Hello Colleen and welcome to JustAnswer. You're wise to research options. It's nearly impossible to hibernate the aquatic turtles in captivity. In the wild they hibernate in mud at the bottom of bodies of water that are at least three feet deep. Without ideal conditions, many turtles die during the winter. Insufficient oxygen is a common cause. Fluctuating temperatures often result in infection. Insufficient fat storage results in starvation. Undigested food in the stomach can rot and become fatal. For all these reasons, I cannot recommend attempting hibernation.
The creek probably is not a good option. Nigel is not used to water with a current, and turtles tend to prefer the water of lakes and ponds. It's also not agood idea to release captive -bred turtles into the wild, even when their species is native. Your friend's pond, however, might be an excellent option. It would provide the conditions a slider needs, but isn't the same as simply turning him loose in the wild. If you choose that option, do it now. Nigel will need time to learn to find food and to naturally prepare his body for hibernation before cooler weather develops. Mid to late august would be ideal.
The best way to rehome a turtle is through a reptile rescue group. Unfortunately, there aren't very many in Iowa. None are near Des Moines. Here are those I found:
Anderson Reptile Rescue
South Sioux City NE 68776
The two herpetological societies in Iowa have inactive web pages, so apparently are no longer active. Given all the circumstances, I think the best option would probably be your friend's pond.
If you have more questions, let me know in a REPLY. I hope Nigel will thrive in his new home.
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