Details for Benchmark: AB1313
N 26° 08.950 W 097° 55.800 (NAD 83)
Coordinates may not be exact. Altitude is ADJUSTED and location is SCALED. (more info)
- In HIDALGO county, TX View Original Datasheet
- 120 IBWC
- Marker Type:
- survey disk
- light structures
- May hold, but of type commonly subject to surface motion.
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Documented History (by the NGS)
|Unknown by IBWC (MONUMENTED)
|01/01/1981 by NGS (GOOD)
|DESCRIBED BY NATIONAL GEODETIC SURVEY 1981
1.7 KM (1.1 MI) WEST FROM MERCEDES. 1.7 KM (1.1 MI) WEST ALONG U.S. HIGHWAY 83 BUSINESS FROM THE JUNCTION OF FARM ROAD 491 NORTH IN MERCEDES, AT THE WEST END OF A LARGE BRIDGE OVER THE NORTH FLOODWAY, AT A GATE BARRING ACCESS TO THE WEST LEVEE, SET IN THE TOP OF A CONCRETE WATER CONTROL CISTERN, 41.1 METERS (135 FT) SOUTH OF THE APPROXIMATE CENTERLINE OF THE NEW EASTBOUND LANES OF THE HIGHWAY, 3.4 METERS (11.0 FT) EAST OF THE CENTER OF THE LEVEE ROAD, 11.2 METERS (37.0 FT) NORTH OF THE EAST END OF THE GATE, 53.6 METERS (176.0 FT) SOUTH OF BENCH MARK W 1421 1981. THE MARK IS 0.45 M BELOW LEVEE ROAD.
- 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 June 1991.
- 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.