This is a quick and easy tutorial on how to make rivers in photoshop that taper from small at the source to large at the destination. Its really easy actually.

I'll be showing you how to do it in Photoshop CS3, but I believe the technique will work in CS2 as well...Not sure about previous versions.

You start by creating a new path and creating the points of the river on that path.

1) Click on the Paths tab
2) Click Create New Path
3) Click the Pen Tool
4) Draw points to make the path of the river.

Click image for larger version.  Name: tapered rivers_step1.jpg  Views: 1727  Size: 520.0 KB  ID: 5828

It is important to START the path at the destination or mouth of the river...this is the point that will be the widest. The reason you create a new path is because if you just use the pen tool you'll be creating a shape, which will automatically create a shape layer and fill it...rivers are paths not shapes.

Next step is to use the Convert Pen Tool to turn the points of the river into bezier curves since the river shouldn't really be blocky. Use the photoshop help to learn how to use the Convert Pen Tool...but its basically click and drag on a point to drag the bezier handles out and make a curve. hold down ctrl to move the point.

Click image for larger version.  Name: tapered rivers_step2.jpg  Views: 1434  Size: 510.9 KB  ID: 5829

Now that you have a river path, you need to switch to the paintbrush tool. Bring up the brush options and select a brush size that will represent the width of the mouth of your river. I chose a size 12 brush here.

Click image for larger version.  Name: tapered rivers_step3.jpg  Views: 1340  Size: 487.9 KB  ID: 5830

Then you want to click on shape dynamics and where usually the pen pressure controls the size, you want to change the dropdown to "fade".

1) Click shape dynamics
2) Change control to Fade
3) Set a fade distance (in pixels for length of fade, may need to experiment)
4) Click Stroke Path to create the tapered river.

Click image for larger version.  Name: tapered rivers_step4.jpg  Views: 1845  Size: 494.3 KB  ID: 5831

If the fade length was too short or too long, press ctrl-z and change the fade length and then stroke the path again.

An interesting side note, if you prefer to freehand draw the tapered river, you can JUST go to shape dynamics and change the control to fade, set a fade length, and then use your mouse or drawing tablet to draw a line that will progressively get smaller as you draw...just keep drawing until the line fades out. Its a neat little trick.