Water damage estimator (Indicator)

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General

What is the Water Damage Estimator indicator?

The Water Damage Estimator indicator is a simplified implementation of the 2013 Waterschadeschatter from Nelen & Schuurmans and Deltares [1] in the Tygron Platform. Based on the Water Overlay's calculations and its resulting estimation for impacted buildings, a consistent and indicative estimation of costs for damaged buildings due to rainfall is calculated. This indicator is useful in project in which (for example):

  • Water damage mitigation is an important aspect
  • Cost- and risk analyses of water-related calamities are done

This Excel indicator can be downloaded from the Tygron Index. Read on to find out more about the indicator's calculation method and how to set it up in your project.

Indicator Panel

Wss indicator panel.JPG

The indicator panel shows the following information per neighborhood:

  • The neighborhood name
  • The total damages per neighborhood, in euros. Based on the setting of the global WELK_SCHADEBEDRAG (see below) the displayed costs are either the averaged, maximum or minimum costs. This global can be changed to choose which costs you want to calculate and display. In the table this is visible in the row above the costs column (in the image on the right you can see that the average damage costs are displayed).

Calculation

The calculation is based on the 2013 Waterschadeschatter from Nelen & Schuurmans and Deltares.[1]. The indicator focuses solely on damage to buildings, due to rainfall. For calculating the damage to buildings, the Impacted buildings result type is used. For this result type, the IMPACT_FLOOD_THRESHOLD_M and the classification of what important or even critical buildings are, can be adjusted.

Wss function values.JPG

When importing the Excel file into the Tygron Platform, the following attributes and corresponding values will be automatically added to 136 functions in the Function Values table. The values represent the damage costs and are taken from table 4.1 of [1].
Below an overview of the attributes with a short explanation:

  • AVG_DIRECTE_SCHADE average direct costs
  • AVG_INDIRECTE_SCHADE average indirect costs
  • MAX_DIRECTE_SCHADE maximum direct costs
  • MAX_INDIRECTE_SCHADE maximum indirect costs
  • MIN_DIRECTE_SCHADE minimum direct costs
  • MIN_INDIRECTE_SCHADE minimum indirect costs
  • PRIMAIR (not yet used in this indicator)
  • SECUNDAIR (not yet used in this indicator)
  • TERTIAIR (not yet used in this indicator)

Also, the following globals will be automatically added:

  • HERSTELTIJD_IN_DAGEN this global represents the recovery time in days. According to [1], allowed values are 0, 0.25, 1, 2, 5 or 10 (days).
  • WELK_SCHADEBEDRAG this global is used to set which costs are calculated. Values that can be used are 1 (for the average damage costs), 2 (for the minimal damage costs) or 3 (for the maximum damage costs). By setting this global, the corresponding values in the function values table are used to calculate the damage costs per neighborhood.

The following formula, see also [1], is used:

The damage is the sum of direct and indirect damage:

Damage = direct damage * ydiepte * yduur * yseizoen + indirect damage per day * recovery time

For damage to buildings is in this formula especially the water depth of the flooding important (till a maximum of 15cm on floor level, which corresponds to 30cm on groundlevel).

Direct damage

  1. As a base the division in neighborhoods in the Tygron Platform is used
  2. With the global WELK_SCHADEBEDRAG the type of costs are set
  3. For every neighborhood:
    • Name of the neighborhood
    • The area of the building category corresponding with table 4.1 [1] where there is flooding (15cm or more) and classified as an important or critical building * the direct damage costs (average, maximum or minimum depending on the global WELK_SCHADEBEDRAG)
  4. Sum of these areas * ydiepte * yduur * yseizoen where:
    • Ydiepte: damage factor inundation depth. A factor of 0,5 is used
    • Yduur, Yseizoen: not important for this calculation for damage to buildings, according to the Waterschadeschatter of Nelen en Schuurmans and Deltares.[1]. Therefore a constant value of 1 is used


Indirect damage

  1. With the global HERSTELTIJD_IN_DAGEN the recovery time in days is set: either to 0, 0,25, 1, 2, 5 or 10 days
  2. For every neighborhood:
    • The area of the building category corresponding with table 4.1 [1] where there is a waterdepth of 15 cm or more and classified as an important or critical building * the indirect damage cost (average, maximum or minimum depending on the global WELK_SCHADEBEDRAG)
  3. (Sum of the areas per neighborhood) * recovery time


The total damage per neighborhood = direct damage per neighborhood + indirect damage per neighborhood

Score

This indicator does not calculate a score. Instead, it only displays the calculated total of damage costs in euros for the entire project area.

Additional configurations

For the indicator to calculate, a rainfall overlay has to be added and some small changes to the Excel file need to be done. Read below for the steps.

Add the Overlay

Read below on how to add the rainfall overlay.

How to:

  1. Select in the editor Current situation from the ribbon
  2. Hover over Overlays in the ribbon bar
  3. Select the rainfall overlay from the drop down menu
  4. Configure the water overlay by using the Water overlay wizard. In step 5 of the wizard, select at least the Impacted buildings result type and set the IMPACT_FLOOD_THRESHOLD_M on 15 cm to calculate water damage by a water level of 15 cm or above
  5. Hover over the Auto update icon and choose for Reset X queries (slower) to recalculate the Overlay.

Edit the Indicator Excel file

See the steps below how to edit and update the indicator Excel file.

How to:

  1. Using the query tool, find the ID of the Impacted Buildings result type, created in the section above.
  2. In the indicator's excel file, enter this ID in cell C12.
  3. In the indicator's excel file, select the entirety of rows 8 and 9.
  4. In excel, switch to the "Formulas" tab at the top of the excel window, and then select the option "Create from selection" (in the "defined names" block).
  5. By default, only the option for "Top row" should be selected. Select "OK".
  6. Save the file, and upload it in your project as an indicator.
  7. In your project, open the indicator panel, and click the "Install" button.
  8. Keep the indicator panel open until it reports that the install is completed.
  9. Close the indicator panel, and hover over the Auto update icon and choose for Reset to Start Values (faster).
  10. The indicator is now installed

References

  1. 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 Waterschadeschatter (WSS) Users manual ∙ found at: https://www.stowa.nl/publicaties/waterschadeschatter (last visited 2017-10-11)