Details for Benchmark: RD0427
N 45° 38.983 W 122° 45.800 (NAD 83)
Coordinates may not be exact. Altitude is POSTED and location is SCALED. (more info)
- In MULTNOMAH county, OR View Original Datasheet
- KELLEY RM 2
- Marker Type:
- reference mark disk
- set into the top of a metal pipe driven into the ground
- Mark of questionable or unknown stability.
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||TillaMurphs found RD0427
Recovered RM2 in good condition.
Regarding the 1972 description:
Our best estimate for distance to “confluence of the rivers” is about 400 feet. That was paced off while contending with brush/trees so it is a rough estimate. It would also depend on the “tide” line of the rivers edge when starting the measurement.
We did find RM2 at 41 feet approximately south of triangulation station disk KELLEY.
There is no witness post of any kind.
The mark was about 1 inch below the surface.
We found RM2 at 25.5 feet south from an in-ground rod topped with a red plastic survey cap marker. The red cap says “MULT. CO. CONTROL” and is flush with the ground.
RM2 and the station mark are in a mowed park lawn.
(Our Gamin nuvi 760 GPSr gave RM2’s location as: N 45° 38.994 W 122° 45.813 (with “14 Foot Accuracy”).)
[Photos:]RD0426 - RM2 Disk – Portland, Oregon
RD0426 - Eye level view of RD0426.
The grayish mounds are not rocks – they are sand pushed up by moles.
RD0426 - Looking south-southeast.
The orange cap in the foreground is sitting on the station mark. The yellow device further away on the right side of the photo is sitting on top of the RM2 disk.
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 BENCH MARK, 350 FEET SOUTHEAST OF THE CONFLUENCE OF THE RIVERS, 41 FEET SOUTH OF TRIANGULATION STATION KELLEY 1938, AND 1 FOOT WEST OF A METAL WITNESS POST, SET IN CONCRETE IN A 4-INCH PIPE THAT PROJECTS 3 INCHES.
|01/01/1990 by USPSQD (GOOD)
|RECOVERY NOTE BY US POWER SQUADRON 1990 (FV)
RECOVERED IN GOOD CONDITION.
|06/28/1994 by USPSQD (GOOD)
|RECOVERY NOTE BY US POWER SQUADRON 1994
RECOVERED IN GOOD CONDITION.
- 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.