Turtles take ALOT of work & care for to do it properly. So do yourself some research & really plan it out beofre you decide to do this. I know you have probably made up your mind in keeping it if u r on here askin so u will not listen to people saying to let it go. It would be best for you to put it back where you found it. That is its environment & it is where it knows how to live. BUT if u are keeping it again do what is right for it. Since it is wild you will have to make it a wild habitat. It is not a store bought, tank bred & raised animal. You should think of making it a pond. You 1st need atleast a gallon per inch of turtle, if buiding pond, @100 gallon is the smallest you should go, it needs room to grow & roam. ponds need to be ENCLOSED, a small little fence around it or it will escape. The pond needs pond plants for it to seek shelter as well as feed on. Floating plants, water lettuce, hyacinths, anacharis, or hornwort--all things they like to eat. You can put some fish in it too. For food--rosie minnows are the best, least fatty, most nutritious, a few small goldfish too--itll eat them, not nutritious, but likes them. maybe even buy some tadpoles & snails--they eat those too. itll eat worms, crickets. It needs to eat in water, it cant digest food outside of water. Your pond will need a filter, a pump, some rocks, somewhere to bask in the sun--they love the sun, a big rock or you can buy a turtle dock. You need to watch the water that its not too hot not too cold, monitor it has not too much algae growing, all the right plants, some promote oxigination, some stop algae growth, others good for feeding. Then depending where you live u may have to move them in for winter if u dont plan on them hibernating. so another whole set up for the winter, then you need heating lamps, uva/uvb bulbs they still need the sunlight--& keeping them clean! They harbor salmonella! Clean wate ris a must! So it is expensive. u need to think about that. If your ready to take on all the work, u can afford the start up costs & your in it for the long run go for it. They are beautiful fun little creatures--I really enjoy mine, but they are continuous work, as any pet. heres a few sites,
www.turtlesale.com there is a messageboard there its good, they give good info. also a pond store i buy from
www.pondmegastore.com they give good info on what each type of plants do. good luck.