$ sudo apt-get remove gwaterfall 

Uninstall gwaterfall including dependent package

If you would like to remove gwaterfall and it's dependent packages which are no longer needed from Ubuntu,

$ sudo apt-get remove --auto-remove gwaterfall 

Use Purging gwaterfall

If you use with purge options to gwaterfall package all the configuration and dependent packages will be removed.

$ sudo apt-get purge gwaterfall 

If you use purge options along with auto remove, will be removed everything regarding the package, It's really useful when you want to reinstall again.

$ sudo apt-get purge --auto-remove gwaterfall 

See Also,