I don't think Kegety's DXDLL changes the water like that (but it does do some other nice things, if your computer can handle it). Do a search on the official forums, or on news sites like OFP.info or the intel depot here, and you will easily find a link to download it.
I believe what you are seeing is the work of a replacement water pack. You know how you can get different looking skies (higher res, accurate star maps, etc)? Well, people have also made different looking water. I know the Unsung mod had released a sky and water pack, but I think their water was a muddy brown, not tropical green like that water... anyway, your best bet is to do a search on the official forums (or ofp.info) for "replacement water" or "replacement sea" or something similar. (unless someone pops in with a link for you)