Out at a place built by the Civilian Conservation Corps back in 1935/36. Found this while walking around. I think this was used for surveying changes to the land around where I am, as this area was dammed in the 1930s.
I've been searching for something specific to these but I think due to their age it might be lost to time.
Found a old paper from 1968, University of Missouri College of Agriculture that mentions these survey markers being used to compute sediment levels in small reservoirs to predict loss of capacity, actual volume of water in a reservoir etc.
If I'm reading this right, this is one of a series of markers placed some arbitrary distance apart and across from each other, allowing topographical maps, accurate measurement of water levels and depth. Apparently cables were strung across the reservoir, pulled very taut, and then fathometers were used in addition to other surveying equipment.
Pretty neat if you like to nerd out on it.
https://www.ars.usda.gov/ARSUserFiles/50701000/cswq-t6160-rausch.pdf
That’s pretty cool, great find! Did you just find it in a dry riverbed?
I made another post about a building made by the CCC back in the mid 1930s, and this particular marker is at the top of a stair landing behind that building driven down into the surrounding rock.
There is another one I know of, sort of on the other side of a relatively large cove I was on earlier. Im not sure if these two particular ones are a pair, or are related to each other somehow.