"Please take a look, this is the normal situation of natural water supply in a region."
Gongsun Bao pointed to his own hand-drawn map.
It was a large scroll of sheepskin with a piece of land depicted in ink, marked with mountains, forests, plains, and rivers.
"The main source of land water supply relies on natural rivers or lakes. Here, I'm mainly talking about rivers that pass through a part or the whole of a landmass."
He gestured on the map with his finger: "The water from the Dead Sea enters the land and settles in the soil environment, becoming drinkable. Generally speaking, the further inland and away from the Dead Sea, the purer the water, and the safer it is to drink."
"The water near the Dead Sea has certain hazards, at least for humans, as drinking it would cause various diseases or anomalies."
