There is no lake at Camp Green Lake. There was once a very large lake here, the largest lake in Texas. That was over a hundred years ago. Now it is just a dry, flat wasteland. Introducing a character and setting is also a way to hook the reader.
Readers can also meet the main character head on in the beginning sentences of a book.
When he was nearly thirteen, my brother Jem got his arm badly broken at the elbow. That line is from To Kill a Mockingbird , by Harper Lee. Jane Kurtz begins her great book, The Storytellers Beads , by introducing Sahay, the main character. Sahay leaped up, tangling the thread she had been so carefully smoothing. The pounding of bare feet made her stomach chew on itself with fright.