Rocks, Gravel, Sand & Gravity; it doesn't get much easier or more natural than that.
Storage is needed, and that was included in the last video.
I live in Oregon, we have water everywhere, and I don't have to go very far for lakes, springs, streams and rivers. I live within 10 to 20-minutes from several lakes and streams. Withing an hour I can be on Mt. Hood where some of the cleanest water in the world is at my disposal; our Bull Run Reservoir is quite famous for it's purity, I'm quite lucky this way.
My truck holds 47 1/2-gallons of gas in case I need to get to the forest of Mt. Hood. I could tell you I have 100-gallons of stabilized gasoline in my garage, but that's illegal so I won't say anything about that. :-D
There is sooooo much we all need and should prepare for; and us city dwellers are in more need than most.
**************** Progressiveness Must Die Today, In Order That We May Be Free Tomorrow