Details for Benchmark: HV8452
N 38° 46.755 W 077° 23.699 (NAD 83)
Coordinates may not be exact. Altitude is VERTCON and location is ADJUSTED. (more info)
- In FAIRFAX county, VA View Original Datasheet
- HDY 1
- Marker Type:
- NGS Benchmark
- setting not listed - see description
- Mark of questionable or unknown stability.
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Documented History (by the NGS)
|01/01/1975 by VA-059 (MONUMENTED)
|DESCRIBED BY FAIRFAX COUNTY VIRGINIA 1975 (WTL)
THE STATION IS LOCATED ABOUT 4.45 SOUTHEAST OF CENTREVILLE, 3.6 MILES SOUTHWEST OF BUTTS CORNER AND 0.45 MILES WEST OF CLIFTON OUT ON THE POWER LINE ON TOP OF A HILL OVER LOOKING THE RAILROAD. SEE FAIRFAX COUNTY TAX MAP 75-4.
TO REACH THE STATION FROM INTERSECTION OF MAIN STREET AND THE RAILROAD TRACKS IN CLIFTON, PROCEED NORTHERLY 0.05 MILES TO CLIFTON CREEK DRIVE, LEFT. THENCE LEFT ON CLIFTON CREEK DRIVE FOR 0.45 MILES TO OVERHEAD POWER LINES. CLIFTON CREEK DRIVE VEERS RIGHT HALF WAY THROUGH THE 0.45 MILES, KEEP TO THE LEFT ON A DIRT ROAD THAT PARALLELS THE RAILROAD TRACKS. HDY-1 IS ON TOP OF THE HILL ON THE RIGHT AND SETS IN BETWEEN THE RAILROAD AND TOWE NUMBER 566/66.
THE STATION IS A REINFORCEING ROD WITH PLASTIC CAP STAMPED---FAIRFAX CO DPW SUR--- IN THE GROUND ABOUT 3 INCHES BELOW THE GROUNDS SURFACE LOCATED 13. FEET W FROM CENTER LINE OF DIRT AND ROCK ROAD AND 39. FEET SE FROM POWER LINE TOWER NUMBER 566/66.
REFERENCE MARK NO. 01 IS A FILED X ON TOP OF A BOLT IN THE CONCRETE FOOTER WHICH IS MOST WESTERLY FROM THE DIRT ROAD AND NEAREST THE WOODS LINE. TOWER NUMBER 566/66.
REFERENCE MARK NO. 02 IS A FILED X ON TOP OF A BOLT IN THE CONCRETE FOOTER WHICH IS MOST EASTERLY FROM THE WESTERN WOODS LINE AND IS CLOSEST TO THE DIRT ROAD. TOWER NUMBER 566/66.
- The horizontal coordinates were established by classical geodetic methods and adjusted by the National Geodetic Survey in November 1994.
- The NAVD 88 height was computed by applying the VERTCON shift value to the NGVD 29 height (displayed under SUPERSEDED SURVEY CONTROL.)
- The Laplace correction was computed from DEFLEC99 derived deflections.
- The geoid height was determined by GEOID99.