Below Ground Level

[+Spoo]

This is the first Station mark, that I have come across, that was purposely placed below ground level. OC2676

 

OC2676'THE STATION MARK IS A STANDARD DISK STAMPED--DEERING 1975--,

OC2676'THE SURFACE DISK IS CEMENTED IN A DRILL HOLE IN SUBSURFACE

OC2676'BEDROCK WHICH IS 1.8 FEET BELOW THE GROUND SURFACE.

OC2676'IT IS 19-FEET WEST-SOUTHWEST OF A ROCK WALL, 21 FEET

OC2676'NORTH-NORTHWEST OF A STUMP IN A ROCK WALL AND 23 FEET

OC2676'EAST OF THE SOUTHEAST FENCE CORNER WHICH SURROUNDS

OC2676'THE MICROWAVE TOWER.

 

Maine mountains and hills are practically all granite. Our forests cover the ground at a rate of about one inch every ten years.

 

Does anyone have any ideas why someone would mount a disk below ground level?

 

With the help of two very enthusiastic abutting property owners, we located this mark originally because a large slit-style depression was in the correct area and there was a very large marker post of some sort broken off and in the hole. It was not a post typical of a Witness Post, it was much larger, and the description does not mention a Witness Post.

 

We dug and found the marker to be about 15 inches deep in the depression. Unfortunately, my photos of the mark in the hole did not come out worth crap.

 

EDIT NOTE: Anyone else ever come across these subsurface marks?

Edited September 23, 2005 by Spoo

[mloser]

I have read descriptions of a number of marks intentionally set below ground level, but have not successfully recovered any. I think the main reason would be to prevent accidental or deliberate destruction. The ones I recall were set in farm fields or yards, so they were set below the level that they would be disturbed.

 

The only one I really tried to look for remains unfound because I could not locate the reference marks to help measure from and the description was just a bit TOO vague to locate the station without the RMs. It was also 18 inches deep so randomly probing was somewhat fruitless (yeah, I tried it!).

[Difficult Run]

Could they be set at that depth to be below the frostline??

[+Spoo]

Difficult Run:

 

My flat answer is I do not think so.

 

As I stated earlier, most of Maine is one big piece of granite; not subject to much movement.

 

Also, the frost line in these parts is considered to be in the range of 4-6 foot deep.

[2oldfarts (the rockhounders)]

We found N 368 and the datasheet says "NOTE--REBURY BM AFTER USE TO INSURE ITS SECURITY."

 

The disk is set in what used to be a rest area along Hwy 89 in southern Utah. There is a nearby mark (with-in 100 feet of N 368) that has only the stem left. This maybe the reason for burying the mark.

 

John

[Bill93]

As matt mentions, out here in the midwest the majority of triangulation stations were placed in farm fields a few yard from the fence line, or occasionally in yards. This kept them out of the way of road rebuilding, as the small mud roads were widened, gravelled, and eventually paved. In order to not have them disturbed by farming, they were buried by typically 18 inches. I've seen that depth change up or down in later recovery reports.

[holograph]

There's one in my neighborhood that was set below ground because there was insufficient soil depth to set a post and surface mark. See the description for Woodport (LY2619).

[+ddnutzy]

I have found a few benchmarks listed as underground. The only three that I remember are MY3817 which is 12 inches, MY3795 at 18 inches under and LX4706 at 12 inches. There is another one at 6 inches that I'm going for in the near future.

 

Dave

[Z15]

There is a 50 mile long strecth of NOS/USLS marks in upper Michigan that run from Port Inland near Gulliver on Lake Michigan to Marquette on Lake Superior. All the rod driven marks in this run are set about 1 ft more or less below ground level. It was a way to protect them, if they are on the surface they can be hit or knocked out of position very easily. Bury them and they will survive a lot longed.

 

Only problem is that its makes it harded to find them when the sruface references are gone. Here is one I found in 2000, if we had not set a NGS orange witness post, the USPSQD would have never found it, the pole was cuf-off and rotting, hiding..

