Are you fed up with getting carried away by rivers when washing yourself? Are you scared of being attacked and eaten alive by hideous monsters that dwell at the bottom of those deep lakes you are swimming in? Do you crave for something more luxurious? Something more fun? Something less freezing?
Then build a jacuzzi! It won't cost you a penny, only time. But you will have plenty of that, if you are through with flying and hiking for the moment. It is fun as well. And isn't that what it is all about?
The problem of bathing is usually not the presence of monsters or low water temperatures, but rather the fast water flow. The water in itself is not too cold for bathing, but the hurry imposed by the tall mountains makes the water go fast. It makes the water feel much colder than it actually is. That is why I prefer to swim in lakes rather than rivers. Glacier rivers close to their origin being my least favourite.
Controlling the river's flow gives you the opportunity to control this coldness. You do not need any degree in civil engineering to accomplish this task, just some common sense and a delight in natural entertainment.
Make a dam in the river to raise the water level and calm the flow. Part of the dam should be at an angle of about 20 to 40 degrees to the stream. Preferably near one of the banks, since the water streams slower there. The angle in the dam will cause most of the water to flow via the (straight) main dam, but an abundant quantity will flow in a slower pace through and over the skewed side. The slower pace lessens the chill factor, while the water is happily bubbling its way down to meet you in the pool you created under de skewed side of the dam.
Pay attention to sediments! Since the water flows more calmly than usual, mud is likely to settle in your jacuzzi over time. Make small openings in the skewed part of the dam if you intend to use it for a long time and do not like mud baths. This will slightly accelerate the water flow at strategic spots, keeping the mud away. These holes do not need to be big to be effective. If the chill of the flow comes back, then you have certainly made them too big.