isnt it ironic wrote: If you are a good swimmer, it actually matches up more on a time basis, than a distance one - ie. a 1 hour swim workout, is like a 1 hour run. That's not to say swimming a continuous 1 hour swim, which is actually pretty f hard, but a 1 hour workout of warmup, some type of interval session and a cooldown. Your heart rate will basically be up for an hour, and you'll get a good relaxing stretching workout. If you are a terrible swimmer, it's different as swimming with poor breathing and efficiency is really quite hard. You wont lose any aerobic training by doing this, but it's definitely not same as running. good luck, maybe you can find someone in Kenyan running community, who can find yo a safe training group!
No and yes. It's not the same as running, but you should never put 1 hour running = 1 hour swimming equivalent. Yes, if done at similar or slightly higher HR for same duration, the heart gets exactly the same workout. But it's just 1 part of running performance.
Way more important are specific muscular strength and aerobic benefits.
For first, running is mostly about the calves and lower legs. Swimming doesn't do much for them. Even cycling is mostly using the glutes and quads and unfortunately not the calves, otherwise cyclists would be much better runners.
For second, mitochondria are built in specific places. You need to stress your lower legs by running to elicit adaptions in the amount and size of mitochondria. With swimming you also build them, but in the wrong places (similar to muscles in upper body).
If you want to be a better runner, you need to run. Gwen Jorgensen had to realize that when despite having an extremely high VO2MAX and threshold, she didn't get the running performances that her lab tests suggested. Armstrong also didn't exactly set the marathon world on fire when he came, and he was doped and did insane amounts of cardiovascular training his whole life.
You can't make up with insane amounts of cross-training for a like of specific running training. It even takes away from the running if you use up your precious carbohydrate stores in other activities, or even worse, get sore from doing too much.
I think cross-training has tremendous benefits for new athletes, general health and is important for people who are injured, but for a healthy runner on your relatively high level I would not try to substitute running time with it. Won't work.
Cancel your trip, or change it to an altitude camp in Iten is the best I can recommend you if keeping your level of running is really that important to you.