Details for Benchmark: HS5455
N 37° 41.717 W 121° 43.883 (NAD 83)
Coordinates may not be exact. Altitude is VERTCON and location is SCALED. (more info)
- In ALAMEDA county, CA View Original Datasheet
- N 832 RESET
- Marker Type:
- vertical control disk
- retaining walls, concrete ledge, etc.
- May hold, but of type commonly subject to surface motion.
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Documented History (by the NGS)
|01/01/1989 by LOCENG (MONUMENTED)
|DESCRIBED BY LOCAL ENGINEER (INDIVIDUAL OR FIRM) 1989
2.3 MILES (3.7 KM) NORTHEAST ALONG THE SOUTHERN PACIFIC RAILROAD FROM THE STATION IN LIVERMORE, SOUTHWEST CORNER OF BOX CULVERT ON THE ARROYO SECO CHANNEL, 19 FEET (5.8 M) SOUTHEAST OF THE CENTERLINE OF THE UNION PACIFIC RAILROAD TRACKS, 0.1 MILE (0.2 KM) NORTHWEST OF PATTERSON PASS ROAD, 20 FEET (6.1 M) NORTHWEST OF INTERSECTION OF ARROYO SECO CHANNEL AND ARROYO LOS POSITAS CHANNEL, IN THE TOP OF CONCRETE WALL.
- 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- The NAVD 88 height was computed by applying the VERTCON shift value to the NGVD 29 height (displayed under SUPERSEDED SURVEY CONTROL.) The vertical order pertains to the superseded datum.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.