Limestone streams

Limestone is an existing idea for a new block, but I think this might be a legitimate reason to add it(and it is fairly easy to add).

I believe Limestone should be added in the water caves shown in the caves and cliffs trailer as a sort of rock under a waterfall. What I mean by this is that in the caves should have holes in the wall where streams come out, and Limestone should be under these streams to make the water flow faster. There might be rivers or streams in the caves that just sweep away any player that jumps in it. This gives the use for limestone, it makes water above it flow faster based on how much limestone is below it. This has a lot of uses, like making actual waterslides and crashing waterfalls.