How much water to carry on a day walk
All the water that will ever be,
is right now. National Geographic, October 1993
Water is critical for life: humans need water for all basic biological processes to happen including muscle and nerves to function. These processes are all crucial for feeling good and making good decisions on a bushwalk.
Figuring out how much water to carry starts back home in the planning and preparation stage. Water requirements increase in hot and humid conditions and when active. Part of the trip preparation process involves looking at the weather forecast, figuring out what terrain the trip involved and also dressing appropriately for the conditions.