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Details for Benchmark: CG0028

N 31° 58.650 W 110° 13.567 (NAD 83)

Altitude: 3777.37

Coordinates may not be exact. Altitude is ADJUSTED and location is SCALED. (more info)

Location:
In COCHISE county, AZ View Original Datasheet
Designation:
216+24
Marker Type:
survey disk
Setting:
massive structures
Stability:
Probably hold position/elevation well.

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Found it.

N 31° 58.667 W 110° 13.558

Found in good shape, as described.

[Photos:]
photoCG0028

Found the one on the north side of the bridge, but totally missed this one and had to go back to get it. Good condition, nice clear date on this disc.

[Photos:]
photoCG0028 marker
photolocation of disc, mid-bridge.
Looking westwards along the south headwall of the bridge. CG0029 marker is mid-way on the north headwall of bridge.
photolooking southerly at the next bridge downstream
Three bridges over a short stretch of wash. First the current I-10 bridge,then the old 1940 Hwy 80 bridge, then the Railroad bridge.

Documented History (by the NGS)

Unknown by AZHD (MONUMENTED)
01/01/1952 by NGS (GOOD)
DESCRIBED BY NATIONAL GEODETIC SURVEY 1952 4.5 MI NE FROM BENSON. 4.45 MILES NORTHEAST ALONG THE SOUTHERN PACIFIC COMPANY RAILROAD FROM THE STATION AT BENSON TO RAILROAD BRIDGE 1037.20, THENCE 0.05 MILE NORTHWEST ALONG THE BANK OF A WASH TO THE LARGE HIGHWAY BRIDGE, IN TOP OF THE CENTER OF THE SOUTHEAST CONCRETE HEADWALL OF STATE HIGHWAY 86 BRIDGE, 361.0 FEET NORTHWEST OF THE NORTHWEST EDGE OF BRIDGE 1037.20, 17 1/2 FEET SOUTHEAST OF THE CENTER LINE OF THE HIGHWAY, ABOUT 0.7 FOOT HIGHER THAN THE HIGHWAY.
01/01/1979 by NGS (GOOD)
RECOVERY NOTE BY NATIONAL GEODETIC SURVEY 1979 8.4 KILOMETERS (5.25 MILES) EAST ALONG INTERSTATE HIGHWAY 10 FROM THE OCOTILLO STREET UNDERPASS AT BENSON, AT A FRONTAGE ROAD BRIDGE OVER A DRY WASH, IN THE TOP CENTER OF THE SOUTHEAST CURB, 4.8 METERS (15.5 FEET) SOUTHEAST OF THE CENTERLINE OF THE FRONTAGE ROAD AND 21.9 METERS (72 FEET) SOUTHWEST OF THE NORTHEAST END OF THE CURB. THE MARK IS 0.1 M ABOVE FRONTAGE ROAD.

Control Text

  • The horizontal coordinates were scaled from a topographic map and have an estimated accuracy of +/- 6 seconds.
  • The orthometric height was determined by differential leveling and adjusted by the National Geodetic Survey in June 1991.
  • The geoid height was determined by GEOID99.
  • The dynamic height is computed by dividing the NAVD 88 geopotential number by the normal gravity value computed on the Geodetic Reference System of 1980 (GRS 80) ellipsoid at 45 degrees latitude (G = 980.6199 gals.).
  • The modeled gravity was interpolated from observed gravity values.

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