How Should I Recover Buried "metal Rod" Bechmarks?

[+Barthonis]

I have found some benchmarks where the description listed them as a metal rod buried so many inches under a road/sidewalk with a marked metal cover over them, but have several in my area that are just listed as a piece of rebar driven several inches below the surface of the roadway...see NK0581, NK0582 and NK0538 as examples of local rebar benchmarks in my area.

 

I'm curious how the rest of you recover these types of marks. Do you use metal detectors to locate them, just dig in the general area of the description, and what about the ones driven below the surface of the road?

 

Any help would be greatly appreciated, even if it's just a list of your general benchmark hunting tools.

 

I currently just take a 25 foot tape measurer, a small hand shovel (my wife's spare flower-gardening shovel to be exact) and my GPSr, as well as a small notepad for jotting down notes.

 

Thank you.

 

Jeff

"Barthonis"

[Bill93]

Some of those should be findable without a metal detector, since they are adjusted locations and some have decent ties that might still be identifiable 35 years later.

 

For those, I'd go to where the coordinates said, figure I was within whatever tolerance the GPS unit indicated, and pick out the landmarks for measurements. If you can find the things to measure from, that ought to get you within a foot. Since I have a metal detector, I would use it next. But if I didn't have it, I would probe with my dandelion digger to see if I could find the rod a few inches down.

 

The one 13 feet from the center of the road may be a problem. Depending on the road that may put it in the shoulder or in the traveled portion. If it is under pavement, you'll just have to note the fact and forget finding it. It originally was probably set at the edge of the gravel or outside the pavement. If they reworked the road in those 35 years then it is probably wiped out. If still gravel, you may still be able to find it but it wouldn't be nice to dig too much of a hole in the road. Again the metal detector would help.

 

Some of those marks may not have careful enough tie measurements, or enough preserved landmarks, to get you that close, so you could need to search several feet around the nominal position. Then the metal detector would really help.

 

Since re-rod is often used to mark land corners, be very slow to claim what you found is the right one and confirm it by the most accurate GPS and tape measurements you can make. If you can identify the land corners by fence lines and roads that will reduce mix-ups.

 

Add to your list of things to carry: a nicely printed copy of the data sheet. It helps convince neighbors and deputy sheriffs that you have some peaceful purpose (however weird) for being there.

 

And be very careful about digging alongside road right of way and yards. The trowel or dandelion digger, gently used, is slower but much less likely to cut a cable than a shovel (even small) under foot pressure.