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Details for Benchmark: RD0426

N 45° 38.983 W 122° 45.800 (NAD 83)

Altitude: 41.09

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

Location:
In MULTNOMAH county, OR View Original Datasheet
Designation:
KELLEY RM 1
Marker Type:
reference mark disk
Setting:
setting not listed - see description
Stability:
Mark of questionable or unknown stability.

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Found while geocaching

[Photos:]
photoReference mark

Found with Dr.Safeway today. He dived into the brush and spotted the witness stake and the ribbon flag. I brushed the sand away and uncovered the benchmark. It has some gouge marks across the top, but overall, is in pretty good condition.
We were unable to locate the actual benchmark or the other reference marks.

[Photos:]
photoRD0426 - KELLEY RM 1 - witness post/location
photoRD0426 - KELLEY RM 1 - Disk

Recovered RM1 in good condition at Kelley Point Park.

We found RM1 at approximately 54 feet* east-southeast of triangulation station Kelley (rather than just the “east” that it says in the description).
* The 54 feet is approximate. While we were measuring, we were attacked by a hoard of crazed mosquitoes. During the arm flapping and slapping that ensured we neglected to make a final stretch and alignment of the tape.

RM1 is a few feet lower than the station mark.

We found the mark at 1 foot west-southwest of a metal post with no sign.

The station mark KELLEY is in a mowed park lawn. RM1 is about 5 meters back into the brush surrounding the lawn.

[Photos:]
photoRD0426 - RM1 Disk – Portland, Oregon
photoRD0426 – Top down view.
photoRD0426 - Looking approximately east

Documented History (by the NGS)

01/01/1938 by CGS (MONUMENTED)
01/01/1972 by NGS (GOOD)
DESCRIBED BY NATIONAL GEODETIC SURVEY 1972 4 MI W FROM NORTH PORTLAND. REACHED FROM THE NORTH PORTLAND POST OFFICE, GO WEST ON MARINE DRIVE FOR 0.7 MILE TO SUTTLE ROAD ON THE RIGHT, TURN RIGHT, AND GO WEST ON SUTTLE ROAD, TOWARD KELLEY PARK, FOR 4.2 MILES TO THE END OF THE ROAD, AT THE CONFLUENCE OF THE COLUMBIA, AND WILLAMETTE RIVERS, AND THE MARK, 350 FEET SOUTHEAST OF THE CONFLUENCE OF THE RIVERS, 54 FEET EAST OF TRIANGULATION STATION KELLEY 1938, AND 1 FOOT NORTH OF A METAL WITNESS POST.
01/01/1990 by USPSQD (MARK NOT FOUND)
RECOVERY NOTE BY US POWER SQUADRON 1990 (FV) MARK NOT FOUND.
06/28/1994 by USPSQD (MARK NOT FOUND)
RECOVERY NOTE BY US POWER SQUADRON 1994 MARK NOT FOUND.

Control Text

  • The horizontal coordinates were scaled from a topographic map and have an estimated accuracy of +/- 6 seconds.
  • The orthometric height was determined by differential leveling and adjusted by the National Geodetic Survey in 1992. No vertical observational check was made to the station. * This is a POSTED BENCH MARK height. Code NC indicates the bench mark was located on a no-check spur therefore a value was not computed.
  • 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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