Skip to Content

Details for Benchmark: AI7613

N 38° 49.883 W 077° 02.500 (NAD 83)

Altitude: 4.5

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

Location:
In C OF ALEXANDRIA county, VA View Original Datasheet
Designation:
A 513
Marker Type:
vertical control disk
Setting:
mat foundation, concrete slab, etc.
Stability:
May hold, but of type commonly subject to surface motion.

Must Read!

Benchmarks may be on private property or in dangerous locations. Obey local laws. By using the services on Geocaching.com you agree to this disclaimer.

Easy find right next to a parking lot.

[Photos:]
photoA513 Close
photoA513 Area

Found in good condition

[Photos:]
photoclose up of benchmark
photoview of location

Found as described, in good condition. Did not appear to be affected by construction noted in earlier find.

[Photos:]
photoAI7613 mark: A 513 Alexandria VA
Mark and GPSr
photoAI7613 area N: A 513 Alexandria VA
View to the N, mark is at lower left center, indicated by notebook. Calm waters of marina in background, and a pleasant but cool early spring day.

Found as described, approximately 6 feet north of a DC fishing regulations sign on a wooden post.

Note: improvements to the marina are currently underway which may result in changes to this station, which sits at a retaining wall on the south end of the marina.

[Photos:]
photoCloseup of station A 513, Alexandria, VA (AI7613)
photoArea view, station A 513, Alexandria, VA (AI7613)
View is to the north, showing construction work at Marina. Yellow arrow indicates location of station disk.
N 38° 49.875 W 077° 02.533

The benchmark seemed to be about 160 feet WSW of the listed location. However, the description make it quite obvious where the benchmark is.

[Photos:]
photoNorth from AI7613
photoBenchmark A 513 in Alexandria, Virginia
The disk.

Documented History (by the NGS)

01/01/2000 by NGS (MONUMENTED)
DESCRIBED BY NATIONAL GEODETIC SURVEY 2000 (DBC) 0.6 MILE (1.0 KM) NORTH ALONG THE G W PARKWAY FROM THE JUNCTION OF SLATERS LANE IN ALEXANDRIA TO THE JUNCTION OF MARINA DRIVE. THENCE 0.05 MILE (0.08 KM) EAST ALONG MARINA DRIVE LEADING INTO THE WASHINGTON SAILING MARINA TO A Y JUNCTION, THENCE 0.1 MILE (0.2 KM) NORTHEAST ALONG ROAD TO JUNCTION OF PARKING AREA, THENCE 0.05 MILE (0.08 KM) WESTERLY TO MARK ON RIGHT. 7.0 FEET (2.1 M) SOUTH OF THE NORTH EDGE OF RETAINNG WALL, 6 INCHES SOUTH OF A CUT OFF STEEL FRAME (14 INCHES HIGH) , 36.0 FEET (11.0 M) NORTH OF APPROXIMATE CENTERLINE OF PARKING AREA ROAD, 45.9 FEET (14.0 M) EAST OF WEST END OF RETAIN WALL, 42.0 FEET (12.8 M) WEST OF EAST END OF RETAIN WALL.

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 November 2000.
  • 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.

Advertising with Us

Return to the Top of the Page