Meaning: This means that the girl is very excited to jump over the brook. She is using all of her energy to do it, and she is having a lot of fun.
Choice of Words: The girl is still the subject of the sentence, but now she is leaping instead of jumping. Leaping is a more energetic and powerful word than jumping, which suggests that the girl is really putting her all into it. The brook is a smaller body of water than a stream, so it is easier to jump over.
The young lady enthusiastically bounds over the creek
Meaning: This means that the young lady is very excited to jump over the creek. She is full of energy and is having a lot of fun.
Choice of Words: The girl is now referred to as a young lady, which is a more formal way of addressing her. Enthusiastically means that she is very excited and eager to jump over the creek. Bounds is a more playful and bouncy word than jumps or leaps, which suggests that the girl is really enjoying herself.