ISIS militants in Iraq have managed to gain control of a key piece of infrastructure in the country, the Mosul Dam. It’s not the first time the group has taken over a supply of water, electricity, or oil.

It’s likely they will attempt to extort Iraqis in the area, who rely on the dam for water and power. ISIS has shown a “great ability to be self-supporting and self-financing and a great ability to carry out extortion schemes,” says Tim Arango, the Baghdad Bureau Chief for the New York Times.

The worry is that ISIS could open the Mosul Dam and flood the area, as they did with the Fallujah Dam earlier this year. Arango says it will probably be difficult to retake the dam, since the structure itself is very fragile. It’s unclear if ISIS has the “capability to maintain it.”

 “A very small crack in that dam could just start the water flowing.”

Listen to the full conversation in the audio player above.