Genesis 13:6-7

6Now the land was not able to support them [that is, sustain all their grazing and water needs] while they lived near one another, for their possessions were too great for them to stay together.

7And there was strife and quarreling between the herdsmen of Abram’s cattle and the herdsmen of Lot’s cattle. Now the Canaanite and the Perizzite were living in the land at that same time [making grazing of the livestock difficult].