HOW DO I MODEL THIS IN 3D USING SOLIDWORKS OR SKETCUP?

Hi @P.K.
SolidWorks isn't really very adept at creating a lot of jagged and disconnected objects (like those rocks). You can draw them but it will take a lot of time.
Two alternatives occur to me:
1. Make a simple drawing with the rough geometry of the fender (not the detail of the rocks) and apply one or more rock textures on top of them to give the "visual feel" of realism to the model. This won't work for you if you intend to actually use the real geometry to do some kind of validation (such as a CFD simulation to assess the efficiency of the fender and its interaction with water).
2. Create the defense in another application, such as BLENDER, which can generate multiple objects (particles that represent rocks) of various sizes and unlimited quantity on a surface (such as an embankment or basic geometry that you draw as a reference). If you really need to process this geometry in Solidworks, you could import it as surfaces of triangles.