I'm really surprised that there isn't more response to this question, but since I found it intriguing and I've been working on a quadcopter with capabilities similar to your requirements (except for the 100 km/hr speed) I'll help you…"
Waterproofing drones is possible, though I don't know how feasible it is. Check out Liquipel.com and this video of DSLR pros dunking their DJI Phantom. https://www.youtube.com/watch?v=h3pU0XKQZt4 "