The bridge crosses the Beaver Run which joins French Creek a little way downstream. These waterways are popular fishing spots, especially in the spring when trout season opens.
You are "fishing" for a bison tube. It is NOT in or near the water- no waders necessary! Do not try to take the fishing rig apart except to screw open the tube to sign the log.It is meant to stay together. If you lose the fish or the hook or break the fishing line, LET ME KNOW RIGHT AWAY. Fishing is not my best subject!
I encourage you to look for at least some of the geocaches along the Horseshoe Trail, east or west. In regard to the Multi-cache described above, if you read the description and hints and logs and have good woodsman's and bushwacker's skills, you can find it without coordinates.