Superseded Bench Mark Sheet for 8652678, USCG LIFEBOAT STATION, OREGON INLET NC

Present Epoch

Printable version

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
Datums Page                                                        Page  1 of  4

                                                   PUBLICATION DATE:  10/23/2000
Station ID: 8652678                                SUPERCEDED DATE:   04/21/2003
Name:       USCG LIFEBOAT STATION, OREGON INLET               
            NORTH CAROLINA
NOAA Chart: 12204                                  Latitude:         35° 46.1' N
USGS Quad:  OREGON INLET                           Longitude:        75° 31.6' W


To reach the tidal bench marks at the old Coast Guard Station at Oregon Inlet,
NC, from the State Route 12 bridge over Oregon Inlet, proceed to the SE end of
the bridge and a parking area on the east side of the highway, then continue on
foot along the shoreline to the abandoned Coast Guard Lifeboat Station.  The
bench marks are located on the grounds of the station.  The tide gage and staff
were located on a small abandoned pier formerly used by the Coast Guard.


                         T I D A L   B E N C H   M A R K S


                 PRIMARY BENCH MARK STAMPING:  NO 2 1974
                         DESIGNATION:          TIDAL 2

MONUMENTATION:           Tidal Station disk                        VM#:    12576
AGENCY:                  National Ocean Survey (NOS)               PID#:  EX0158
SETTING CLASSIFICATION:  Concrete step


The primary bench mark is a disk set flush in the SE corner of the concrete step
of the generator building, 22.25 m ( 73.0 ft) SW of the NW corner of the station
house, and 1.31 m (4.3 ft) east of the SE corner of the generator building.



                         BENCH MARK STAMPING:  NO 1 1974
                         DESIGNATION:          TIDAL 1

MONUMENTATION:           Tidal Station disk                        VM#:      270
AGENCY:                  National Ocean Survey (NOS)               PID#:  EX0154
SETTING CLASSIFICATION:  Concrete ramp


The bench mark is a disk set flush in a concrete garage ramp, 21.64 m (71.0 ft)
south of where the pier and bulkhead join, and 3.96 m (13.0 ft) west of the NE
corner of the garage.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  2 of  4

                                                   PUBLICATION DATE:  10/23/2000
Station ID: 8652678                                SUPERCEDED DATE:   04/21/2003
Name:       USCG LIFEBOAT STATION, OREGON INLET               
            NORTH CAROLINA
NOAA Chart: 12204                                  Latitude:         35° 46.1' N
USGS Quad:  OREGON INLET                           Longitude:        75° 31.6' W


                         T I D A L   B E N C H   M A R K S


                         BENCH MARK STAMPING:  NO 3 1962
                         DESIGNATION:          TIDAL 3

MONUMENTATION:           Tidal Station disk                        VM#:    12661
AGENCY:                  National Ocean Survey (NOS)               PID#:  EX0159
SETTING CLASSIFICATION:  Concrete porch


The bench mark is a disk set in the NNW corner of the concrete porch at the back
of the Coast Guard Station House, 6.83 m (22.4 ft) north of the south corner of
the porch, and 1.55 m (5.1 ft) west of the steps to the back entrance.



                         BENCH MARK STAMPING:  NO 4 1974
                         DESIGNATION:          TIDAL 4

MONUMENTATION:           Tidal Station disk                        VM#:    12662
AGENCY:                  National Ocean Survey (NOS)               PID#:  EX0157
SETTING CLASSIFICATION:  Concrete deck


The bench mark is a disk set flush in a concrete deck, 25.30 m (83.0 ft) north
of the generator building, 14.60 m (47.9 ft) west of the NW corner of the
station house, 12.19 m (40.0 ft) east of the NW corner of a chain link fence,
and 0.09 m (0.3 ft) south of the north edge of the concrete deck.



