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Details for Benchmark: DX4800

N 33° 57.318 W 117° 53.484 (NAD 83)

Altitude: 1423

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

Location:
In LOS ANGELES county, CA View Original Datasheet
Designation:
BREA UNDERGROUND
Marker Type:
triangulation station disk
Setting:
surrounded by a mass of concrete
Stability:
May hold, but of type commonly subject to surface motion.

Reference Points

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Area accessed through Aera Energy oil field (changing to Linn Western in April 2007). The 1988 To Reach description is adequate, but Google Earth is also a big help.

Station Mark and RM 4 recovered as described. The other RM(s) were not found, with use of metal detector. Dry standing brush makes it difficult in many areas.

[Photos:]
photoDX4800 well cover near Brea, CA
I guess it's called "Brea Underground for a good reason! It really is underground. Not too hard to access. Cover shown here with my clipboard for scale.
photoDX4800 Well Cover open
photoDX4800 Disc inside the well north of Brea, CA
photoDX4800 RM4 Disc
photoView of DX4800 RM4 and the OC mountains
Mountains are the Santa Ana's, which are the highest in Orange County (CA), at about 6,500 feet.
photoSeveral of the many cows in the area
Lots of them out in this area, including many calves. In the background is one of the radar mounts of the old Nike missile site.

Documented History (by the NGS)

