On Mac notebook computers, local snapshots are automatically enabled when you turn on Time Machine. Just like regular Time Machine backups, local snapshots are made hourly in the background.
You can disable Time Machine's local backups with the Terminal command below, however, I suggest you not disable it and just leave it alone.
This space does not in any way reduce the storage space available to you on your drive. OS X manages this space and if your drive reaches 80% full and you need the space, OS X will shrink the local backups space. So just ignore it.
If you notice when you look at your available disk space in the Finder, this backups area is not included.
If you turn TM off then back on this space will go to zero, then slowly start expanding again.