Method for evaluating flood plain risks

• US 20040199410A1
• Filed: 01/07/2004
• Published: 10/07/2004
• Est. Priority Date: 01/07/2003
• Status: Active Grant

• Current Assignee: Swiss Reinsurance Company
• Original Assignee: Swiss Reinsurance Company
• Inventors: Menzinger, Ivo, Mehlhorn, Jens, Feyen, Hans
• Granted Patent: US 7,627,491 B2
• Time in Patent Office: Days
• US Class Current: 705/4
• CPC Class Codes: G06Q 10/10 Office automation; Time management
• CPC Class Codes: G06Q 40/08 Insurance
• CPC Class Codes: Y02A 10/40 Controlling or monitoring, e.g. of flood or hurricane; Forecasting, e.g. risk assessment or mapping
• CPC Class Codes: Y02A 90/10 Information and communication technologies [ICT] supporting adaptation to climate change, e.g. for weather forecasting or climate simulation

Abstract

A method for evaluating risks associated with flooding in a geographical region comprises the steps of defining the region, dividing the region into a plurality of grid cells, identifying data relating to characteristics of the region within the cells, determining a probability of occurrence of a flood related event in a selected grid cell using the identified data, and determining an insurance premium for the risk. Certain embodiments are implemented using a computer, and involve reference to an alternative source of information regarding the occurrence of flood-related events in a geographical region. In one embodiment, a model is developed and calibrated by reference to data from a first geographic region, and subsequently used to determine the probability of occurrence of a flood event in a second region.

Claims

1. A method of evaluating risks associated with flooding in a geographical region, comprising the steps of:

a) defining a geographical region;

b) dividing the geographical region into a plurality of grid cells;

c) identifying data relating to characteristics of the region within the plurality of grid cells;

d) determining, using the identified data, a probability of occurrence of a flood-related event in a selected grid cell in a defined recurrence interval; and

e) using the results of step d, determining an insurance premium for a risk located within a portion of the geographical region that includes the selected grid cell.

2. A method according to claim 1, wherein said data relating to characteristics of the region within each grid cell includes at least one of a horizontal distance from a nearest river, a vertical distance from said river and an area.

3. A method according to claim 2, wherein said area is a catchment area adjacent said river.

4. A method according to claim 1, wherein said defined recurrence interval is defined in years and falls between 50 and 500 years.

5. A method according to claim 1, wherein said defined recurrence interval is 100 years.

6. A method according to claim 1, wherein said step of determining, using the inputted data, a probability of occurrence of a flood-related event in each grid cell in a defined recurrence interval further comprises the additional step of determining a probability according to an equation having the general form:

logit(p)=b₀+b₁VDIST+b₂HDIST+b₃AREA

where;

p=probability that a grid cell is flooded in the defined recurrence interval

VDIST=vertical distance of each grid cell to relevant river grid cell

HDIST=horizontal distance of grid cell to relevant river grid cell

AREA=catchment area at relevant river grid cell.

7. A method according to claim 6, wherein each grid cell is considered to be flooded in the defined recurrence interval if p is greater than a predefined threshold value.

8. A method according to claim 1, further comprising the step of classifying the geographical region according to climate.

9. A method according to claim 8, wherein the geographical region is classified as humid or semi-arid.

10. A computer method of evaluating risks associated with flooding, comprising the steps of:

a) defining a first geographical region;

b) inputting data relating to the first geographical region;

c) developing a model to determine a probability of recurrence of flood-related events in the first geographical region for a defined recurrence interval;

d) calibrating the model by reference to an alternative source of information regarding the occurrence of flood-related events in the first geographical region;

e) defining a second geographical region;

f) inputting data relating to the second geographical region; and

g) applying the model to determine a probability of occurrence of flood-related events in the second geographical region for the defined recurrence interval.

11. A computer method of claim 10, comprising the additional step of dividing the first and second geographical regions into a plurality of grid cells.

12. A computer method of claim 11, wherein said data relating to the first and second geographical regions includes at least one of a horizontal distance, a vertical distance and an area associated with at least some of said grid cells.

13. A computer method of claim 12, wherein said area is a catchment area of a river flowing through one of said first and second geographical regions.

14. A computer method of claim 12, wherein said horizontal distance is a horizontal distance of a respective grid cell from a river.

15. A computer method of claim 12, wherein said vertical distance is a vertical distance of a respective grid cell from a river.

16. A computer method of claim 10, wherein said defined recurrence interval is 100 years.

17. A computer method according to claim 11, wherein said model has the general form:

logit(p)=b₀+b₁VDIST+b₂HDIST+b₃AREA

where;

p=probability that a grid cell is flooded in the defined recurrence interval

VDIST=vertical distance of each grid cell to relevant river grid cell

HDIST=horizontal distance of grid cell to relevant river grid cell

AREA=catchment area at relevant river grid cell.

18. A computer method according to claim 10, further comprising the step of classifying the second geographical region according to climate.

19. A computer method according to claim 18, wherein the second geographical region is classified as humid or semi-arid.

20. A method of evaluating risks associated with flooding in a geographical region, comprising the steps of:

a) defining an area to include a catchment area of a river flowing through the region;

b) dividing at least a portion of the area into a plurality of grid cells;

c) identifying data relating to characteristics of the area within one or more of the grid cells; and

d) determining, using a model and the identified data, a probability of occurrence of a flood event in a selected grid cell for a defined recurrence interval.

21. A method according to claim 20, wherein said identified data includes at least one of a horizontal distance, a vertical distance, and an area.

22. A method according to claim 20, wherein said model is a binary response model.

23. A method according to claim 22, further comprising the step of establishing a threshold probability for use in determining whether the selected grid cell is flooded.

24. A method according to claim 23, wherein said threshold is selected to define the recurrence interval.

25. A method according to claim 24, wherein said threshold is changed to redefine the recurrence interval to a different recurrence interval.

26. A method according to claim 20, wherein said model is calibrated by reference to a second geographical region.

27. A method of evaluating risks associated with flooding in a geographical region, comprising the steps of:

a) defining an area to include a catchment area of a river flowing through the region;

b) dividing at least a portion of the area into a plurality of grid cells;

c) identifying data relating to characteristics of the area within one or more of the grid cells;

d) determining, using a model and the identified data, a probability of occurrence of a flood event in a selected grid cell for a first recurrence interval; and

e) using the results of step d, determining a probability of occurrence of a flood event in the selected grid cell for a second recurrence interval.

28. A method according to claim 27, wherein said first recurrence interval is 100 years.

29. A method according to claim 27, wherein said step of determining a probability of occurrence of a flood event in a selected grid cell for a first recurrence interval includes the step of selecting a threshold probability associated with said first recurrence interval.

30. A method according to claim 28, wherein the step of determining a probability of occurrence of a flood event in the selected grid cell for a second recurrence interval includes the step of selecting a probability threshold associated with said second recurrence interval.