Urban flood risk mitigation outputs and river flooding

Software Support
1

Dear all,
I was reflecting on the Urban Flood Risk Model and in particular the relationship between urban flooding (the focus of this model) and river flooding.

Is it possible to find relationships between the otuput of this model and river flood risk? If so, which ones?

Thank you,
Antonio

2

Hi @antobaro,

While I don’t have direct experience with this sort of relationship between models, there are 2 InVEST models that look related to your question: Urban Flood Risk Mitigation and Urban Stormwater. Both of these models produce outputs that could help you understand the mitigating abilities of your urban landscapes in storm events. If you already know how runoff volumes affect the risk of your river flooding, that sounds like you might then have a direct link between the models and river flood risk.

But I unfortunately don’t have any specific suggestions about modeling that link between runoff volumes and river flood risk. I’ll see if our urban and hydrology teams have any suggestions.

James

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3

Thank you James for your reply and availability.

So the run-off has two possible consequences:

(i) it can lead to widespread flooding in urban areas, not necessarily related to river overflows (but dependent on, for example, the carrying capacity of the sewerage system)

(ii) it ultimately flows into rivers, contributing beyond a certain threshold to rivers overflow.

Is this correct?
Thank you again

4

So far the only possible link to river flooding that I have found are risk zones, created based on the return time and duration of rainfall.

image

I currently have as a design storm in the Urban Flood Risk Mitigation model set a 48h duration and 10 year return time (135mm rainfall depth) rainfall event.

So the run off produced (based on this duration and return time of the design storm) would cause a river flood classified with moderate risk to property and people.

5

Hi @antobaro sorry about the delay here.

At least as far as these 2 InVEST models are concerned, yes, these consequences sound correct to me. But I suspect there are other consequences to flooding such as disease transmission, damages to built infrastructure like roads, etc. that are not captured by InVEST. There might be other models that can help to evaluate the risks associated with these given floodwater depths for your region.

Does that help?

Given this rating system, that makes sense to me.

James

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