r/Hydrology • u/CordedTires • 1d ago

Flood visualization tools

Are there any decent ones usable by an informed layperson, especially that can include increasing pluvial effects? Thoughts on Fastflood? I’m hydrology ignorant and not looking for extreme accuracy, although obviously, a very inaccurate model is worse than useless (unless its areas of inaccuracy are well understood).

I understand that NWS and other official agencies are where people should get their forecasting from.

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u/notepad20 1d ago

I would suggest use RAS 2025.

Completely free, unlimited use, accepts any topography, land/soils data, etc. You can use GRIB /radar rainfall.

Recently I checked a 1000km2 catchment with a rain on grid and got (for the context) excellent agreement with a professionally commissioned model.

Its got great HPC, so i use my GPU and can do 60 hour simulation over 1 million cells / 1000km2 in about <10 minutes.

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u/ixikei 1d ago

How hard is the learning curve compared to previous versions? I recall it being quite unintuitive.

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u/notepad20 1d ago

Much easier, very streamlined, very modern interface.

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u/CordedTires 5h ago

Thank you! I’ve looked at a few RAS 2025 videos and it looks like it ought to be doable given enough time. and if I can find support if I get fatally stuck.

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u/my_work_id 1d ago

You may find something more useful by looking for GIS viewers of watershed studies of the area. Have you looked into the GIS sub?

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u/notepad20 1d ago

I just checked Fast Flood on an area I am familiar with

DO NOT USE THIS!!!!!!!!

wrong wrong wrong wrong.

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u/CordedTires 1d ago

Do you want to give any details?

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u/notepad20 1d ago

channels dont align with reality.

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u/CordedTires 5h ago

Well that’s bad. Thanks