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Bench Mark Sheet for 8655353, Portsmouth NC

Superseded Epoch

Large map location marker Station Location
Small red map location marker Published bench mark
Small blue map location marker Unpublished bench mark

Bench mark positions only appear on the map if their coordinates in the CO-OPS database are at the precision of degrees/minutes/seconds/and tenths of seconds. If the coordinates are less precise, the mark will not appear.

Printable version

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
Datums Page                                                        Page  1 of  7

                                                                                
Station ID: 8655353                         PUBLICATION DATE:  01/29/2013
Name:       PORTSMOUTH                                        
            NC
NOAA Chart: 11550                           Latitude:   34° 58.8' N (  34.97939)
USGS Quad:  WAINWRIGHT ISLAND               Longitude:  76°  9.8' W ( -76.16308)


To reach the tidal bench marks with a 4 wheel drive vehicle from the
intersection of Highway 12 and Highway 70 near Sealevel, North Carolina, proceed
southeast then east on Hwy 70 (Seashore Drive) for 7.2 km (4.5 mi) to School
Drive, turn left onto School Drive and proceed northwest for 0.4 km (0.2 mi) to
its intersection with Shell Road, turn right on Shell Road and proceed northeast
for 1.0 km (0.6 mi) to its intersection with Core Sound Loop Road and Morris
Marina Road, proceed straight onto Morris Marina road continuing NE for 1.3 km
(0.8 mi) to its termination at the Morris Marina parking lot.  Board the ferry
and continue east 6.1 km (3.8 mi) or 45 minutes to the ferry landing area at the
National Park Service Long Point cabin area on Portsmouth Island, disembark the
ferry and continue southeast on sand road for 0.2 km (0.1 mi) to beach ramp
number 16, turn left and proceed northeast on the beach for 12.9 km (8.0 mi) to
beach ramp number 9, turn left and proceed north-northwest on sand track for 0.3
km (0.2 mi) to its termination and a cul-de-sac.  The bench marks are located
along the sand track and across the slough to the northwest.  The tide gauge is
located across the slough to the northwest.  


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


                 PRIMARY BENCH MARK STAMPING:  5353 C 2012
                         DESIGNATION:          865 5353 C

MONUMENTATION:           Metal Rod                             VM#:        20418
AGENCY:                  NOS                                   IDB PID#:        
SETTING CLASSIFICATION:  Flange-encased rod                    OPUS PID:        
LATITUDE:   34° 58.7' N (  34.97914)          LONGITUDE:  76°  9.8' W ( -76.16325)


The primary bench mark is a flange-encased rod located along the eastern edge of
junipers west of the slough, 27.60 m (90.6 ft) northeast of the base of a large
cedar tree, 24.10 m (79.1 ft) southwest of the edge of the slough bank, 1.12 m
(3.7 ft) northeast of an orange carsonite NOS witness post and 0.68 m (2.2 ft)
west-southwest of a pressure treated 4x4 wooden post projecting 0.33 m (1.1 ft)
above grade.  The datum point is set 13 cm (5 inches) below grade, being the top
of a stainless steel rod driven 24.4 m (80.1 ft) to refusal, in a sleeve
extending to a depth of 0.9 m (3.0 ft) and encased in a 5-inch (13 cm) National
Geodetic Survey logo cap with concrete kickblock.  

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  2 of  7

                                                                                
Station ID: 8655353                         PUBLICATION DATE:  01/29/2013
Name:       PORTSMOUTH                                        
            NC
NOAA Chart: 11550                           Latitude:   34° 58.8' N (  34.97939)
USGS Quad:  WAINWRIGHT ISLAND               Longitude:  76°  9.8' W ( -76.16308)


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


                         BENCH MARK STAMPING:  5353 B 2012
                         DESIGNATION:          865 5353 B

MONUMENTATION:           Metal Rod                             VM#:        20419
AGENCY:                  NOS                                   IDB PID#:        
SETTING CLASSIFICATION:  Flange-encased rod                    OPUS PID#: BBCS62
LATITUDE:   34° 58.7' N (  34.97850)          LONGITUDE:  76°  9.7' W ( -76.16136)


