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Bench Mark Sheet for 8638449, CLAREMONT, JAMES RIVER VA

Superseded Epoch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Small blue map location marker Unpublished bench mark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  6

                                                                                
Station ID: 8638449                         PUBLICATION DATE:  04/29/2003
Name:       CLAREMONT, JAMES RIVER                            
            VA
NOAA Chart: 12251                           Latitude:   37° 13.9' N (  37.23170)
USGS Quad:  CLAREMONT                       Longitude:  76° 56.9' W ( -76.94830)


To reach the tidal bench marks from the Claremont Post Office, proceed east on
County Road T 613 for 1.1 km (0.7 mi) and then SE on County Road T 1202 for 0.3
km (0.2 mi) to the circle at the end of the road.  The bench marks are near the
center of the circle at the end of the road, and along the south bank of James
River.  The tide gage and staff were at the NE end of an abandoned Navy pier.


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


                 PRIMARY BENCH MARK STAMPING:  BM 6 1951
                         DESIGNATION:          863 8449 BM 6

MONUMENTATION:           Tidal Station disk                    VM#:         3456
AGENCY:                  US Coast and Geodetic Survey
                         (USC&GS)                              IDB PID#:        
SETTING CLASSIFICATION:  Water tower foundation                OPUS PID:        
LATITUDE:   37° 13.9' N (  37.23170)          LONGITUDE:  76° 56.9' W ( -76.94830)


The primary bench mark is a disk set in the SW corner of the westernmost of the
two northern concrete foundations of the legs of the water tower located about
midway between the abandoned Navy pier and the Claremont-Sandy Point ferry slip,
6.1 m (20 ft) east of the property line fence at the gate, and 0.3 m (1 ft)
above ground level.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  2 of  6

                                                                                
Station ID: 8638449                         PUBLICATION DATE:  04/29/2003
Name:       CLAREMONT, JAMES RIVER                            
            VA
NOAA Chart: 12251                           Latitude:   37° 13.9' N (  37.23170)
USGS Quad:  CLAREMONT                       Longitude:  76° 56.9' W ( -76.94830)


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


                         BENCH MARK STAMPING:  NO 7 1970
                         DESIGNATION:          TIDAL 7 STA 81

MONUMENTATION:           Tidal Station disk                    VM#:         3457
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:  GV0448
SETTING CLASSIFICATION:  Boat ramp                             OPUS PID:        
LATITUDE:   37° 13.8' N (  37.23000)          LONGITUDE:  76° 57.0' W ( -76.95000)


The bench mark is a disk set in the top of the west corner of a boat ramp
leading to the James River from the garage of a concrete block house along
County Road T 1202, 30.94 m (101.5 ft) NW of Bench Mark A 453, 19.5 m (64 ft) NW
of the centerline of the road along the NW side of the circle at the end of the
road, 9.1 m (30 ft) SW of the approximate shoreline, and 0.67 m (2.2 ft) east of
the north corner of the house.



                         BENCH MARK STAMPING:  NO 8 1970
                         DESIGNATION:          863 8449 TIDAL 8

MONUMENTATION:           Tidal Station disk                    VM#:         3458
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Driveway                              OPUS PID:        
LATITUDE:   37° 13.9' N (  37.23170)          LONGITUDE:  76° 56.9' W ( -76.94830)


The bench mark is a disk set in the driveway of the seventh house  east of Bench
Mark BM 6 1951, 0.18 m (0.6 ft) from the garage door.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  3 of  6

                                                                                
Station ID: 8638449                         PUBLICATION DATE:  04/29/2003
Name:       CLAREMONT, JAMES RIVER                            
            VA
NOAA Chart: 12251                           Latitude:   37° 13.9' N (  37.23170)
USGS Quad:  CLAREMONT                       Longitude:  76° 56.9' W ( -76.94830)


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


                         BENCH MARK STAMPING:  A 453 1971
                         DESIGNATION:          A 453

MONUMENTATION:           Bench Mark disk                       VM#:         3459
AGENCY:                  National Geodetic Survey (NGS)        IDB PID#:  GV0447
SETTING CLASSIFICATION:  Copper-clad steel rod                 OPUS PID:        
LATITUDE:   37° 13.8' N (  37.23000)          LONGITUDE:  76° 57.1' W ( -76.95170)


