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Details for Benchmark: HT0031

N 37° 45.927 W 122° 14.514 (NAD 83)

Altitude: 30.87

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

Location:
In ALAMEDA county, CA View Original Datasheet
Designation:
PARK CLARA
Marker Type:
traverse station disk
Setting:
set into the top of a round concrete monument
Stability:
May hold, but of type commonly subject to surface motion.

Reference Points

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Found during the Alameda Art & Wine Festival.

Great coin shop across the street.

[Photos:]
photo0502071136 Park SC.jpg

Documented History (by the NGS)

01/01/1947 by CGS (MONUMENTED)
DESCRIBED BY COAST AND GEODETIC SURVEY 1947 (SPH) STATION IS LOCATED IN THE CENTRAL-EASTERN PART OF THE CITY OF ALAMEDA, IN THE SIDEWALK, 8 FEET NORTH OF THE NORTH CURB OF SANTA CLARA AVE. AND 4 FEET WEST OF THE WEST CURB OF PARK STREET. MARKED BY A STANDARD TRAVERSE STATION DISK, STAMPED PARK CLARA 1947, SET IN TOP OF A CONCRETE POST 6 INCHES SQUARE AT THE TOP, 6 BY 10 INCHES AT THE BOTTOM, AND 30 INCHES LONG. THE MARK IS ABOUT 10 INCHES BELOW THE SURFACE OF THE SIDEWALK, AND IS ACCESSIBLE THROUGH A SMALL MANHOLE COVERED WITH A CITY OF OAKLAND IRON LID INSCRIBED WITH CITY MONUMENT.
01/01/1951 by NGS (GOOD)
RECOVERY NOTE BY NATIONAL GEODETIC SURVEY 1951 AT ALAMEDA. AT ALAMEDA, AT THE NORTHWEST CORNER OF THE INTERSECTION OF SANTA CLARA AND PARK STREET, 5.8 FEET NORTH OF THE PROLONGATION OF THE NORTH CURB OF THE AVENUE, 3.8 FEET WEST OF THE PROLONGATION OF THE WEST CURB OF THE STREET, 0.8 FOOT BELOW THE SURFACE OF THE SIDEWALK, AND ENCASED IN AN 8-INCH IRON PIPE WITH A CAST IRON COVER FLUSH WITH THE SIDEWALK.
01/01/1963 by NGS (GOOD)
RECOVERY NOTE BY NATIONAL GEODETIC SURVEY 1963 RECOVERED IN GOOD CONDITION.
01/01/1986 by USPSQD (GOOD)
RECOVERY NOTE BY US POWER SQUADRON 1986 (RJS) RECOVERED IN GOOD CONDITION.
10/11/1988 by NGS (GOOD)
RECOVERY NOTE BY NATIONAL GEODETIC SURVEY 1988 RECOVERED IN GOOD CONDITION.

Control Text

  • The horizontal coordinates were established by classical geodetic methods and adjusted by the National Geodetic Survey in March 1994. The horizontal coordinates are valid at the epoch date displayed above. The epoch date for horizontal control is a decimal equivalence of Year/Month/Day.
  • The orthometric height was determined by differential leveling and adjusted by the National Geodetic Survey in June 1991.
  • This Tidal Bench Mark is designated as VM 7559 by the Center for Operational Oceanographic Products and Services.
  • The Laplace correction was computed from DEFLEC99 derived deflections.
  • 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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