How to Make a River in a Terrarium?

you could just put gravel on the top, thats how I did mine. I have fish gravel thats natural browns and soft belly and I have a pewrfect river. You juast have to build the gravel around up high. I have 4-5inchs of gravel around a 2-4 inch water depth which is plenty of depth for most terrium reptiles unless they are big swimmers like fire belly toads. I have two green tree frogs and they are much happier since I did the river yesterday rather than 6 gallons of water with betta which is what I had befor. If you add one of those 7 watt flat heaters they can go under the gravel so it dosnt show keep the water at 74-80 and add plunty of moistur to the tank.