The bench mark is a flange-encased rod located in juniper bushes north of a sand
parking area, 21.62 m (70.9 ft) east-northeast of the east bank of the slough,
8.02 m (26.3 ft) north of the center of the parking area, 4.35 m (14.3 ft)
east-northeast of the prolongation of the centerline of the access road from the
beach, 1.13 m (3.7 ft) south-southwest of an orange carsonite NOS witness post
and 1.12 m (3.7 ft) south of a wooden post and sign with the letter p for
parking.  The datum point is set 10 cm (4 inches) below grade, being the top of
a stainless steel rod driven 23.1 m (75.8 ft) to refusal, in a sleeve extending
to a depth of 0.9 m (3.0 ft) and encased in a 5-inch (13 cm) National Ocean
Service logo cap with concrete kickblock.  

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  3 of  7

                                                                                
Station ID: 8655353                         PUBLICATION DATE:  01/29/2013
Name:       PORTSMOUTH                                        
            NC
NOAA Chart: 11550                           Latitude:   34° 58.8' N (  34.97939)
USGS Quad:  WAINWRIGHT ISLAND               Longitude:  76°  9.8' W ( -76.16308)


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


                         BENCH MARK STAMPING:  5353 A 2012
                         DESIGNATION:          865 5353 A

MONUMENTATION:           Metal Rod                             VM#:        20420
AGENCY:                  NOS                                   IDB PID#:        
SETTING CLASSIFICATION:  Flange-encased rod                    OPUS PID#: BBCS61
LATITUDE:   34° 58.5' N (  34.97556)          LONGITUDE:  76°  9.7' W ( -76.16131)


The bench mark is a flange-encased rod located in a cluster of juniper bushes on
the north side of a sand jeep trail, 86.93 m (285.2 ft) north-northeast of a
sign with a graphic of a crossed-out jeep, 79.90 m (262.1 ft) west-southwest of
a sign with a graphic of a jeep, 29.72 m (97.5 ft) west-northwest of a sign with
a graphic of a jeep, 27.05 m (88.7 ft) north-northwest of the centerline of the
sand jeep trail, 11.61 m (38.1 ft) north-northwest of an orange carsonite NOS
witness post and 0.78 m (2.6 ft) north-northwest of a second orange carsonite
NOS witness post.  The datum point is set 11 cm (4 inches) below grade, being
the top of a stainless steel rod driven 23.1 m (75.8 ft) to refusal, in a sleeve
extending to a depth of 0.9 m (3.0 ft) and encased in a 5-inch (13 cm) National
Geodetic Survey logo cap with concrete kickblock. 

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  4 of  7

                                                                                
Station ID: 8655353                         PUBLICATION DATE:  01/29/2013
Name:       PORTSMOUTH                                        
            NC
NOAA Chart: 11550                           Latitude:   34° 58.8' N (  34.97939)
USGS Quad:  WAINWRIGHT ISLAND               Longitude:  76°  9.8' W ( -76.16308)


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


                         BENCH MARK STAMPING:  CALO 02 2010
                         DESIGNATION:          CALO 02 2010

MONUMENTATION:           Metal Rod                             VM#:        20421
AGENCY:                  National Park Service                 IDB PID#:        
SETTING CLASSIFICATION:                                        OPUS PID:        
LATITUDE:   34° 58.4' N (  34.97327)          LONGITUDE:  76°  9.8' W ( -76.16402)


To reach from the National Park Service long point ferry landing proceed
southeast on dirt road to long point camp east for 0.06 mi (0.1 km) to fork in
sand road known as back road.  Take left fork of back road and proceed north for
7.01 mi (11.3 km) to beach access ramp 10A.  Continue north along back road
north for 0.35 mi (0.6 km) to the station set flush with the ground.   The
station is also south 0.32 mi (0.5 km) along back road from beach access ramp 9.
 Located 55.30 ft (16.9 m) northwest of the centerline of back road, 43.32 ft
(13.2 m) south of another 4 inch (10 cm) treated wooden post with a NCGS
reference tag,  3.09 ft (0.9 m) south of a 4 inch (10 cm) treated wooden post
with NCGS reference tag, treated wooden posts are in line to the north of
station. Note - Magnetic properties are a bolt set on north side of monument.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  5 of  7

