[morty16]

The allies (the RAF) had fairly specialized bombs in WWII to blow dams. They would fly in from upstream and drop a bomb shaped like a barrel (picture a barrel of oil) from very low altitude. The bomb would skip along the surface as it lost momentum and then sink close to the dam wall. At a certain pressure it would blow and take advantage of the hydrostatic shock to break up the wall.

See: https://en.wikipedia.org/wiki/Operation_Chastise

[arprocter]

https://en.wikipedia.org/wiki/The_Dam_Busters_%28film%29

One of the most interesting things IMO was how they used angled lights under the planes - shone onto the surface of the reservoir to make sure they were at the correct altitude to drop the bomb (incorrect height and it wouldn't skip)

[tomjen3]

They were trying to do something completely different, with different limitations than Islamic State has. They can get a few operatives up to the dam and place the explosives, but they probably don't have access to planes or the ability to build such specialized bombs.

[JoeAltmaier]

"Bouncing Bettys"

[arprocter]

That's slang for a jumping anti-personnel mine

[JoeAltmaier]

Yes, they are also called that. I think the dam-buster bombs had the nickname first.