Dependency Vulnerability Assessment

Since infrastructure systems enable the fundamental functions of communities, it is important to plan for critical infrastructure dependencies and the potential disruptions to essential services they may present.

To have the greatest resilience benefit, communities need to understand where they can and cannot afford to have a disruption of infrastructure systems. To gain this understanding, planners should identify key infrastructure dependencies that present risks to fundamental functions.

Asking pointed, thought-provoking questions during planning is an effective way to identify dependencies that pose risks to a community. Here are several different approaches to determining infrastructure dependencies. These three question approaches are not mutually exclusive and can be used individually or in combination during sessions with planning staff, discussions with infrastructure system owners and operators, and community meetings to focus discussions around dependencies.

Approach #1 - Begin at the Backbone

This approach may be most successful with participants such as public works personnel and utility owners/operators, as examples, who are familiar with infrastructure systems that serve the community. Evaluating how each infrastructure system enables essential community functions, services, and facility operations can lead to an identification of critical dependencies.

• What are the infrastructure systems that serve your community? (Make a list)
  • What service does each infrastructure system provide?
    • What types of critical facilities within the community require these services to operate?
      • What are the critical functions these facilities enable within the community?

Approach #2 - Draw on Past Experience

This approach can be effective regardless of a group’s makeup. Having participants recount the impacts they experienced during a past hazard event can lead to a discovery of the community’s dependence on infrastructure systems and the dependence of those systems on each other.

• Can you think of any examples of infrastructure facilities or systems that have been damaged during a recent incident?
  • What were the consequences of that incident?
  • Did any other facilities or systems rely upon the affected facility or system for their operation?
  • How long did it take to recover the service provided by that facility or system?

Approach #3 - Focus on the Essentials

This approach may be most effective when used with a group consisting of community officials, developers, and planners. Identification of a community’s functional needs and how those are enabled by infrastructure systems can lead to an identification of critical dependencies.

• What are the critical functions that enable your community to remain viable?
  • What are the critical facilities that support each function? (Make a list)
    • For each facility type, what infrastructure systems/services are needed to enable the facility to operate?

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