Has anyone done this before? I have rafted before, just not as a T1 and not wearing an Omnipod. I'm trying to figure out where to wear it, and if I should also wear a wetsuit to secure it. Any thoughts?
Sports tape. The stretchy sticks to itself bandage stuff. I forget what the real name of it is. I'd wrap that pod up as much as I could :)
I agree with Scott...waterproof sportstape. I've done it 5 times in the past and had a blast...good luck and have fun! BTW, I wore the pod on my arm so I could see it at all times.
I guess I was worried the arm wouldn't be a good place due to how much you have to use your arms. I'll use skin tac to make sure it has a good hold. I'm gonna wear my sensor too. Now I just have to figure out how to carry my meter and cgm monitor along and keep them dry...
I haven't gone white water rafting, but I did a lot of lake swimming and jumped off a rope swing (about a 6 foot drop into water from letting go) A LOT this summer. I had a rash guard/Sun shirt on and that was it. The pod stayed secure on the back of my arm no problem.
You can get water proof bags at any outdoor supply store, or maybe even a ziploc would do?
I did it a month ago and didn't have any problems. Like was mentioned, just throw some waterproof tape on it if you are worried. Ask the rafting company if you can throw some spare insulin in their dry cases, and if it falls off, you have backup.
I don't white water raft, but I sea doo quite a bit. This waterproof case (the Pelican 1050) holds my iphone 5, tabs and my pdm with testing equipment. amazon and I wear a spibelt with my Dexcom in a plastic belt. Amazon When I fly, I put them both on my waist...in a case that I found in a ranch store. 
Haven't had any issues with adhesion during water activities in general. I kayaked once while wearing a Dexcom sensor and Opsite took care of any adhesion issues I might have had. I did wear a wetsuit and my feeling is that the wetsuit did help keep the sensor in place. I imagine it would do the same for the newer pods.
I kept all my supplies in a Drypak I picked up at REI. I carried the Drypak in a good ol' fashioned fannypack.
I would definitely not trust a ziploc bag for waterproofing.
The most likely thing to detach the Omnipod is someone jabbing you with an oar or just grabbing you. A wet suit will prevent this detaching the Omnipod, but do you really want to wear a wet suit? At this time of year in the northern hemisphere even a 1mm shorty is likely to be unbearably hot. Apart from that nothing will prevent a careless fellow rafter pulling the pod off.
I'd recommend the lower back sites - they're the least likely place to get grabbed. I've never had any problems with my normal sites - lower back, upper arms - but I've yet to raft anything serious with the pod. (I've just been down the Rogue about Grants Pass - pretty much just minor riffles, class 1, maybe class 2 in one place.)
Falling, or jumping, into the water won't be a problem; the adhesive holds well enough for dives/jumps from 6ft, I haven't tried anything higher, but I can't imagine you would end up jumping more than 6ft into the water.
You might want to suspend or at least reduce your basal insulin if you are going to be hitting class 4, or maybe even class 3. I've only ever been through a class 4 once (Dragon's Tooth on the Klamath) and that was on MDI. I had to rely on intuition and emergency food (hard candy and dried fruit) because I didn't have any way to test at the time. I guess if you are rafting class 4 or above you want the pod on the front of your abdomen - that's the only place which will be protected if you end up in the water.
Get a *small* dry bag. I have a "Seal Line" 10l dry bag "See Bag 10L". I use this to protect all my stuff when scuba diving from a boat. It works really well even on a raft-size speed boat, in fact you might find a smaller size adequate. I haven't tried this but you either need to tie it to the boat (probably best) or roll it up with enough air inside so it floats.
Since you will have the PDM with you (I don't carry it for scuba because pretty much all dives are too deep) you will benefit from one of the flexible bags/cases made for cellphones. Put the PDM inside one and you can operate it from the raft - the only thing you can't do without opening the case/bag is test.
These are only half-tried suggestions. I've worn a pod under a wet suit while scuba diving really shallow dives and it works great. I've used the 10l dry bag on seven boat dives in different conditions now with good results. I've swum, snorkeled/free-dived, jumped off a boat and class-1 rafted with a pod on (the old pods) and not had a single problem.
I used a dry bag. I road in the medic’s raft and he just put it in the raft’s larger strapped in dry bag. No problems with the pod or cgm. It was a 27 mile marathon of up to class V+. Bloodsugars in check all day with my normal basal. I didn’t wear a wetsuit. Just running pants and a long sleeve running shirt. I used skin tac with my cgm and pod and wore them both on my arms.