After reading about making roads with caulk, I decided that I would try doing so myself. And if roads could be made then so could streams and rivers. I have some commercial latex roads that I bought a while back and while they are good none of the commercial rivers were what I wanted. Usually they were too wide and too regular in width. The caulk that I used is made by DAP and is available in several different colors. I decided to try the lighter brown TAN color.
PaperTerrain 6mm stone bridge set. They have two different bridge sets and they are available in a couple of different colors. One set is sectional lengths that can be used to create bridges of different lengths and the other has arched bridges in three different lengths and a pontoon bridge. After painting I used some scissors to trim the ends and to cut the ones with multiple bends into shorter sections.