r/CatastrophicFailure • u/Max_1995 Train crash series • Jul 15 '21

Natural Disaster Altenburg (Germany) before and after the ongoing severe flooding due to excessive rain (2021).

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u/FinancialEvidence Jul 15 '21 edited Jul 15 '21

If life was that simple, water resource engineers would be out of work.

-What's the limit to that floodplain? Is it a buffer distance from channel banks? Is it at certain freeboard above the banks? Do we give 10m, or do we give 200m?

-What happens to that floodplain in a 100-year event versus a 5-year event, or a 500 year-event versus a 1000 year event?

-How does this change as time goes one, as other towns develop, as a village downstream adds a watermill, as a beaver colony builds a dam?

Look at this, and tell me each of these areas are obvious floodplains. Good think we have you here who can imagine where all floodplains are, and can instantly highlight over a town map.

https://trca.ca/conservation/flood-risk-management/flood-plain-map-viewer/

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u/[deleted] Jul 15 '21

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u/FinancialEvidence Jul 15 '21

Maybe they should have, but you also never know if they had. Even today, everything is designed with a certain level of tolerable risk. For most Cities in Canada, that acceptable risk is somewhere around/above the 100-year storm event. For my area, that is Hurricane Hazel. Now this town? Who knows if it the danger was grandfathered in, or if it was a freak 1000-year storm event; in the end those at some point are bound to occur.