We came upon this peculiar structure during a field trip along the Monocacy River last summer.
If it hadn’t been for this nearby marker on the ground I wouldn’t have known that it was a U.S. Geological Survey gaging station.
There are no identifying numbers on the marker. After some searching at the USGS site, I found this station (USGS 01643000) that I believe is the same site. The station in the picture there looks like the station in my picture. However, when I plugged the coordinates they give in Google Earth, I ended up at a spot in the Monocacy River. I suspect the USGS coordinates were based on an old geodetic datum.