There were horse mounted recon during the Rhodesian war. Not quite lighthorsemen/dragoons, but horse mounted recce guys who could cover more ground than footmobile. The Feraday and Sons chest rig was popular among them and their sustainment gear was carries in saddlebags.
I'm not 100% sure if I'm understanding here, I agree anyone had better plan on having a good way of collecting and purifying water. Which I do have covered in a robust, simple and long term ability to purify, and boil if needed in the canteen.