                         BENCH MARK STAMPING:   
                         DESIGNATION:          865 2678 NO STAMPING 1

MONUMENTATION:           Chiseled Square                           VM#:    12663
AGENCY:                  National Ocean Service (NOS)              PID:         
SETTING CLASSIFICATION:  Concrete step


The bench mark is a chiseled square in the lowest of three steps that lead to
the old Coast Guard Pier, 24.48 m (80.3 ft) north of the NE corner of the garage
building, 13.11 m (43.0 ft) SSW of the SW side of the boat ramp, 9.45 m (31.0
ft) SE of the SE end of the pier, and 0.15 m (0.5 ft) above ground.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  3 of  4

                                                   PUBLICATION DATE:  10/23/2000
Station ID: 8652678                                SUPERCEDED DATE:   04/21/2003
Name:       USCG LIFEBOAT STATION, OREGON INLET               
            NORTH CAROLINA
NOAA Chart: 12204                                  Latitude:         35° 46.1' N
USGS Quad:  OREGON INLET                           Longitude:        75° 31.6' W


                            T I D A L   D A T U M S 


Tidal datums at USCG LIFEBOAT STATION, OREGON INLET based on:

     LENGTH OF SERIES:      4 MONTHS
     TIME PERIOD:           April 1994 - July 1994
     TIDAL EPOCH:           1960-1978
     CONTROL TIDE STATION:  8652587 OREGON INLET MARINA


Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:

     MEAN HIGHER HIGH WATER                     MHHW   =  0.675
     MEAN HIGH WATER                            MHW    =  0.610
     North American Vertical Datum              NAVD88 =  0.552
     MEAN TIDE LEVEL                            MTL    =  0.319
     MEAN SEA LEVEL                             MSL    =  0.316
     MEAN LOW WATER                             MLW    =  0.027
     MEAN LOWER LOW WATER                       MLLW   =  0.000

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MLLW        MHW

     NO 2 1974                                   2.200    1.590
     NO 1 1974                                   1.848    1.238
     NO 3 1962                                   2.365    1.755
     NO 4 1974                                   1.869    1.259
     865 2678 NO STAMPING 1                      1.383    0.773


                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  4 of  4

                                                   PUBLICATION DATE:  10/23/2000
Station ID: 8652678                                SUPERCEDED DATE:   04/21/2003
Name:       USCG LIFEBOAT STATION, OREGON INLET               
            NORTH CAROLINA
NOAA Chart: 12204                                  Latitude:         35° 46.1' N
USGS Quad:  OREGON INLET                           Longitude:        75° 31.6' W


                             D E F I N I T I O N S


Mean Sea Level (MSL) is a tidal datum determined over a 19-year National Tidal
Datum Epoch.  It pertains to local mean sea level and should not be confused
with the fixed datums of North American Vertical Datum of 1988 (NAVD88).

NAVD88 is a fixed datum derived from a simultaneous, least squares, minimum
constraint adjustment of Canadian/Mexican/United States leveling observations.
Local mean sea level observed at Father Point/Rimouski, Canada was held fixed as
the single initial constraint.  NAVD88 replaces NGVD29 as the national
standard geodetic reference for heights.  Bench mark elevations relative to
NAVD88 are available from NGS through the World Wide Web at 
National Geodetic Survey.

NGVD29 is a fixed datum adopted as a national standard geodetic reference for
heights but is now considered superseded.  NGVD29 is sometimes referred to as
Sea Level Datum of 1929 or as Mean Sea Level on some early issues of Geological
Survey Topographic Quads.  NGVD29 was originally derived from a general
adjustment of the first-order leveling networks of the U.S. and Canada after
holding mean sea level observed at 26 long term tide stations as fixed.
Numerous local and wide-spread adjustments have been made since establishment in
1929.  Bench mark elevations relative to NGVD29 are available from the National
Geodetic Survey (NGS) data base via the World Wide Web at 
National Geodetic Survey.

NAVD88 and NGVD29 are fixed geodetic datums whose elevation relationships to
local MSL and other tidal datums may not be consistent from one location to
another.

The Vertical Mark Number (VM#) and PID# shown on the bench mark sheet are unique
identifiers for bench marks in the tidal and geodetic databases, respectively.
Each bench mark in either database has a single, unique VM# and/or PID# assigned.
Where both VM# and PID# are indicated, both tidal and geodetic elevations are
available for the bench mark listed.

The NAVD88 elevation is shown on the Elevations of Tidal Datums Table Referred
to MLLW only when two or more of the bench marks listed have NAVD88 elevations.
The NAVD88 elevation relationship shown in the table is derived from an average
of several bench mark elevations relative to tide station datum.  As a result of
this averaging, NAVD88 bench mark elevations computed indirectly from the tidal
datums elevation table may differ slightly from NAVD88 elevations listed for
each bench mark in the NGS database.

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