As an addendum to the article that was posted:
I've made a few water pieces for war-gaming purposes. If you're creating a body of water that is still (fountain, calm lake, etc.); it's possible to get good effects quickly and easy. I always use clear/un-tinted resin. Instead of adding color to the resin itself, I pre-paint the "pool's" bottom. Using pictures from a nature book, replicate the bottom of the surface to look like you want. Remember: a sandy bottom of a lake is not going to look Afrika Korps tan. It usually looks greenish brown due to light reflection/refraction.
After paiting the floor of the pool, place some pepples, stones, the tar-coated pylons for your dock, some small plastic plants etc. (If you can, insert the plants at a slight angle to represent under currents.) Slowly pour in your resin to the desired depth. After it cures, you will be looking down into a small slice of underwater eden. If you really want to be meticulous about the detail, wait until the resin starts to gel and then carefully insert small reeds/grasses on the shoreline. (If you're doing a fen or marsh, build the whole thing, carving shallow channels into which the water/resin will lay. Plant a lot of flora and then add the resin.)
I've also heard (but never try) of someone who adds a second coat of clear resin (about 1/8-1/4 inch thick). This supposedly creates a hard edge in the resin's depth which forces light to blend, distorting the view.
Just some added thoughts, especially as people contemplate the next campaign.