Thanks, Don. Yes, the ground cover includes some real dirt. I had some work done to my gravel driveway last summer, and later scooped up some dirt around the edges (where stuff gets washed to the side during our Georgia downpours). I made sure it was fully dried, then sifted it. For an adhesive I used Stick and Stay. It's used for flooring such as tile or vinyl, and a full quart costs only $13 at the big box stores. It's fairly thick (it can be thinned slightly with water, I discovered), and I just gobbed it on with a cheap bristle brush. When the real dirt and pebbles were sprinkled on, they stuck. After it dried overnight, I locked everything down with diluted white glue, applied with a plastic eyedropper (this actually goes faster than you'd expect). I also sprinkled on some Blended Turf from Woodland Scenics, and misted everything with a spritz of gray primer from a rattle can. I try to keep things basic and inexpensive.
Here's another view of the creek, without the bridge.
