Odds are you're bridging a crick or creek, however you like to say it... And DEP and local ordinances can be very expensive folks to deal with should you go for it without their approval and disturb any waterways in any way. We had a short bridge that was being rebuilt that was held up for a couple years in part due to a small hole in the crick that fish liked to hang out in near the bridge. Somebody decided that a few trout needed a voice in the matter and that they might not find another equally pleasing hole somewhere else in the waterway...
Took a long time for some folks to find and agree on a very difficult solution of digging another new hole... add some rocks and Voila... happy fishies.