Waterfall or water slide sort of effect

So, I have made a piece of terrain into a sort of mountain shape. It has some water, and a sort of slide-like trail etched into the mountain itself (it is the groove on the left side of the screenshot):

Work in progress terrain

I want water to flow down that trail and into the small pond (Also might put in another waterfall that leads from the pond to the ground). How would I do an effect like that? I'm new to unity and using the free version. Thanks!

There's a waterfall in the unity car tutorial, you can just pack it into a unity package and import it into your game.

http://unity3d.com/support/resources/tutorials/car-tutorial

Get the Sewer Control Room demo from the Unity site here: http://unity3d.com/support/resources/example-projects/sewercontrolroom

Have a look at their waterfall, it's precisely what you want. You need a mesh and then you need to animate the UV texture coordinates, if you pick apart that demo you will soon see how they did it. They also added some particle effects to the bottom like splashes to mask where the waterfall met the water.

You could apply a moving texture to it to make it look like its flowing down.

http://forum.unity3d.com/viewtopic.php?p=241832