They provide water and transportation. For those that flood annually, they provide minerals for the growing of food.

Thats a very important thing,If there were no rivers what would happen to the world...some importance...

Well, let's see... if there were no rivers that means either:

1: Water somehow lost its viscosity so it won't flow. Which means, considering how much of our bodies are made of water... we're all dead. Instantly.

2: The planet became flat and water covers the earth so there's nowhere for water TO flow... so we live on Waterworld and most of us are dead.

3. There isn't any water. We're all dead.

4. The entire earth's temperature dropped so low that we no longer get rain and most likely all the surface water is frozen. Most of us are dead.

So yeah... I'd say that would be a problem.

I'm open to an option 5 for an explanation for how we would possibly have no streams of water flowing from one place to another that doesn't involve all or most of humanity being dead if anyone can think of one...

Rivers play a major role in shaping the surface features of the Earth. Even apparently arid desert regions are greatly influenced by river action when periodic floodwaters surge down usually dry watercourses.

Rivers are beautiful and should be preserved. I always think of a beautiful river whenever I hear the song, "Moon River."