you get it in the ice cave
In the Ice Path.
get the TM surf and waterfall and youll pass it
The way you get waterfall is by trading the waterfall HM from Fire Red Version or the other Version that have waterfall HM ( you can trade with a link cable or wireless adaptor)
You can find Waterfall in the Dark Cave.
HM07 Waterfall is found on the Ice Path.
you get it in the ice cave
You find HM08 Waterfall on BF4 of the Cave of Origin
Get the HM Waterfall in the ice path then go to victory road click A on the waterfall and your pokemon will go up the waterfall.
After you beat the eighth gym you are allowed to use the HM waterfall
Feraligatr cannot learn Waterfall in Pokémon Gold and Silver, additionally it cannot be taught it via the HM.
it doesn't exist, sorry.
i think that wooper can't learn waterfall at a level.