So how did Barney get all the way out in the water like that? Well first an idiot named Blake C. Talman, was drunk and thought he'd go for a drive. While fleeing from another crash scene, Talman hit and killed a 53-year-old woman named Donna L. Chen as she was jogging with Barney. Barney, as you can see in the video, was also injured and was so spooked that he took off and when he ran out of land - started to swim. Thankfully, Barney has since been reunited with his family and is on the mend.
Sources: Youtube and ABC