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FriedFred t1_iwj7hxm wrote

This feels like something you could mitigate by changing the control regime of the dam - if you lower the “full” level, then be would be more spare capacity in the event of a big rainfall event, leading to the same risk of failure as before.


ian2121 t1_iwjdqfy wrote

That’s how flood control dams are already managed.


FriedFred t1_iwjeiaf wrote

Ah, thanks - these aren't reservoirs, they're smaller dams for flow management. Makes sense now.


Redvomit t1_iwjityt wrote

No, this affects all storages designed for extreme inflows. Arguably, smaller dams and reservoirs are less affected by this specific research (but are still affected by climate change impacts)


ian2121 t1_iwjiv56 wrote

Could be old hydro power dams or irrigation dams. Depends a bit on your climate and region. Speaking of flood control dams check out the Presa Rompepicos near Monterrey Mexico.


FriedFred t1_iwjn5wl wrote

Cor, that's a massive dam - I hadn't really appreciated that you might want to build something that big for the sake of flood management, rather than because you want to store the water for later (e.g drinking water reservoirs).

Does a structure like that aim to produce constant river flow, averaging out the wet and dry seasons? Is this sort of thing only common in places with variable climates?


ian2121 t1_iwjnwmw wrote

I’m in the PNW so l don’t know a ton about it but I believe the sole purpose of that dam is to minimize flash flood damage to the city


admiralbundy t1_iwk8e1g wrote

You can lower the full supply level to create airspace or a flood mitigation zone. This would trade off the available water supply in exchange for dam safety protection.

However, almost all dams in an extreme event are filled multiple times over by the inflow, thus making any lowering of the storage prior to the event futile.

But it is a valid point and in some dams can be useful.


Omiok t1_iwjengz wrote

Not only to change the operational levels by changing the dam crest elevation or the spillway intake level, there might be a need to adapt the spillway geometry overall or to add emergency spillways. There also may be solutions by changing the land use at the upstream catchmemt area, to increase the infiltration and reduce the direct flow. Anyway, sounds like ground for work to hydrological engineers worldwide.


Tigen13 t1_iwk7pik wrote

Insurance companies have a term "acts of god" for unusual weather events in which they don't have to pay out.

Climate change will likely bring more of these. Dams may not be able to relieve enough water in time. Or you can have a Pakistan event. 10x more rain than the historical average over an extended period of time.