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Details for Benchmark: HS3878

N 37° 40.200 W 121° 44.950 (NAD 83)

Altitude: 555

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

Location:
In ALAMEDA county, CA View Original Datasheet
Designation:
TES MARI A CO
Marker Type:
survey disk
Setting:
set into the top of a round concrete monument
Stability:
May hold, but of type commonly subject to surface motion.

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Took us a few minutes of study on scene and on the USGS Topo (thanks Delorme PN-40) to realize that Concanon (was Wente, and Wente used to be Marina) used to meet Livermore (was Tesla) coming direct from the south (not at right angles, like now). Still, even seeing that, mark was still not found where it should have been. Might be there, but doubtful. The mark name makes sense now, as it used to be at the corner of Tesla and Marina, before three different street name changes!

Can't call this found (or can I?) because apparently Alameda County replaced it when the City of Livermore built the softball fields. The new one is close, if not exactly where the old one was. If you hunt for this, remember that Wente street used to meet Tesla at an angle. New marker is "Alameda County, LIV-WEN, 1988, Surveyor".

I searched for this one, but most the the landmarks used as references aren't there any more. I suspect that the BM was destroyed either during the widening of S. Livermore (they call it Tesla Rd. here, but it's South Livermore), or when Wente St. was transformed into an extension of Concannon Blvd. Either way, it's probably gone for good.

Documented History (by the NGS)

01/01/1958 by CA-001 (MONUMENTED)
01/01/1961 by NGS (GOOD)
DESCRIBED BY NATIONAL GEODETIC SURVEY 1961 1.2 MI SE FROM LIVERMORE. 1.25 MILES SOUTHEAST ALONG TESLA ROAD FROM THE POST OFFICE AT LIVERMORE, AT THE T JUNCTION OF WENTE STREET, 30 FEET SOUTHWEST OF THE CENTER LINE OF THE ROAD, 95 FEET NORTHWEST OF THE CENTER LINE OF THE STREET, 61 FEET WEST-SOUTHWEST AND ACROSS THE ROAD FROM POWER POLE 23, 1.0 FOOT NORTHEAST OF A FENCE, 2.0 FEET SOUTH-SOUTHEAST OF A 2-BY 6-INCH WITNESS POST, ABOUT LEVEL WITH THE ROAD, AND SET IN THE TOP OF A CONCRETE POST PROJECTING 0.1 FOOT ABOVE THE GROUND.

Control Text

  • The horizontal coordinates were scaled from a topographic map and have an estimated accuracy of +/- 6 seconds.
  • The NAVD 88 height was computed by applying the VERTCON shift value to the NGVD 29 height (displayed under SUPERSEDED SURVEY CONTROL.) The vertical order pertains to the superseded datum.
  • The geoid height was determined by GEOID99.

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