Maybe I should build something down there.
Does it pass under a bank?
About a mile from my home there is a large drainage tile and basin. As very dumb kids we'd play in these tunnels. One summer we built a fort on top of the biggest cistern, then it rained one day while we were away and we came back to find a small lake and all our stuff we'd left in it, under 3 feet of water!
So, I'd pass on the building something part of the plan. LOL