Then you need to make a mesh manually using the surface command set. You should end up with a grid where you can manually edit height references of the individual vertexes.
Do this for the near view, in the mid and/or far distance either space out the x/z position of the vertices or skip rows/columns in order to save on processing time as the far view does not need as much detail.
There are a number of ways to go about adjusting the vertice heights, for the most part it will depend upon what factors you want to influence the height. Sea strength, wind, lashing water near rocks etc, basically you'll use some kind of sin() wave of sorts, the question is what angle to give sin() and the amplitude based upon environmental factors.
Do this for the near view, in the mid and/or far distance either space out the x/z position of the vertices or skip rows/columns in order to save on processing time as the far view does not need as much detail.
There are a number of ways to go about adjusting the vertice heights, for the most part it will depend upon what factors you want to influence the height. Sea strength, wind, lashing water near rocks etc, basically you'll use some kind of sin() wave of sorts, the question is what angle to give sin() and the amplitude based upon environmental factors.