Tutorial-Building a River

This is one of my favorite projects to date. I needed (well, wanted) a fairly realistic river that would stretch across my game table to facilitate bridge wars and break up the battlefield.

I wanted my river wide enough that it could reasonably be considered impassable except by a bridge. However, the same techniques described here could be used to create narrow streams or even wider bodies of water.

Note: I built my river in one long section because I have room to store it. Many folks make their river in several one foot sections to make it easier to store and transport.

For a video about the river I built for my table, see YouTube link

Level of Difficulty: Moderate
Time required: About 4 hours labor, plus drying time in between stages

3/16” wood, at least one side pretty smooth that is resistant to warping. Mine was a piece of chalkboard.
½” pink insulation foam
Fine sand
Kitty litter
Ground covering, (flock or static grass)
Acrylic craft paint
Clear Matte finish spray
High gloss polyurethane
PVA (white) glue
Pen or pencil

Jigsaw or bandsaw
Hotwire foam cutter
Palm sander
Tape measure or ruler
Small, cheap paintbrushes (you’re going to ruin some of these in this project)
1” foam paintbrush
Plastic cups for mixing
Medicine dropper (or anything else that you can control small amounts of water with)

Let’s Get Started!

Step 1: First, determine how long and how wide you want your river to be. My table is 3’ 6” across, so my river is exactly that length. My river measures approximately 8”-10” across at various points, measured from the outside edges of the banks. Don’t forget that your overall width must accommodate the river banks.

Step 2: With your 3/16” wood laying on a flat surface, draw the basic shape and length of your river. Remember that rivers are rarely completely straight…they have crooks and bends all along them.

Step 3: Using your jigsaw or bandsaw, carefully cut out your basic river shape.

STOP!! At this point, go ahead and check the overall size of your river by placing a few miniatures on or around it, and make sure it’s what you envisioned when you started.

Step 4: Using the palm sander, sand down the edges of the river until there is only a gradual slope from the table to the top surface of the river. This gives a more believable transition at the river’s edge, rather than having a very obvious 3’16” edge.

Step 5: BE CAREFUL! This part can be tricky! With your piece of ½ “ pink insulation foam laying on a flat surface, lay your basic wooden river UPSIDE DOWN on top of it. Carefully draw the outline of your river onto the foam.

Step 6: Using the hotwire foam cutter, cut along your lines, angling IN TOWARDS the center of your river on each side. Angling in about 45 degrees or so should do the trick, but vary the angle slightly as you go to add contour and interest to your river banks. After this step, you should have a piece of foam that is roughly the size and shape of your original piece of wood.

NOTE: There will be a lot of excess “stringy stuff” hanging from your foam left by the hotwire foam cutter. We’ll get rid of this a few steps later.

Step 7: Flip the foam over so that you can see the tops of the river banks. With the hotwire foam cutter, cut your embankments at a slightly sharper angle from the top of the bank all the way down to your river bed. Again, vary the angle as you go, gently rocking in and out with the foam cutter to create interesting contours and slopes. Follow the basic shape of your outside river edge, but experiment with moving in or out with it to give the inside river banks a slightly different profile than the outside slopes. After this step, you should have two separate river banks that you can lay on top of the wood cutout and begin to see how your river is going to look.

Step 8: I made one more pass with the hotwire foam cutter on the top of the outer slopes at this point to create a more gradual transition to the bank top. The shaping of your river banks is entirely a matter of your tastes and liking, but experiment a little bit and see what you can create. Once you’re satisfied with the shape of your river banks, give them a light sanding with a piece of medium grit sandpaper to smooth out the rough cuts and get rid of any stringy stuff left over from the hotwire foam cutter.

Step 9  With your wooden river bed on a sturdy flat surface, lay the foam river banks on top of it to ensure that the profiles more or less match up. I scooted my river banks in about 1/8” from the outside edge to make sure I didn’t have any overhang along the sides. Put down a light coating of white PVA glue where the river banks will sit, and spread it fairly thin using one of your cheap paintbrushes.

Step 10: Place your foam river banks onto the glue. If you want to add any rocks or debris in the river, now is the time to do it. Lay a flat board across the top of the river banks and weight it down so that the foam lays flat while the glue dries. LET THIS DRY THOROUGHLY FOR SEVERAL HOURS.

Step 11: Now we texture. We’re going to cover the entire inside of the river banks with fine sand and kitty litter. I recommend doing this in sections so that your glue doesn’t start drying out to quickly. Start by applying a good coat of white PVA glue to the inside of a section of your river bank, then spread it using your cheap paintbrush. Make sure that you work some of it up on top of the bank and let some pool down into the river bed here and there.

Step12: Once the first section is covered with glue, cover a few areas with random kitty litter, especially near the river’s edge. Cover the rest with your fine sand. While this starts drying, move on to another section of the river bank, repeating Steps 11 and 12 until the entire inner banks are covered. LET THIS DRY THOROUGHLY FOR SEVERAL HOURS.

