The tables above are generalizations. "Your mileage may vary" But the numbers to me do not look like extended effort numbers, but huddle and try to remain conscious numbers. Swimming results is lower numbers due to fresh cold water passing the sides of your torso and groin.
I suggest you do a controlled experiment.
In a public pool swim laps equal to the width of the river times some safety factor. I would suggest 2. Tow your gear in a dry bag. Record your time.
Do this with a line attached, a friend on shore at the other end of the line, and suitable warm car or fire nearby.
Start well upstream of your parking point, unless you are a very strong swimmer.
Swim in the river parallel to the shore for a time equal to experiment 1.
Get out, open your drybag, dress, and walk two miles.
My suspicion is that you will find that it's not a good idea.
At summer camp we had a pair of twins that could do a mile swimming in 22 minutes, which implies 1000 feet in under 5. They were skinny like rakes. They were also state champions.
Bronze medallion, a common standard for swimming for supervising water related programs requires 500 yards in 15 minutes. By extension that is a mile is 50 minutes or just over a mile an hour. You are going to be in a stream that you say has a significantly faster flow than this. Which means even given laminar flow, you would go downstream about 2.5 times the width -- half a mile -- while crossing 1000 feet, assuming that you kept at right angles to the shore.
Me: I would consider doing this as a bet with a safety boat during the summer when the water temps are above 21 C (70 F) as I know from experience I can spend an hour in such water and only be very cold. I would not attempt it in winter except to escape a pack of Zombies.
I had a group of kids in voyageur canoes on the Athabasca River in September. The week before had been cool and wet, and the rain on the Athabasca icefield raised the river to flood levels. The glacier only being about 60 km upstream chilled the river to somewhere between 3 and 5 degrees C.
Partway through the first day my canoe dumped in a class I rapid.
Another canoe got a line to us, and attempted to tow us to shore. Everytime they would get into slower water we would pass them and drag them out. Finally, with a doubled line and them going the full length downstream before attempting to get to shore we were successful.
All the kids still had enough coordination and strength to hold on to the gunwale throughout this, but we were in the water for about half an hour.
The third canoe in the group went to shore and started a fire once it was clear this attempt would work. We got the kids to walk down to the fire, and got everyone out of cold wet clothes. This was not trivial. Fingers were cold enough that we couldn't feel the buttons or zipper tabs. had a hard time gripping fabric.
One thin boy was cold enough to be irrational. we had to sit him on a log and one person stood behind him with hands on his shoulders to keep him from walking into the fire.
Point of this story: These were kids who moved minimally while in cold water, were wearing wool mackinaws or sweaters, were in water several degrees warmer than your winter river will be. Once on shore they were barely functional.
You still have to dress yourself on the far side of the river. Your fingers won't do what you tell them. Your feet will be numb. You won't be able to feel what you are walking on, nor feel injury to your feet.
Things like this take preparation. If you seriously want to do this, try it in summer first. The first time you do it, do it with a life jacket on. My experience with the North Saskatchewan, a river with similar current, but narrower width is there is significant turbulence that will pull you down at unexpected moments.
- Canoe. Keep a cheap canoe at work. For this use a coleman pipe frame canoe is fine.
- Inflatable boat. Likely more expensive than the canoe, and you can't count on it being intact after years of storage.
In either of these cases, practicing is essential. You need to be reasonably proficient with using them in normal temps to have a prayer of using them under adverse circumstances.
- Bicycle. A bike can get through when cars are jammed up. A 14 mile detour = 28 miles = 2+ hours. Even if you have to go 2 bridges down, you will get home in about 1/3 the time it would take to walk, certainly within 24 hours.
- Moped. Bike with a tiny engine to augment your efforts. Call it 1/2 to 2/3 the time of a bike.
- Small scooter. The ones you see all over the orient used as commuter vehicles. Faster than a moped, and a lot less effort.
Again: Practice. Commute at least once a month this way so you can find out it's and your limits. What's it like biking in a cold winter rain?
A comment points out that earthquakes severe enough to take down bridges may also take out sewer lines. I've no idea how fast the river would become contaminated. With a 2.5 mph flow, I would expect it to be fairly dilute, unless you have extensive civilization upstream.