The Mill Stream set claims to come with 11(!) pieces. Six of those are little, snow- covered pine trees, two are end caps for the stream and only three are acually river pieces; two straights and one bend. The fork comes with 10 pieces; 6 trees, three caps and 1 fork piece. They are cast in a hard resin or plastic and are fairly heavy and durable. Each piece also has little felt pads on the bottom so they don't scratch or damage your gaming board (or whatever.) Each piece is about 1/2" thick and when all three sets are combined together they stretch just over 4 feet.
Unfortunatly it came with a snow finish. That had to go.
These shots are the pieces before painting. As you might be able to see, the banks of the river are big rocks and boulders covered in snow. There are also tree stumps and branches dotting the banks. The water portion is sculpted to look like moving water, painted and then coated with a clear coat of some kind. The coating is quite soft and sticky and picks up fingerprints easily.
All snow covered areas, tree stumps and branches were hand painted black. The rock and water areas were left as- is. The tree stumps and branches were drybrushed first with a dark brown, then a brown- grey mix and finally a light grey.
White glue was used to adhere the magic ground cover mix to all of the black painted areas. A mix of green course turf and brown fine turf were then applied sporradically on the pieces to break up the uniformity.
The project was simple enough and though it was a bit expensive than I would traditionally have spent on terrian (around $25), it is still cheaper than purchasing a river or stream specifically made for wargaming.