A handy temporary water container that stores 'small' when not in use would be this:

http://www.amazon.com/Toro-29210-43-Gallon-Gardening-Spring/dp/B000E7SU3I/ref=pd_bxgy_ol_text_c

Lined with a heavy duty contractor 55 gal trash bag it would work as a temp horse watering trough (under supervision...).

I don't know how well a couple of these would work in the back of a pickup for transport unless you restricted their movement. Obviously you would need to tie the bag of water closed inside the container, too.

You would need to experiment before an actual serious 'need' arose.

The-what I would call a leaf container-could be used for gardening/yard duties in the interim.

Just an idea.....
gimpy