why don’t dam operators dredge in the dam lake during dry spells (or times when the water levels are too low) to expand the dam’s water capacity?

Question

Because I think it’ll be nice to have more water stored

In: Engineering

Answer 1

They often do dredge the reservoirs, and sometimes when it is dry. You’ve got to figure out how to get the sediment out, and where to put that sediment. Both of those can be expensive. From what I’ve seen online, there are a ton of factors that go into making the decision of when and how to dredge — the purpose of the reservoir (flood control, recreation, hydropower, drinking water), the type of sediment, the type of dam, who owns the dam, where funding comes from, what environmental requirements there are, and so on.

I keep an eye out in the news for one reservoir near where I grew up. That one is filling up with silt a lot faster than anticipated when it was built 70 years or so ago. One reason is fires in the watershed area lead to ash and increased erosion.