The Scoping Tool computes economic losses through direct losses from structures and their contents. 

Exposure

The NSI provides the type of structures, exposed value, population, and location of the structures. This foundational data layer strives for national consistency, but due to inconsistent data availability is forced to fill data gaps with assumptions. This means that the NSI may not be perfect in every study area. The user should review the inventory data and understand how well it describes the exposure in their study area. Important attributes are listed in the table below. Additionally consider the count of buildings within the study area because exposure can be understated or overstated if the number of structures in the study area are misrepresented in the NSI.

FieldDescriptionType
fd_ida unique identifier relating the result structure to the NSI structure databaseint
xthe structure's x locationfloat64
ythe structure's y locationfloat64
structure valuean estimate of the expected annual damages for structure loss at this structurefloat64
content valuean estimate of the expected annual damages for the content loss at this structurefloat64

Vulnerability

Each structure in the NSI has a damage category and an occupancy type. Each occupancy type is associated with a family of damage functions that describe the vulnerability of that occupancy type. For coastal residential properties, foundation type and foundation height are used in conjunction with the wave height to define the vulnerability of structures. Ensure proper review of the occupancy types,  foundation types, and foundation heights to ensure proper damage functions are used for loss.

FieldDescriptionType
fd_ida unique identifier relating the result structure to the NSI structure databaseint
xthe structure's x locationfloat64
ythe structure's y locationfloat64
foundation typeall of the hazards experienced by the structure as a json byte blobfloat64
foundation heightthe foundation height provided by the NSI utilized during the damage computestring
occtypethe occupancy type for the structure, limited to the NSI 40 occupancy typesstring

Consequences

CHART leverages the go-consequences engine to combine the Hazard Data, the NSI, and the damage functions to compute loss for each AEF in the hazard data see figure (xxxx update when figure numbers are set). The direct loss calculation is applied for each structure impacted by each AEF. This section outlines the computation steps for computing loss for a given AEF at a given strucure.

Economic Loss

Economic loss is calculated based on a family of damage functions. Based on the structure's occupancy type and foundation type the appropriate damage function family is selected. The hazard is assumed to be coastal, so the computation logic evaluates the wave height. The appropriate damage function is selected based on the wave height. The total damaging depth is computed using the formula described in the hazards documentation.

Computation Steps for a given AEF:

  1. Generate Structure
  2. Determine Structure's location
  3. Query Hazard dataset for hazard information
    1. compute total damaging depth.
  4. Find appropriate structure damage function for the occupancy type, foundation type, and wave height.
  5. subtract foundation height from total damaging depth provided by the hazard.
  6. Apply resulting depth to damage function to get a loss ratio for structure value
  7. multiply loss ratio times structure value
  8. repeat steps 6 and 7 for contents.