Juturna

Not sure how accurate this is, as the website I got it from seemed a bit sketchy, but I used the info Lucille provided to fact check into Google, and Iuturna came up, under a webpage for the name Gioutoúrna. Turns out the page credits it as being a version of Latin Volturnus, an Etruscan god. Volturnus was eventually turned into Volvĕre, meaning "to turn, to roll." It also recites the story about being Juturna being the sister of Turnus, so by that Wordsmith's speculation is also probably right. It originally reminded me of Jupiter so I figured whoever made up the myth was just too lazy to think of a new name and just used a female variation of Jupiter's, but it may be an original. Either way, it's very cool.

The original spelling of Juturna is Iuturna. [noted -ed]

I believe Juturna is regarded as a fusion of the names Juno and Turnus. To expound, the nymph Juturna is the sister of Turnus, the Italian prince whom Trojan Aeneas vanquishes in The Aeneid -- both she and Juno, an implacable adversary of the Trojan people, aid Turnus in his contention with Aeneas and therefore strive to stymie the fulfillment of Aeneas's grand destiny (that is, Aeneas is destined to found the Roman civilization).

She was also the goddess of wells.