Following are the Geographical factors impacted the development of early river valley civilizations:
Ample water resources help them to feed, bath, wash and to do so many domestication works.
River valley means fertile plains, which is so good for agriculture as they can grow lots of different varieties of crops. They didn't have to be depend upon rain.
It helped in transportation, which were used for trading and movement from one place to another.
It protects them from enemy as at a time so many person can't attack over the residing civilization.