The main reason civilizations developed near river valleys is for the water supply. In other areas people would have to depend on rainfall, which could be inadequate at times. Near the rivers, however, there was a steady supply of water. Of course, at times there was too much water, during the floods. But this wasn't as much of a problem after they learned to control and use the floods to their advantage.
With a steady supply of water, they were able to grow two or more crops a year. This led to a food surplus, which made civilization possible.
As you can see, the water in river valleys played a major role in the development of early civilization.