Answer :
That's survival 101. If you lived near streams you were guaranteed water. Also near streams the soil was rich was a key factor of agriculture. This was a key factor of life. If you look in todays world, most of the world population is found near bodies of water. Hope I helped. :)
because if they are next to a stream it is easier to trade since the boat is faster than horses and caravans. And the water can help grow crops and the fish is a consistent source of food
