that are

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