                                                                                
Station ID: 8655353                         PUBLICATION DATE:  01/29/2013
Name:       PORTSMOUTH                                        
            NC
NOAA Chart: 11550                           Latitude:   34° 58.8' N (  34.97939)
USGS Quad:  WAINWRIGHT ISLAND               Longitude:  76°  9.8' W ( -76.16308)


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


                         BENCH MARK STAMPING:  USE
                         DESIGNATION:          USE

MONUMENTATION:           Survey disk                           VM#:        20422
AGENCY:                                                        IDB PID#:        
SETTING CLASSIFICATION:                                        OPUS PID:        
LATITUDE:   34° 58.7' N (  34.97881)          LONGITUDE:  76°  9.8' W ( -76.16371)


The bench mark is a disk set on top of a 0.20 m (0.7 ft) x 0.19 m (0.6 ft)
concrete block surrounded by dense juniper bushes, 12.12 m (39.8 ft) southeast
of bench mark swash no 1, 1.3 m (4.3 ft) west-southwest of a fallen cypress tree
and 0.15 m (0.5 ft) southwest from an orange carsonite National Ocean Service
witness post. Described by Coast and Geodetic Survey 1960.        

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  6 of  7

                                                                                
Station ID: 8655353                         PUBLICATION DATE:  01/29/2013
Name:       PORTSMOUTH                                        
            NC
NOAA Chart: 11550                           Latitude:   34° 58.8' N (  34.97939)
USGS Quad:  WAINWRIGHT ISLAND               Longitude:  76°  9.8' W ( -76.16308)


                            T I D A L   D A T U M S 


Tidal datums at PORTSMOUTH based on:

     LENGTH OF SERIES:      3 MONTHS
     TIME PERIOD:           May 2012 - July 2012
     TIDAL EPOCH:           1983-2001
     CONTROL TIDE STATION:  8654467 USCG STATION HATTERAS, PAMLICO SOUND


Elevations of tidal datums referred to Mean Sea Level (MSL), in METERS:

     MEAN SEA LEVEL                             MSL    =  0.000

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                                MSL

     5353 C 2012                                          0.641
     5353 B 2012                                          0.412
     5353 A 2012                                          1.830
     CALO 02 2010                                         1.409
     USE                                                  0.816


Foot Notes:

This station has been determined to be Non-tidal for tidal datum purposes. There
is either no measureable periodic rise and fall of the tide at this location, or
it may be present but inconsistent, or the periodic tide is present and
consistent, however the Mean Range of Tide (MN) is negligible, that is below the
established tidal/non-tidal threshold of 0.03m (0.10ft). Only the datum of local
Mean Sea Level (MSL) is published at these stations. For Nautical Charting Datum
applications, a non-tidal Low Water Datum (LWD) is established as 0.50ft (0.15m)
below MSL.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  7 of  7

                                                                                
Station ID: 8655353                         PUBLICATION DATE:  01/29/2013
Name:       PORTSMOUTH                                        
            NC
NOAA Chart: 11550                           Latitude:   34° 58.8' N (  34.97939)
USGS Quad:  WAINWRIGHT ISLAND               Longitude:  76°  9.8' W ( -76.16308)


                             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 NGS's Integrated Data Base (IDB PID)
provides geodetic datum based on traditionally leveled and bluebooked ties to
the National Spatial Reference System(NSRS) https://www.ngs.noaa.gov/datasheets/.
The NGS Online Positioning User Service (OPUS PID) provides geodetic datum based
on GPS position & tie it to the NSRS https://www.ngs.noaa.gov/OPUS/.

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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Products available at 8655353 Portsmouth, NC

Revised: 08/08/2018
NOAA / National Ocean Service
Web site owner: Center for Operational Oceanographic Products and Services