Either a front skid plate or the rubber splash guard thing should be under the front end of your engine. If you look behind the radiator and see the ground your missing something.

Won't do much to keep water out if your fording 3 foot deep steams but it will will help keep water and dirt out of your alt.
Dielectric grease in all of your eletrical connectors will help keep it running when dunked.

Keep a can of WD40 handy if you go deep. <img src="/forums/images/graemlins/lol.gif" alt="" />