Hate to be the bearer of bad news, but the small bowel (small intestines) don't easily absorb water. The bowel walls are a semi-permeable membrane and the primary function of the small bowel is to pull water already in your body into your small bowel to dilute high concentrations of glucose (sugar) in what you just ate. Thought about in simpler terms the small bowels draw water FROM your body into your bowels to aid in disgestion and your large intestine sucks it back out when you're done with it. So without a large intestine you have to be very careful what you eat and drink or your small bowel will suck you dry and dehydrate you pretty quickly. And you'll find that your thirst will be your worst enemy because the more you drink the more you'll dehydrate. When talking about what you drink and liquid absorption of the small bowel fluids are grouped into 3 classes. These are Hypertonic, Isotonic, and Hypotonic. Think of them like the 3 bears. Hyper is too high in glucose and causes your small bowel to dump water like crazy to dilute. Iso is the middle bear, meaning just right, and Hypotonic has too little glucose, but can still be a problem. I suggest you read Carol's article on this, here's the link;
That semi-permeable bowel wall of the small intestine only lets pass thru liquids with the correct balance of sodium (salt) and glucose (sugar). Water molecules are attached to those guys so the only water your small bowel will absorb comes from liquids with the correct proportion of those guys. So the bottom line is you need to trick the small bowel to draw water into it by drinking liquids that have the correct levels of sodium and glucose in them. You'll see she talks about Oral Rehydration Solutions. The ones you buy taste like pure shit. Ok, bad choice of words. They taste like drinking salt water and sugar. I've spent a lot of time making ORS that tastes good, but you do have to train your taste buds a little bit to like them. Sort of like switching from Diet Coke to Diet Pepsi. At first the other will taste gross, but over time you won't even like the previous one. The other thing no one really talks about is that for the Isontonic fluids (the ones that are just right) there's actually a gradient for the ratio and not one specific value. So think of it as the ratio they state as being optimal, but you can be a little one either side of that ratio and it still works. No one really defines the gradient, but it exists. So for instance if you make up an ORS to drink and you add ice. Well, once the ice starts to melt you now have a liquid moving quickly toward being Hypotonic. The gradient allows for some ice to melt and the bowels will still absorb, just not as efficiently. But once a lot of the ice melts you'll be too Hypo and it won't work. Finding the actual gradient boundaries is really hard.
For me I hit McDonalds every morning and get a 32 oz cup. I put a splash of regular Coke in it (for the 25g/L of Glucose I need), then add 2 salt packets (for the sodium) and then fill the rest with Diet Coke. Ends up being a little sweet, but McD's doesn't have seltzer to add. At home I use a bunch of seltzer in the mix to reduce the sweetness. My body sucks it up and I never have an issue with hydration. And I only have about 3.5 ft of small bowel left and my colon is disconnected. So if I can stay hydrated.....anybody can.
Timing is also a consideration that Carol doesn't talk about, but that might affect me more than you since you have more small bowel than I do. If your bowels are alway full of food that's being digested it's hard for the liquid to displace the food and be absorbed. The food also changes the glucose/sodium balance so it's a crapshoot as to what the ratio is when you eat. For me I can drink a 32 oz bottle of my ORS at 2:30am (when my bowels are empty) and none of it will come out in my bag. It all gets absorbed. That's a lot of liquid for a 3 ft peice of garden hose to absorb. But being short gutted I need my bowels absorbing food most of the time or I'll shrivel up and die, so timing is important to me.......probably not to you. There's probably way more info on this subject than you want to hear, so if your head starts spinning just shout back and I can break it down and summarize it for you. But don't take this subject lightly or you'll find yourself severly dehydrated.