The bench mark is a disk located near the center of a circle at the end of
County Road T 1202, 20.4 m (67 ft) SE of the east corner of a concrete block
house, 14.3 m (47 ft) NW of the centerline of the road along the SE side of the
circle, 11.3 m (37 ft) SE of the centerline of the road along the NW side of the
circle, 10.7 m (35 ft) north of a 0.6 m (2 ft) diameter oak tree, and 0.46 m
(1.5 ft) NW of a metal witness post. The bench mark is crimped to a copper-clad
steel rod driven 21.9 m (72 ft) to refusal, and encased in a 4-inch metal pipe.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  4 of  6

                                                                                
Station ID: 8638449                         PUBLICATION DATE:  04/29/2003
Name:       CLAREMONT, JAMES RIVER                            
            VA
NOAA Chart: 12251                           Latitude:   37° 13.9' N (  37.23170)
USGS Quad:  CLAREMONT                       Longitude:  76° 56.9' W ( -76.94830)


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


                         BENCH MARK STAMPING:  B 453 1971
                         DESIGNATION:          B 453

MONUMENTATION:           Bench Mark disk                       VM#:         3460
AGENCY:                  National Geodetic Survey (NGS)        IDB PID#:  GV0449
SETTING CLASSIFICATION:  Copper-clad steel rod                 OPUS PID:        
LATITUDE:   37° 13.8' N (  37.23000)          LONGITUDE:  76° 57.0' W ( -76.95000)


The bench mark is a disk located in the vicinity of the abandoned Navy pier,
118.9 m (390 ft) NE of the centerline of County Road T 1202, 80.5 m (264 ft) SE
of the center of the circle at the end of the road, 26.8 m (88 ft) north of the
north porch corner for a one story residence, 21.0 m (69 ft) SW of the SW end of
the abandoned Navy pier, 15.5 m (51 ft) SW of the approximate shoreline, and
0.46 m (1.5 ft) SW of a metal witness post.  The bench mark is crimped to a
copper-clad steel rod driven 21.6 m (71 ft) to refusal and encased in a 4-inch
steel pipe.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  5 of  6

                                                                                
Station ID: 8638449                         PUBLICATION DATE:  04/29/2003
Name:       CLAREMONT, JAMES RIVER                            
            VA
NOAA Chart: 12251                           Latitude:   37° 13.9' N (  37.23170)
USGS Quad:  CLAREMONT                       Longitude:  76° 56.9' W ( -76.94830)


                            T I D A L   D A T U M S 


Tidal datums at CLAREMONT, JAMES RIVER based on:

     LENGTH OF SERIES:      36 MONTHS
     TIME PERIOD:           February 1971 - January 1974
     TIDAL EPOCH:           1983-2001
     CONTROL TIDE STATION:  8638610 SEWELLS POINT, HAMPTON ROADS


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

     HIGHEST OBSERVED WATER LEVEL (10/06/1972)         =  1.391
     MEAN HIGHER HIGH WATER                     MHHW   =  0.647
     MEAN HIGH WATER                            MHW    =  0.589
     MEAN SEA LEVEL                             MSL    =  0.334
     MEAN TIDE LEVEL                            MTL    =  0.317
     MEAN LOW WATER                             MLW    =  0.045
     MEAN LOWER LOW WATER                       MLLW   =  0.000
     LOWEST  OBSERVED WATER LEVEL (01/27/1971)         = -0.841

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MLLW        MHW

     BM 6 1951                                   1.555    0.966
     NO 7 1970                                   1.496    0.907
     NO 8 1970                                   1.694    1.105
     A 453 1971                                  1.305    0.716
     B 453 1971                                  1.094    0.505


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

                                                                                
Station ID: 8638449                         PUBLICATION DATE:  04/29/2003
Name:       CLAREMONT, JAMES RIVER                            
            VA
NOAA Chart: 12251                           Latitude:   37° 13.9' N (  37.23170)
USGS Quad:  CLAREMONT                       Longitude:  76° 56.9' W ( -76.94830)


                             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 8638449 CLAREMONT, JAMES RIVER, VA

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