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Details for Benchmark: DY0785

N 33° 48.624 W 118° 04.515 (NAD 83)

Altitude: 39.93

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

Location:
In ORANGE county, CA View Original Datasheet
Designation:
CC 6
Marker Type:
traverse station disk
Setting:
abutments and piers of large bridges
Stability:
Probably hold position/elevation well.

Must Read!

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Interesting location. Fun to find.

Out for a bike ride and noticed this mark along the way. Funny thing is that it was actually not loaded into my GPSr at the time. I photo'd anyway just in case. Most times, these "extra" marks are not NGS listed marks, but this one is not only one that they are interested in, but also one of the ultra accurate adjusted both horizontally and vertically.

[Photos:]
photoDY0785
Close-up of the mark.
photoDY0785 Location
Location of the mark.
photoDY0785 Area
The area around the mark.

Out on a power benchmarking day with Sparqui & LBGUZ5...one of 13 located today. Pictures to follow.

Found at 1:15PM today.

[Photos:]
photoEasy enough to spot

Recovered as described.

[Photos:]
photoCloseup of DY0765 Disc
near Los Alamitos, CA
photoImmediate DY0765 disc area w/ PID!
Very seldom (around here) do you see the correct PID labeled near the mark. Often it is a local city or county number(in paint), not the NGS PID. Kinda rare. This one is nicely inscribed in the cement, probably done when still wet.
photoFurther area of DY0765 in the LA area
This location is a bit sporty, as it is in the center median of the bridge, on a quite busy road! Gotta be careful!
N 33° 48.626 W 118° 04.514

Recovered in good condition. This benchmark was placed in 1957.

[Photos:]
photoBenchmark
photoLooking west

Documented History (by the NGS)

01/01/1957 by DOD (MONUMENTED)
01/01/1968 by CA-037 (GOOD)
DESCRIBED BY LOS ANGELES COUNTY CALIFORNIA 1968 AT LOS ALAMITOS. 900 FEET WEST ALONG CERRITOS AVENUE FROM ITS INTERSECTION WITH LOS ALAMITOS BOULEVARD TO BRIDGE B 1110 OVER COYOTE CREEK, 15 FEET NORTH OF THE CENTER OF THE EAST BOUND TRAFFIC LANES OF CERRITOS AVENUE, 2 FEET EAST OF THE EAST END OF THE STEEL GUARD RAIL ON THE NORTH SIDE OF THE BRIDGE, 1.0 FOOT SOUTH OF THE NORTH EDGE OF THE BRIDGE, IN THE TOP OF THE CONCRETE BRIDGE ABUTMENT AND ABOUT 1.0 FOOT ABOVE THE LEVEL OF THE ROAD.
01/01/1974 by CA-059 (GOOD)
RECOVERY NOTE BY ORANGE COUNTY CALIFORNIA 1974 RECOVERED IN GOOD CONDITION.
01/01/1978 by NGS (GOOD)
RECOVERY NOTE BY NATIONAL GEODETIC SURVEY 1978 RECOVERED IN GOOD CONDITION.
04/17/1989 by NGS (GOOD)
RECOVERY NOTE BY NATIONAL GEODETIC SURVEY 1989 RECOVERED IN GOOD CONDITION. A NEW DESCRIPTION FOLLOWS. 0.3 KM (0.20 MI) WESTERLY ALONG CERRITOS AVENUE FROM THE JUNCTION OF LOS ALAMITOS BOULEVARD IN LONG BEACH, IN TOP OF AND 12.5 M (41.0 FT) NORTHEAST OF THE SOUTHWEST END OF THE EAST CONCRETE ABUTMENT OF THE BOULEVARD BRIDGE SPANNING COYOTE CREEK, 5.4 M (17.7 FT) NORTH OF THE CENTERLINE OF THE EASTBOUND LANES OF THE BOULEVARD, AND 0.3 M (1.0 FT) ABOVE THE LEVEL OF THE BOULEVARD.
08/16/1994 by CA-059 (GOOD)
RECOVERY NOTE BY ORANGE COUNTY CALIFORNIA 1994 (JK) RECOVERY NOTE BY ORANGE COUNTY CALIFORNIA 1994. RECOVERED AS DESCRIBED BY NATIONAL GEODETIC SURVEY 1989.

Control Text

  • The horizontal coordinates were established by GPS observations and adjusted by the National Geodetic Survey in November 1995. This is a SPECIAL STATUS position. See SPECIAL STATUS under the DATUM ITEM on the data sheet items page. 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. WARNING-Repeat measurements at this control monument indicate possible vertical movement.
  • The X, Y, and Z were computed from the position and the ellipsoidal ht.
  • The Laplace correction was computed from DEFLEC99 derived deflections.
  • The ellipsoidal height was determined by GPS observations and is referenced to NAD 83.
  • 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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