 

1 National Geodetic Survey, Retrieval Date = SEPTEMBER 24, 2005

RK0390 ***********************************************************************

RK0390 DESIGNATION - LSC 7 B 42

RK0390 PID - RK0390

RK0390 STATE/COUNTY- MI/MARQUETTE

RK0390 USGS QUAD - GWINN (1975)

RK0390

RK0390 *CURRENT SURVEY CONTROL

RK0390 ___________________________________________________________________

RK0390* NAD 83(1986)- 46 18 18. (N) 087 22 37. (W) SCALED

RK0390* NAVD 88 - 349.476 (meters) 1146.57 (feet) ADJUSTED

RK0390 ___________________________________________________________________

RK0390 GEOID HEIGHT- -34.42 (meters) GEOID03

RK0390 DYNAMIC HT - 349.487 (meters) 1146.61 (feet) COMP

RK0390 MODELED GRAV- 980,635.7 (mgal) NAVD 88

RK0390

RK0390 VERT ORDER - FIRST CLASS 0

RK0390

RK0390.The horizontal coordinates were scaled from a topographic map and have

RK0390.an estimated accuracy of +/- 6 seconds.

RK0390

RK0390.The orthometric height was determined by differential leveling

RK0390.and adjusted by the National Geodetic Survey in June 1991.

RK0390

RK0390.The geoid height was determined by GEOID03.

RK0390

RK0390.The dynamic height is computed by dividing the NAVD 88

RK0390.geopotential number by the normal gravity value computed on the

RK0390.Geodetic Reference System of 1980 (GRS 80) ellipsoid at 45

RK0390.degrees latitude (g = 980.6199 gals.).

RK0390

RK0390.The modeled gravity was interpolated from observed gravity values.

RK0390

RK0390; North East Units Estimated Accuracy

RK0390;SPC MI N - 169,190. 7,970,960. MT (+/- 180 meters Scaled)

RK0390

RK0390 SUPERSEDED SURVEY CONTROL

RK0390

RK0390.No superseded survey control is available for this station.

RK0390_U.S. NATIONAL GRID SPATIAL ADDRESS: 16TDS709280(NAD 83)

RK0390_MARKER: I = METAL ROD

RK0390_SETTING: 46 = COPPER-CLAD STEEL ROD W/O SLEEVE (10 FT.+)

RK0390_SP_SET: COPPER-CLAD STEEL ROD

RK0390_PROJECTION: RECESSED 25 CENTIMETERS

RK0390_STABILITY: B = PROBABLY HOLD POSITION/ELEVATION WELL

RK0390_SATELLITE: THE SITE LOCATION WAS REPORTED AS SUITABLE FOR

RK0390+SATELLITE: SATELLITE OBSERVATIONS - May 25, 2000

RK0390_ROD/PIPE-DEPTH: 7.62 meters

RK0390

RK0390 HISTORY - Date Condition Report By

RK0390 HISTORY - 1975 MONUMENTED NOS

RK0390 HISTORY - 20000525 GOOD MIDT

RK0390 HISTORY - 20041101 GOOD USPSQD

RK0390

RK0390 STATION DESCRIPTION

RK0390

RK0390'DESCRIBED BY NATIONAL OCEAN SERVICE 1975

RK0390'2.25 MI NW FROM LITTLE LAKE.

RK0390'2.25 MILES NORTHWEST ALONG THE CHICAGO AND NORTHWESTERN RAILROAD

RK0390'FROM THE STATION AT LITTLE LAKE, 2.1 MILE NORTHWEST OF CO. RD.

RK0390'456, AT SWANZY LAKE RD. 97 FT. SOUTHWEST OF CENTERLINE OF TRACK,

RK0390'25.5 FT. NORTHWEST CENTERLINE OF SWANZY LAKE RD., 4.7 FT. WEST OF

RK0390'UTILITY POLE NUMBER 4116, 10 INCHES BELOW GROUND SURFACE.

RK0390

RK0390 STATION RECOVERY (2000)

RK0390

RK0390'RECOVERY NOTE BY MICHIGAN DEPARTMENT OF TRANSPORTATION 2000 (MPR)

RK0390'FROM JUNCTION OF HWY'S M35 AND M553 GO 1 MI -E- ALONG HWY 35, THENCE 2

RK0390'MILE -N- ALONG MARSHALL DR (FORMALLY 553), THENCE 0.8 MI -NE- ALONG

RK0390'(GRAVEL) SWANZY LAKE RD TO RAILROAD AND MARK ON LEFT. 97 FT -S- OF

RK0390'C/L RR, 59.4 GT -W- OF GAS LINE MARKER, 4.6 FT -W- OF CUTOFF POLE, 1

RK0390'FT -W- OF WITNESS POST, 0.8 FT BELOW GROUND ENCASSED IN CONCRETE PIPE.

RK0390'

Edited September 24, 2005 by Z15