Details for Benchmark: HS1427
N 37° 03.700 W 120° 32.567 (NAD 83)
Coordinates may not be exact. Altitude is ADJUSTED and location is SCALED. (more info)
- In MERCED county, CA View Original Datasheet
- H 1235 RESET
- Marker Type:
- vertical control disk
- abutments and piers of large bridges
- Probably hold position/elevation well.
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||Wintertime posted a note for HS1427
Interesting article about ground subsidence in the San Joaquin Valley that includes a USGS photo showing how much H 1235 RESET dropped between 1988 and 2013:
Documented History (by the NGS)
|01/01/1975 by CADH (MONUMENTED)
|DESCRIBED BY CA DIV OF HIGHWAYS 1975
16 MI SW FROM CHOWCHILLA. 2.75 MILES SOUTHWEST ALONG STATE HIGHWAY 233 FROM WILSON GRAMMAR SCHOOL AT CHOWCHILLA, THENCE 14.15 MILES WEST ALONG STATE HIGHWAY 152, ON THE NORTHEAST WINGWALL OF THE EASTBOUND LANE BRIDGE NO. 39-24R OVER FRESNO RIVER AT 8.35 FEET WEST OF THE END OF THE WINGWALL, AND 0.60 FOOT SOUTH OF THE FACE OF THE SECOND RAIL POST ON THE BRIDGE.
|11/15/1988 by NGS (GOOD)
|RECOVERY NOTE BY NATIONAL GEODETIC SURVEY 1988
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 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.