I'm a collegiate XC runner, and as the summer gets going we begin to progress into the 18-22 mile long run territory. I know on these boards the concept of bringing fuel is taboo (ala Hobby Jogger) but if I'm out there in 80 degree heat (south) for 2+ hours, is it worth bringing something to eat or drink? Just something small?
I would encourage it myself. Any time after 90min, I feel like it is reasonable to begin fueling. I would do it not to just to get energy but to prevent muscle cannibalization.
You'll need to experiment with the different refueling options. Do a little research into when to take the gu/gel stuff.
As for water, it's a good idea to plan runs around known water sources. Don't think of hydration solely in the context of your runs. Think of it as something to do as a part of your daily life.
I'd think it an absolute necessity to have water and probably food or at least drinkable nutrition on runs of that length.
In some contexts, getting dehydrated may be a good thing:
http://www.runnersworld.com/race-training/heat-stress-plasma-volume-and-the-benefits-of-dehydration
"One of the key signals that tells your body to adapt may be dehydration. So if you do the heat acclimation but are super-careful to stay hydrated, you miss out on the benefits. In the New Zealand study, the athletes were allowed 100 mL of water during the 90-minute bouts -- enough to stave of the feeling of being super-dehydrated, but not enough to stay hydrated. The benchmark some athletes are using: if you're not at least 2% dehydrated, you drank too much; 3% is good; 4% is too much."
But in general, arranging to get some water during a 22-mile long run in the southern summer sounds like a pretty good idea! Maybe a gel too, though that's more important for marathoners who need to adapt to ingesting carbs during the race.
Don't worry about what people think. If you need Gu, take it. I actually bring Gu on a good number of my runs (even if they're only 9 or 10 miles) because when my blood sugar gets low I feel like crap! I always try to take one on long runs, as well. Stop for water when you need it (or it's available). Plus, it'll be good practice for your post-collegiate marathoning when you have to take gel and water.
And again, don't base your training on what other people (especially people on this board) think, but instead on what works best for you. It's worked for me and countless others.
100% agree that runs > 90m you absolutely need water and some fuel. certainly water. to be a hardass and suffer w/o it is foolish - you won't be training as efficiently. my own strategy, if i know i'm running >90m, is to take a gel at 60m and maybe another 30-45m later depending how i'm feeling. if you know you're running by water fountains, you're fine for water. i bring water on a belt and drink it whenever i feel like it b/c i cant get to many fountains. on scorching days, i refill my bottles even.
my LR is 18-20 nearly every weekend. i carry a gel and take anywhere from 10 to 12mi in and hold an 8 ounce water bottle that i start taking at an hour.