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Details for Benchmark: DH0670

N 33° 27.417 W 086° 57.150 (NAD 83)

Altitude: 498.39

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

Location:
In JEFFERSON county, AL View Original Datasheet
Designation:
12 TCIRR
Marker Type:
survey disk
Setting:
light structures
Stability:
Mark of questionable or unknown stability.

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N 33° 27.417 W 086° 57.171

Woohoo! I found another 100 year-old benchmark disk. Here's what has been submitted to the NGS:

THE MARK IS LOCATED APPROXIMATELY 500 FEET SOUTHWEST FROM THE CROSSING OF THE BIRMINGHAM SOUTHERN RAILWAY AT ALLISON BONNETT MEMORIAL PARKWAY NEAR THE JAYBIRD ROAD EXIT OF I-20/59. THE MARK IS AT A REINFORCED-CONCRETE DOUBLE BOX CULVERT, AND IN THE CENTER OF THE TOP OF THE NORTHWEST HEAD WALL. A TENNESSEE COAL, IRON AND RAILROAD CO. STANDARD DISK, STAMPED 498.00 12 1903.

THE MARK WAS RECOVERED IN GOOD CONDITION. THE COORDINATES OF N 33 27.417 W O86 57.171 WERE RECORDED USING A CONSUMER GRADE GPS UNIT WITH A 5 MINUTE OCCUPATION OF THE MARK WHILE RECEIVING WAAS SIGNALS

[last edit: 11/30/2003 12:04:06 AM PST]

[last edit: 11/30/2003 6:13:52 PM PST]

[Photos:]
photoTCIRR Picture 2
photoTCIRR Picture 1

Documented History (by the NGS)

01/01/1903 by (MONUMENTED)
DESCRIBED 1903 5.0 MI SW FROM ENSLEY. 5.0 MILES SOUTHWEST ALONG THE SOUTHERN RAILWAY FROM THE NINETEENTH STREET FREIGHT STATION AT ENSLEY, JEFFERSON COUNTY, 0.1 MILE SOUTHWEST OF MILEPOST 14, 600 FEET SOUTHWEST OF THE CROSSING OF POSSUM VALLEY ROAD, AT A REINFORCED-CONCRETE DOUBLE BOX CULVERT, AND IN THE CENTER OF THE TOP OF THE NORTHWEST HEAD WALL. A TENNESSEE COAL, IRON AND RAILROAD CO. STANDARD DISK, STAMPED 498.00 12 1903.
01/01/1942 by NGS (GOOD)
RECOVERY NOTE BY NATIONAL GEODETIC SURVEY 1942 RECOVERED IN GOOD CONDITION.
01/01/1980 by NGS (GOOD)
RECOVERY NOTE BY NATIONAL GEODETIC SURVEY 1980 RECOVERED IN GOOD CONDITION.

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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