Understanding R2D's Hurricane Modeling: Can It Handle Flooding and Storm Surge?

[pahuy]

Hello,

I'm in the process of developing a case study on historical hurricanes for my research project. This study aims to break down hurricane events into three distinct hazards: strong winds, storm surge, and flooding. In my exploration of the R2D tool, I found that it can generate features like hurricane tracks, raster files, and hurricane grids. However, it does not currently offer the option to create separate hazard maps for strong winds, storm surges, and flooding.

Upon reviewing the provided examples (Sections 4.6 and 4.7), I observed that Example 4.6 delves into the effects of water. A closer look suggests that the primary difference between the two examples resides in their asset definitions. Specifically, Example 4.6 includes variables like flood zones and foundation types in the asset information, which I assume are used to assess the impact of water.

To more comprehensively model the effects of both flooding and storm surge in R2D, I believe there are three viable approaches:
-   Revise the asset definition to incorporate parameters related to flooding and storm surges.
-   Add user-defined fragility functions (which I think now is not feasible since I need to incorporate storm surge and flood hazard first).
-   Add specialized modules to R2D for flood and storm surge modeling.
Could you please confirm if my understanding is correct?

Thanks,
Huy

[jyzhao]

Hello Huy,

Besides different asset information, example 4.6 also has an additional Intensity Measure (IM), which is Inundation Height, i.e., PIH, in the input_data. This IM is later used in the HAZUS-style flood damage and loss assessment. By editing the asset information, IM, and auto_population script (e.g., auto_HU_NJ.py in Example 4.6), strong winds and flooding can be analyzed separately.

As far as I know, HAZUS does not have damage and loss models for storm surges. As a result, R2D does not have a built-in DL model for storm surges. You can add your costume DL by defining customized fragility functions. An example of defining customized fragility functions can be found in example 4.8.

"Specialized modules" for flood and storm surge modeling are not needed unless custom engineering demand parameters (i.e., different from using IMs as EDP in Example 4.6 & 4.7) are desired. Incorporating custom EDP is currently not supported in R2D and is under development.

Hope this helps to clarify.

Best,

Jinyan

[pahuy]

Thanks Jinyan,

Your clarification is sure to help. I will return if I have any additional questions.

Huy

[adamzs]

Hi Huy,

Let me add a slight clarification to the detailed response Jinyan provided: Although Hazus does not have storm-surge specific fragility and loss functions, the hurricane technical manual describes that the functions developed for flood should be used for this purpose. We have those available and they are applied in the wind+storm surge example.
In other words, as long as you have a Peak Inundation Height intensity measure available, you can use the auto-population script in the example to apply the Hazus fragilities and estimate damage and losses from storm surge.

Another relevant detail is the combination of wind and inundation losses. It is important to combine these without double counting. We use the combination methodology described in the Hazus Hurricane Technical Manual and this process is automatically performed in the background.

I hope this helps, let me know if you have any questions.

Adam