We are on the Old Spanish Trail road, before there were cars. This part of the road was called "Journary of Death." This was 55 miles in the heat with no water (it took about 3 days to travel this section of the road). The tempature would reach as high as 120 degrees F, during the days. Most travelers would wait until night time, when the tempature would be in the 80's. The travelers would have to take water with them, for their livestock and themselves, many died. The traveler would see bones and dead bodies from livestock and others littering the ground as they traveled. No one took the time to bury their dead as this cost in the short supply of water that they had.
Think about it if one is to drink 64 oz to 100 oz of water each day, how much water do they need for 3 days (this is only for ONE person)? Now if you take the same amount and there are five in the family and six oxen. How much water do you need? The wagons weren't very big either.