Specify property data file
Damage Calculator requires a property dataset in .shp or .csv format. The main source of property data available for use in flood and coastal erosion risk management in England and Wales is the National Receptor Dataset (NRD) Layer.
The property data file specified needs to include particular attributes to enable damage calculator to look-up damage data associated with each property type. It is recommended that the Field Mapping button is clicked to check how Damage Calculator has assumed these fields “map” to the required fields for the analysis. Field mappings can be modified if required, and the revised settings saved.
If capping or writeoff are to be included in the analysis, market values for properties must be set up in advance of using Damage Calculator. This is done by adding an extra field to the property dataset entitled “MarkVal”. Damage Calculator will automatically use these values and compare them against calculated PVD for each property. If an existing market value field is present in the data with a different attribute name, this can be renamed, or field mapping can be used to reference this column as the market value field.
Property Data Column Headings
Property data column headings / fields required are shown in the table below. These are required whether a user created dataset or NRD has been used.
Title | Description | Source | Additional Notes |
|---|---|---|---|
Easting / X | Geographic location | NRD | Field mapping works for both ‘Easting / Northing’ and ‘X/Y’ |
Northing / Y | NRD | ||
mcmcode | Defines type of property | NRD | Must be populated for damages to be calculated |
houseType | Provides detail on residential property types if nrd2014 used | NRD 2014 | Has been replaced by 'bldg_type' and 'class_desc' columns in NRD2021 |
bldg_type | Provides additional detail on residential property type if nrd2021 used | NRD 2021 | Not present in NRD2014 |
class_desc | NRD 2021 | ||
floorArea | Size of property | NRD | If floor area is blank or zero, property is assumed to be upper floor. The only damages calculated will be vehicle and risk to life damages, and the discounted market value in the year the property is written off. If these damages are not required for upper floor properties, the upper floor properties should be removed from the property dataset |
floorLevel | Floor level of property (basement, ground or upper) | NRD | If floorlevel is pU, rU or NA, a property is assumed to be upper floor. The only damages calculated will be vehicle and risk to life damages, and the discounted market value in the year the property is written off. If these damages are not required for upper floor properties, the upper floor properties should be removed from the property dataset If floor level is dB, dG, pG or blank (and floor area is >0), all damage types will be calculated |
markval | ‘Market value’ - required for capping and writeoff calculations | Not included in NRD, must be added by user | - |
threshold | Elevation of property. | Not included in NRD, must be added by user | Elevation above ground must be used if flood depth grids are used. Threshold elevation above ordnance datum must be used if flood level / stage grids are used |
over75 | Numerical data on % of residents in area over age of 75 | Not included in NRD, must be added by user |
|
infirm | Numerical data on % of residents in area with infirmity | Not included in NRD, must be added by user | |
natarea | Numerical value representing the building type ('nature of the area') | Not included in NRD, must be added by user | |
fws | Numerical Flood Warning Score | Not included in NRD, must be added by user | |
flood level / depth data (multiple columns) | Provides damage calculator with flood depth / level data if 'Use Flood Information in Property File' option selected. | Not included in NRD, must be added by user | Only required if 'Use Flood Information in Property File' option has been selected on the 'Calculation Information' tab |
Using Results in depth format or stage format
Grid or attribute data can represent either a water level (in mAOD) or water depth (m). The ‘threshold’ field in the property dataset must be populated differently depending on which has been used.
If the grid or attribute data used represents a water level (mAOD), a threshold must be provided which is also in mAOD, representing the distance of the building threshold above ordnance datum.
If the grid or attribute data used represents a water depth (m), a threshold must be provided which represents the distance of the building threshold above the ground. For example, this may be 0.15m for all properties.