01/01/1974 by NGS (MONUMENTED)
DESCRIBED BY NATIONAL GEODETIC SURVEY 1974 (JLC) THE UNDERGROUND STATION MARK, AZIMUTH MARK AND REFERENCE MARK 2 WERE RECOVERED IN GOOD CONDITION. A REFERENCE MARK 3 WAS ESTABLISHED AT THIS TIME. DUE TO THE ABOVE CHANGES A NEW DESCRIPTION FOLLOWS. THE STATION IS LOCATED 4 MILES NORTHEAST OF LA HABRA, 3 MILES NORTH OF BREA, 1.5 MILES WEST OF STATE HIGHWAY 57, 1.0 MILE NORTH OF LOS ANGELES-ORANGE COUNTY LINE AND 0.5 MILE EAST OF NIKE MISSILE SITE. IT IS IN THE SE 1/4 SEC. 35, R10W, T2S ON PROPERTY OF THE SHELL OIL COMPANY WHO HAS AN OFFICE IN BREA. PHONE 529-2478. TO REACH THE STATION FROM THE U.S. POST OFFICE IN BREA GO NORTH ON NORTH BREA BLVD. FOR 1.0 MILE TO A CROSSROAD. TURN LEFT AND GO WEST ON CENTRAL AVE. FOR 0.5 MILE TO A SIDE ROAD ON THE RIGHT. TURN RIGHT AND GO NORTH ON SITE DRIVE FOR 1.0 MILE TO A GATE. PASS THROUGH GATE AND CONTINUE FOLLOWING MAIN ROAD FOR 0.15 MILE TO A FIVE-WAY FORK, TURN LEFT AND FOLLOW LOWER ROAD (MAIN PAVED ROAD) UPHILL FOR 3.5 MILES TO A LOCKED GATE AHEAD AND A SIDEROAD ON THE RIGHT. TURN RIGHT AND GO EAST ON MAIN ROAD FOR 0.5 MILE TO THE AZIMUTH MARK ON THE RIGHT. CONTINUE ON MAIN PAVED ROAD FOR 0.15 MILE TO A SIDEROAD ON THE RIGHT. TURN RIGHT ON DIRT ROAD AND GO EAST FOR 0.15 MILE TO TOP OF HILL AND THE STATION. THE STATION MARK IS A STANDARD DISK STAMPED ---BREA 1938---. IT IS COVERED WITH A 7-INCH ROUND STOVE PIPE AND A 9-INCH METAL COVER WHICH HAS MONUMENT COUNTY ENGINEER IN RAISED LETTERS ON THE TOP. IT IS 59 EET SOUTHWEST OF A METAL WITNESS POST, 55 FEET NORTHWEST OF WEST EDGE OF HILL AND 2.3 FEET NORTH OF METAL PIPE WITNESS POST (IT IS MINUS 16 INCHES). REFERENCE MARK 2 IS A STANDARD DISK STAMPED ---BREA NO 2 1938---SET IN THE TOP OF A 8-INCH CYLINDRICAL CONCRETE MONUMENT THAT IS FLUSH WITH THE GROUND SURFACE. IT IS 69 FEET SOUTHWEST OF A METAL WITNESS POST AND 1.8 FEET NORTH OF A PIPE WITNESS POST. REFERENCE MARK 3 IS STANDARD DISK STAMPED ---BREA 1938 NO 3 1973--- SET IN THE TOP OF A 8-INCH CYLINDRICAL CONCRETE MONUMENT THAT IS FLUSH WITH THE GROUND SURFACE. IT IS 101 FEET NORTHWEST OF WEST EDGE OF HILL, 59.4 FEET NORTHWEST OF A METAL WITNESS POST AND 2.5 FEET SOUTHEAST OF A PIPE WITNESS POST. AZIMUTH MARK IS A STANDARD DISK STAMPED ---BREA 1938 1958--- CEMENTED IN A DRILL HOLE IN A 3X3 FOOT BEDROCK SLAB THAT PROJECTS 4 INCHES ABOVE THE GROUND SURFACE. IT IS 78 FEET SOUTH OF SOUTH ONE OF TWO POWERLINE POLES, 70 FEET EAST OF APPROXIMATE CENTER OF OILED ROAD, 50.5 FEET EAST OF METAL WITNESS POST AND 20 FEET LOWER THAN ROADBED.
01/01/1977 by CADT (GOOD)
RECOVERY NOTE BY CALTRANS 1977 (ARA) THE STATION MARK, REFERENCE MARK NO. 3 AND BREA A6A RM 3 1972 WERE RECOVERED IN GOOD CONDITION IN SEPTEMBER OF 1976. REFERENCE MARK NO. 2 HAD BEEN DESTROYED BY GRADING. REFERENCE MARK NO. 4 WAS SET AT THIS TIME. THE SITE WAS REVISITED IN JUNE OF 1977. AT THIS TIME REFERENCE MARK NO. 3 WAS FOUND DESTROYED BY VANDALISM. THE AZIMUTH MARK WAS RECOVERED IN GOOD CONDITION. A NEW AND COMPLETE DESCRIPTION FOLLOWS. THE STATION IS LOCATED ON A ROUND TOPPED HILL 4 MILES NORTHEAST OF LA HABRA, 3 MILES NORTH OF BREA, AND 1/4 MILE EAST OF AN ABANDONED NIKE MISSLE SITE ON SHELL OIL COMPANY PROPERTY. PRIOR TO OCCUPATION CONTACT AUGIE NIETO AT 714-529-2478. TO REACH THE STATION FROM THE POST OFFICE AT 101 SOUTH BREA BOULEVARD IN BREA GO NORTH ON BREA BOULEVARD FOR 1.0 MILE TO CENTRAL AVENUE. TURN LEFT ON CENTRAL AVENUE AND GO 0.5 MILE TO SITE DRIVE. TURN RIGHT ON SITE DRIVE AND GO 1.0 MILE TO A METAL GATE AND THE ENTRANCE ROAD INTO THE OIL FIELDS PASS THROUGH GATE AND GO 50 FEET TO A FORK. BEAR LEFT, NORTHEAST, AND GO 0.15 MILE TO A FIVE WAY INTERSECTION. TURN HARD LEFT, WEST, AND GO 0.55 MILE TO A CATTLE GUARD AND A SIDE ROAD RIGHT. PASS THROUGH CATTLE GUARD AND GO 1.6 MILES WEST, CIRCLING TO THE EAST, TO AN OIL WELL ON THE RIGHT MARKED---PUENTE B 30---. CONTINUE STRAIGHT AND GO 0.15 MILE TO A CATTLE GUARD. PASS THROUGH CATTLE GUARD AND GO 0.2 MILE TO A FORK. BEAR LEFT, NORTHEAST, AND GO 0.4 MILE TO A CATTLE GUARD. CONTINUE STRAIGHT THROUGH CATTLE GUARD AND GO 0.55 MILE TO A FORK NEAR AN ABANDONED NIKE