The model was made using Carrara's Terrain maker and a bump map made in photoshop. You can make water in poser though. You need the high res square (from the primitives or import the object file included below if P4 doesn't have a HighRes square) and use a wave generator (a form of magnet deformer).

See the picture links below for the exact values and locations of the options.

1 load the High res square and add a Wave Deformer (pic 1)

2 set the Wave prop values to those in the screen capture (they are a good place to start). You can try increasing or decreasing the values to see what the effect of each one is. I recomend small amounts + or - .05 at a time. (pic 2)

3 Adjust the Wave zone prop to cover a area larger then the water (see pic 3 for values).

As for the water texture map blotches of white and blue work well. If you have photoshop (5 or later) create a new document about 2000x2000 and wet the background to white (not transparent) on the tool palet set one square to white or very pale blue and the other to a nice medium water blue. Then use, filter-Render-Clouds then Filter-Distort-Glass. This will give you a testure that works well for water, in both cases use the default values (Pic4). Back in poser apply the texture to the Highres square and set the transparency to between .6 (very clear water) and .8 (cloudy water). Thats it, you should have a good looking water prop that you can even animate by moving the Wave prop or just changing the values.

"Water1"
"Water 2"
"Water3"
"Water4"

If you don't have photoshop feel free to use the attached texture (Water4). By playing with the wave generator you will learn to understand it better. It's one of those things that the more you play with it the easier it is to understand. You can increase the complexity of the water.

I did the screen captures in Poser 6 so some of it will look different in Poser 4 but the idea is the same. There may be a couple of options in the captures that 4 doesn't have (not sure on this) if so just ignore them. I also don't know if poser 4 has a highres square so here is one you can download in object format that I whiped up in Carrara. just import it into poser with all import options turned off and it will load right where ya need it :-)

"WaterProp"