There are many ways to create water. The movement of fluids is not recommended to generate waves. Therefore, let's turn to texture movement, as it makes it appear as if the water moves. With the BGE, we can use several different techniques, depending on the final texture mode. In this case, it only works with GLSL.
water2, as follows:
The Cloud texture is one of a list of the available procedural textures that give an overall irregularity to the material, to look like the sea.