SITE. TURN RIGHT, EAST, AND GO 0.2 MILE TO A DIRT SIDE ROAD RIGHT. BEAR RIGHT AND GO 0.15 MILE TO THE TOP OF A HILL AND THE STATION. THE STATION MARK IS A STANDARD U.S.C AND G.S. DISK STAMPED---BREA 1938---SET IN A CONCRETE MONUMENT THAT IS 8 INCHES BELOW THE GROUND SURFACE AND COVERED BY A CAST IRON LID MARKED---COUNTY ENGINEER MONUMENT---. IT IS 60 FEET SOUTH OF THE HIGHEST POINT OF THE HILL AND 20 FEET NORTH OF THE CENTER OF A DIRT ROAD. REFERENCE MARK (LAC) 3 IS A STANDARD LOS ANGELES COUNTY DISK STAMPED ---BREA A6A RM 3 1972---SET IN THE TOP OF AN 8 INCH DIAMETER CONCRETE MONUMENT THAT IS FLUSH WITH THE GROUND SURFACE. IT IS 35 FEET SOUTH OF THE CENTER OF A DIRT ROAD, 135 FEET SOUTH OF THE HIGHEST POINT OF THE HILL, AND 3 FEET LOWER THAN THE STAION MARK. REFERENCE MARK NO. 4 IS A STANDARD CALIFORNIA DIVISION OF HIGHWAYS (CADH) DISK STAMPED---BREA NO 4 1938 1976---SET IN A 12 INCH SQUARE CONCRETE MONUMENT THAT PROJECTS 3 INCHES ABOVE THE GROUND. IT IS 48 FEET NORTHEAST OF THE CENTER OF A DIRT ROAD AND IS THE SAME ELEVATION AS THE STATION MARK. THE AZIMUTH MARK IS A STANDARD U.S.C. AND G.S. DISK STAMPED---BREA 1938 1958---CEMENTED IN A DRILL HOLE IN A 3 FOOT BY 3 FOOT ROCK OUTCROPPING THAT PROJECTS 3 INCHES ABOVE THE GROUND. IT IS 78 FEET SOUTH OF THE SOUTH ONE OF TWO POWER POLES, 70 FEET EAST OF THE CENTER OF AN OILED ROAD, 50.5 FEET EAST OF A METAL WITNESS POST, AND 20 FEET LOWER THAN THE ROAD.
03/15/1988 by PSOMAS (GOOD)
RECOVERY NOTE BY PSOMAS AND ASSOCIATES 1988 THE STATION IS LOCATED IN THE NORTHEASTERN PART OF ORANGE COUNTY. TO REACH THE STATION FROM THE INTERSECTION OF CENTRAL AVENUE AND SITE DRIVE. GO 0.6 MILE NORTHERLY TO A METAL GATE, CONTINUE NORTHWESTERLY 0.5 MILES ALONG A PAVED ROAD TO A METAL GATE AND TO A FIVE WAY INTERSECTION, BEAR LEFT ALONG A PAVED ROAD AND GO 2.4 MILES TO A FORK, BEAR LEFT ALONG A PAVED ROAD AND GO 1.1. MILES TO A FORK NEAR AN ABANDONDED NIKE SITE, TURN RIGHT AND GO EAST 0.2 MILES TO A SIDE DIRT ROAD, BEAR RIGHT AN GO 0.15 MILE TO THE TOP OF HILL AND STATION. THE STATION MARK IS A STANDARD USCGS DISK STAMPED --- BREA 1938 --- SET IN A MONUMENT BOX 8 INCHES BELOW GROUND LEVEL. THE LID OF THE MONUMERNT BOX IDENTIFIES THE MARK AS A COUNTY ENGINEER MONUMENT. THE STATION IS 60 FEET SOUTH OF THE HIGHEST POINT OF THE HILL AND 20 FEET NORTH OF THE CENTER OF A DIRT ROAD. CONTACT DON KNUFFEL, PRODUCTION FOREMAN FOR PERMISSION TO ENTER SITE AND TO OBTAIN KEY TO LOCKED GATE, TEL. 714-528-7076. REFERENCE MARK RM IS THE STEM OF A BRASS DISK SET IN A 12 INCH SQUARE CONCRETE MONUMENT. THE STATION IS NORTHERLY 56.615 FEET FROM RM. REFERENCE MARK 3 IS A STANDARD LOS ANGELES COUNTY DISK STAMPED --- BREA A6A 1972 ---, SET IN A, 8 INCH CONCRETE MONUMENT FLUSH WITH THE GROUND. IT IS 35 FEET SOUTH OF THE CENTER OF A DIRT ROAD, 135 FEET SOUTH OF THE HIGHEST POINT OF HILL AND 3 FEET LOWER THAN THE STATION MARK. RM 3 IS SOUTHERLY 71.83 FROM THE STATION. REFERENCE MARK 4 IS A STANDARD LOS ANGELES COUNTY DISK STAMPED ---BREA A6A 1972---, SET IN A 12 INCH CONCRETE MONUMENT FLUSH WITH THE GROUND. RM 4 IS EASTERLY 48.14 FEET FTOM THE STATION.
10/17/1991 by CADT (GOOD)
RECOVERY NOTE BY CALTRANS 1991 (UNK) RECOVERED IN GOOD CONDITION.
10/16/1992 by CADT (GOOD)
RECOVERY NOTE BY CALTRANS 1992 THE RECOVERY WAS ADEQUATE WITH THE FOLLOWING ADDITION. THIS STATION WAS OCCUPIED AS PART OF A CALIFORNIA HPGN DENSIFICATION SURVEY.

Control Text

  • The horizontal coordinates were established by GPS observations and adjusted by the National Geodetic Survey in June 1996. The horizontal coordinates are valid at the epoch date displayed above. The epoch date for horizontal control is a decimal equivalence of Year/Month/Day.
  • The orthometric height was determined by GPS observations and a high-resolution geoid model.
  • The X, Y, and Z were computed from the position and the ellipsoidal ht.
  • The Laplace correction was computed from DEFLEC99 derived deflections.
  • The ellipsoidal height was determined by GPS observations and is referenced to NAD 83.
  • The geoid height was determined by GEOID99.

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