No matter how many things you manage to prepare for ahead of time, you will always need water in order to survive. A simple container with an open top can be used to save additional supplies of water for a variety of different needs. When combined with a decent water filtration system, you can manage to accumulate significant amounts of water to get you by in a crisis.
Staying above the water line!
Ka-Bar Black Kukri Machete
Cold Steel Magnum Kukri Machete (Cordura Sheath)
Big Bohica Kukhri Machete
Gerber 31-000705 Gator Machete Pro, Nylon Sheath