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Details for Benchmark: HT0309

N 37° 30.583 W 122° 06.700 (NAD 83)

Altitude: 22.3

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

Location:
In ALAMEDA county, CA View Original Datasheet
Designation:
V 553
Marker Type:
bench mark disk
Setting:
massive structures
Stability:
Probably hold position/elevation well.

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Found where described

[Photos:]
photoMark
photoEye level
photoFor reference

Found this one many years ago but apparently never logged. Was out here on a day off so decided to come back and check on the BM.

[Photos:]
photoCloseup
photoCloseup with GPS.
photoChest high shot
photoV533-Area-Shot

Found this benchmark near a waypoint for one of the local multi caches.

N 37° 30.603 W 122° 06.711

Found in good condition. Description adequate.

[Photos:]
photoHT0309 V 553

Found while checking on a nearby cache.

[Photos:]
photoV553
photoGeneral location

knew there must be one on this bridge-thingy...found as we had solved a venona nearby...

Airsax pointed this one out as we were walking back from a Venona Puzzle hide!

[Photos:]
photoWould ya look at that?

Found after the venona hint retrieval.

N 37° 30.603 W 122° 06.708

I actually remembered to look for this after the local Venona activity. Found V553/1956 as described in good conditions. Just ask anyone.

Found this one and waymarked it as WM8XRH.

I spotted this benchmark while walking out on the pier (and former bridge) with my daughter on this Veteran's Day holiday. Nice bonus find! Disk seems in good shape and solid.

[Photos:]
photoHT0309

My GPSr: N 37 30.602, W 122 06.710
Easy to spot on the old bridge/pier. Nice that this has been turned into a fishing pier, even though you really need to walk clear to the end to reach some decent water depth. Will post a few pics. -Batch218-

[Photos:]
photoSurvey mark
Survey mark
photoMark with GPSr
Mark with GPSr
photoIn situ
In situ

One of several found while out at the old Dumbarton Bridge (now fishing pier) today.

[Photos:]
photoV 553 1956
photoLocation
Looking South
N 37° 30.601 W 122° 06.710

I noticed this monument yesterday while doing stage 3 of GC1HQ1W but only had my camera phone for a picture; I went back today with a real camera.

[Photos:]
photoV553

Documented History (by the NGS)

01/01/1956 by CGS (MONUMENTED)
DESCRIBED BY COAST AND GEODETIC SURVEY 1956 AT DUMBARTON BRIDGE. AT DUMBARTON BRIDGE, IN TOP OF THE CONCRETE CURB OVER BENT 117, 177.4 FEET SOUTHWEST OF THE NORTHEAST END OF THE BRIDGE, 177.0 FEET SOUTHWEST OF TIDAL 9, 11 1/2 FEET SOUTHEAST OF THE CENTER LINE OF THE BRIDGE, AND ABOUT 0.8 FOOT HIGHER THAN THE BRIDGE FLOOR.
01/01/1966 by NGS (GOOD)
RECOVERY NOTE BY NATIONAL GEODETIC SURVEY 1966 RECOVERED IN GOOD CONDITION.

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.
  • This Tidal Bench Mark is designated as VM 8151 by the Center for Operational Oceanographic Products and Services.
  • This Tidal Bench Mark is designated as VM 11712 by the Center for Operational Oceanographic Products and Services.
  • The geoid height was determined by GEOID99.

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