Coastal Services Center

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Risk and Vulnerability Assessment Steps Societal Analysis Extended Discussion

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Objective(s):

Map special consideration areas; identify vulnerable populations and or areas

Purpose:

Target priority areas for the remaining assessment

Primary Steps:

1. Locate, gather, and process data
2. Assign scores to special consideration areas
3. Target areas for vulnerability assessments and outreach activities

Description

A societal vulnerability assessment examines the vulnerability of people of different ages, income levels, ethnicity, capabilities, and experiences to a hazard or group of hazards.

Special consideration areas are those where personal resources or characteristics are such that their ability to deal with hazards is limited. For example, these areas generally contain higher concentrations of low-to-moderate income households that would be most likely to require public assistance and services to recover from disaster impacts. Structures in these areas are more likely to be uninsured or underinsured for hazard damages, and persons may have limited financial resources for pursuing individual hazard mitigation options.

These are also areas where other considerations such as mobility, literacy, or language can significantly impact disaster recovery efforts. These areas could be most dependent on public resources after a disaster and thus could be good investment areas for hazard mitigation activities. In fact, the primary purpose for defining these special consideration areas in a vulnerability assessment is to identify locations for targeting effective hazard mitigation strategies. By focusing on these areas, communities can help reduce the vulnerability of individuals and also help reduce the requirements for public services as well.

Examples of Vulnerable Populations

In the absence of more detailed, accurate data collected at the local level, publicly available census data at the block or block group level can be used for this analysis. Demographic characteristics can be selected to help identify special consideration areas. In this analysis, eight categories were selected from U.S. Census data and classified as high-need determinant factors:

Percent Non-white Population

Indicates potential language, cultural, or health considerations. Non-white populations may also represent areas where foreign language interpreters may be necessary.

Percent Households below Poverty

Indicates limited resources. Poverty and public assistance income may indicate areas where even moderate damages could have significant financial impacts on residents.

Percent Persons over Age 65

Elderly populations and lack of vehicles may indicate special mobility needs.

Percent Single Parent with Child Families

Indicates areas where special child care considerations could be necessary.

Percent No High School Diploma

Indicates possible need for personal interactivity instead of written communication. Low educational attainment rates may indicate the need for specialized help in dealing with disaster assistance procedures.

Percent Households with Public Assistance Income

Indicates households likely to require public disaster aid (i.e., temporary or long-term housing, money, services, etc.).

Percent Rental Housing

Indicates households where contents are least likely to be insured, making the pursuit of structural hazard mitigation even more difficult.

Percent No Vehicle Available

Indicates possible reliance on public transportation for mobility.

For each category listed, census block groups were ranked and divided into five divisions. Those block groups with percentages in the highest division were given a score of 5, the second highest were given a score of 4, the third highest a score of 3, the next lowest a score of 2, and the lowest a score of 1. After this process was completed for all categories, the scores for each block group were totaled to determine a societal risk summary score.

Combine Risk Areas with Special Consideration Areas

To further target areas for potential hazard mitigation activities, you should identify areas that are located in high-risk zones. The identification of risk areas within the special consideration block groups helps to assess the overall risks to the population and aids in targeting and prioritizing hazard mitigation options. To help prioritize potential mitigation options, conduct a general inventory of structures in the special consideration/high-risk intersections. By providing a count of residential units within these areas, the special consideration households to be targeted for assistance can be summarized, indicating their level of vulnerability to each hazard.

There are a number of ways to complete this type of inventory. In some cases, communities will choose to conduct a parcel-by-parcel driving survey to determine the number and type of vulnerable facilities in high-risk areas. A parcel-based land use inventory, available in a GIS format, can provide the quickest and easiest method of analysis. This inventory can be used to identify the number and type of residential structures located in the special consideration block groups. Residential units can then be given scores corresponding to their hazard risk summary scores.

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