Valley
noun
The kanji and the word are exactly the same. That means they share meanings as well.
たに
Since this word is made up of a single kanji, it should use the kun'yomi reading. This happens to be the reading you learned with the kanji, too, so don't feel like you're stuck in a valley of despair or anything. Rejoice!
谷の水はきれいです。
The water in the valley is clean.
あの谷には、ナウシカという名の少女がいますよ。
There is a girl named Nausicaa in that valley.
谷の入り口はここです。
The entrance of the valley is here.