Step 13: Now we’ll solidify the sand and kitty litter so that it all bonds together and will withstand the rigors of gaming. In a plastic cup, mix up a watered down PVA solution. 3 parts water to 1 part glue is about right. You want the solution pretty liquid so that it will easily flow into all the cracks and crevices. Using the medicine dropper, cover the entire inner river banks where you have sand and kitty litter. Make sure the solution gets in every nook and cranny of it. Use one of your cheap paintbrushes to spread it around if you need to. Gently tilt the river to let any excess water run off. LET THIS DRY THOROUGHLY FOR SEVERAL HOURS.

Step 14: We’re ready to start painting! The first thing we’re going to do is coat the entire piece with a thin layer of black. I mix a solution for this as well. I use about 2 parts water, 1 part black acrylic paint, and a little bit of white PVA glue mixed in so that everything is covered in a thin protective film when I’m done. Using a large brush, cover the entire river and banks with the black solution. Be sure to get the paint everywhere, including the ends of your river section. This coat serves as a primer of sorts and helps mute the colors you’ll put on next. LET THIS DRY THOROUGHLY FOR SEVERAL HOURS.

Step 15: Now to add some color! First, we’ll paint the inner banks of the river. We’re going to put on four layers of color here. Cover the entire inner bank (anything coated in sand and kitty litter) with a dark brown. If it doesn’t quite get in everywhere, that’s ok…remember, we put that black down for a reason!

Step16: You can go ahead and paint the outer banks with a dull green at this point. It really doesn’t matter what shade of green you use here as long as it’s not too bright…this will eventually be covered in flock. Be sure to paint the exposed portions of your 3/16” wood on the outer banks.

Painting the River

While the other areas begin to dry, you can start on your actual river as well. This part can be a little tricky, and may require some trial and error. The basic idea of it is that your darkest colors will be in the center of the river, and will lighten the closer you get to the water’s edge. I used a mixture of a navy blue, bright green, and a little black for my water. Most terrain builders will point out that water is not actually blue, but a greenish/brownish color. That may be, but I like seeing a fairly blue river on my game table to add some color to an otherwise green/brown landscape.

We’re also going to use what I call the “wet brush” technique. This prevents the different shades from drying out too quickly and allows you to blend the shades together a little bit. You’ll need to work quickly with this step to get everything blended before it dries.

Step 17: Dip a 1” brush into a cup of water, lightly dry it on a towel, then dip it into your original paint mixture (which should be the darkest). Paint a stripe down the center of your river. Immediately add a few drops of very light gray to your mixture and stir it up. Use your “wet brush” again and paint stripes on each side of your first darker stripe. Carefully blend your stripes together so that there is no noticeable transition. Repeat this process until you’ve reached the edges of the riverbanks.


Step 18: Now we’ll start highlighting the inner banks. We’ll use a process called drybrushing, but this first coat will be fairly heavy. Use a medium brown for this coat. Get a good coat of paint on your cheap paintbrush, but dab some of it off on a paper towel. Now, working quickly, brush across the dark brown areas of sand and kitty litter. Don’t let this layer run down into the rocks…allow your darkest brown to show through. This layer should dry within 20 minutes or so.

Step 19: Another coat on the inner banks. This time we’ll use a light khaki or tan drybrush. Get a little paint on your brush, but wipe most of it off on a paper towel. Quickly and with long strokes, run your brush across the inner banks, leaving just a little color as you go. At this point we’re not painting, we’re highlighting. This layer should dry within 10 minutes.

Step 20: Using an off-white such as Bleached Bone or Antique White, we’re going to highlight the larger rocks on the banks (kitty litter). Get a small amount of your off-white on your brush and wipe off nearly all of it on your paper towel. Then just barely rub across the highest portions of the rocks, just enough to leave a hint of white there.

!!OPTIONAL!! After all your paint is thoroughly dried, you can give the entire piece a very light coating of Matte Finish spray to seal your paint. WARNING: When I say a light coating, I mean a LIGHT coating. Use long, quick passes with your spray can from at least 12” away. Spraying too close or too long in one area will result in very undesirable results on your foam, eating it away. Your multiple layers of paint and white PVA glue will help protect it, but will not guarantee its safety from the harmful propellants in your spray can.

Step 21: It’s time to cover your outer embankments. You can cover these with flock, static grass, or whatever covering you care for. Spread a good coating of white PVA glue all along the bank, using your cheap paintbrush to fully cover the entire area. Work some of it up on top of the “dirt” or sanded area of the inner bank. You may also want to put some along the insides of the inner bank here and there, and a little along the river’s edge down by the water. Sprinkle your flock or grass over the entire area, making sure that all the glue is covered. LET THIS DRY THOROUGHLY FOR SEVERAL HOURS. Once dry, flip the river over and gently knock off any excess flock or grass that didn’t lay into the glue. Check to be sure that all areas are sufficiently covered with your greenery before moving on.

Step 22: Last step! We’re ready to create our “water”! For this we’re going to use our 1” foam brush and our High Gloss Polyurethane. Pour a little of the Polyurethane at intervals along the river bed, then spread it out using your foam brush. Work it into the edges of the river banks and over any brown areas that you put along the river bed. Also work it onto the edges of any rocks or debris you put in the middle of your river. As much as possible, use long flowing strokes going lengthwise down the river. You’ll need to do about 3 coats of this to get a good shiny layer. LET THIS DRY THOROUGHLY FOR SEVERAL HOURS in between each coat.

That’s it! At this point you should have a convincing river to proudly display and use on your battlefield!