One section of Hyrule is a vast maze of water filled tunnels and caverns called Zora's Domain. It's water source is unknown which may lead to the belief that this is a Karst landscape and that Zora's Domain is a series of caverns created by water from hidden valleys somewhere else that disolved the rocks as it passed through.
The water inside the domain doesn't really have a clear exit either. At some point it ends up in Lake Hylia to the north as shown by items from Zora's Domain, like rupees and jars, whcih show up on the lake's bottom. This is more evidence of under ground water ways, typical in a karst landscape.
Also their are typical cave formations inside the Zora's caverns. That spike sticking out of the water in the picture above is whats known as a stalactite. It was formed when disolved rock minerals flowed in and built up on that spot to form a spire there.
