PeteHski

You are likely to need around 500 ml water per hour, more if it's hot or if you sweat more than average.
I usually carry 2x 1 litre bottles on this kind of event. But sometimes I'll carry just one bottle if there are reliable feed stations where I can top up.
Nutrition is very personal. I tend to carry both energy bars and gels and consume 1x bar per hour and 2 gels per hour after half distance. I also use energy mix in my water.
Eating, drinking little and often from the start is a good tip. Also don't eat or drink anything you haven't tested on yourself beforehand on training rides.