Bench Mark Sheet for 8638901, CBBT, Chesapeake Channel 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Superseded Epoch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Small blue map location marker Unpublished bench mark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  5

                                                                                
Station ID: 8638901                         PUBLICATION DATE:  10/30/2020
Name:       CBBT, CHESAPEAKE CHANNEL                          
            VA
NOAA Chart: 12254                           Latitude:   37°  2.0' N (  37.03290)
USGS Quad:  CAPE HENRY                      Longitude:  76°  5.0' W ( -76.08330)


To reach the tidal bench marks from the toll booth on the south end of
Chesapeake Bay Bridge Tunnel (CBBT) in Virginia Beach, proceed north on U.S.
Highway 13 for 8 km (4.3 mi) to the south entrance of the Thimble Shoal Tunnel.
The bench marks are located on the south bound road and the third island.


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


                 PRIMARY BENCH MARK STAMPING:  8901 A 2016
                         DESIGNATION:          863 8901 A

MONUMENTATION:           Bench Mark disk                       VM#:        22482
AGENCY:                  NOS                                   IDB PID:         
SETTING CLASSIFICATION:  Building foundation                   OPUS PID:        
LATITUDE:   37°  2.2' N (  37.03656)          LONGITUDE:  76°  4.6' W ( -76.07666)


The primary bench mark is a NOS disk located on the Chesapeake Bay Bridge Tunnel
third island, set in the foundation of a vent building on the NW facing wall,
26.5 m (86.9 ft) SW of the corner of the vent building, 24.6 m (80.7 ft) SE of
the northwest facing sea wall, and 5.4 m (17.7 ft) NE of the west corner of the
vent building.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  2 of  5

                                                                                
Station ID: 8638901                         PUBLICATION DATE:  10/30/2020
Name:       CBBT, CHESAPEAKE CHANNEL                          
            VA
NOAA Chart: 12254                           Latitude:   37°  2.0' N (  37.03290)
USGS Quad:  CAPE HENRY                      Longitude:  76°  5.0' W ( -76.08330)


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


                         BENCH MARK STAMPING:  8901 B 2016
                         DESIGNATION:          863 8901 B

MONUMENTATION:           Bench Mark disk                       VM#:        22483
AGENCY:                  NOS                                   IDB PID:         
SETTING CLASSIFICATION:  Retaining wall                        OPUS PID:        
LATITUDE:   37°  2.2' N (  37.03603)          LONGITUDE:  76°  4.7' W ( -76.07783)


The bench mark is a NOS brass disk located on the Chesapeake Bay Bridge Tunnel
on the third island set on the northwest corner of the seawall, 59.2 m (194.2
ft) SW of the light pole closest to the vent building, 43.7 m (143.4 ft) north
of the light pole second closest to the vent building, 24.6 m (80.7 ft) NW of
the northwest facing tunnel wall, and 0.4 m (1.3 ft) SE of the northwest face of
the seawall.



                         BENCH MARK STAMPING:  8901 C 2016
                         DESIGNATION:          863 8901 C

MONUMENTATION:           Bench Mark disk                       VM#:        22484
AGENCY:                  NOS                                   IDB PID:         
SETTING CLASSIFICATION:  Retaining wall                        OPUS PID:        
LATITUDE:   37°  2.1' N (  37.03486)          LONGITUDE:  76°  4.8' W ( -76.07939)


The bench mark is a NOS brass disk set in the Chesapeake Bay Bridge Tunnel on
the third island and is set in the corner of the NW facing massive concrete
retaining wall, 74.3 m (243.8 ft) NE of the west corner of the seawall, 25.4 m
(83.3 ft) north of the light pole located at tunnel entrance, 12.6 m (41.3 ft)
NW of the northeast facing tunnel wall, and 7.2 m (23.6 ft) SE of the northwest
facing sea wall.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  3 of  5

                                                                                
Station ID: 8638901                         PUBLICATION DATE:  10/30/2020
Name:       CBBT, CHESAPEAKE CHANNEL                          
            VA
NOAA Chart: 12254                           Latitude:   37°  2.0' N (  37.03290)
USGS Quad:  CAPE HENRY                      Longitude:  76°  5.0' W ( -76.08330)


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


                         BENCH MARK STAMPING:   
                         DESIGNATION:          99

MONUMENTATION:           Bench Mark disk                       VM#:        22485
AGENCY:                                                        IDB PID:         
SETTING CLASSIFICATION:  Retaining wall                        OPUS PID:        
LATITUDE:   37°  2.2' N (  37.03639)          LONGITUDE:  76°  4.6' W ( -76.07722)






                         BENCH MARK STAMPING:   
                         DESIGNATION:          78

MONUMENTATION:           Bench Mark disk                       VM#:        22486
AGENCY:                                                        IDB PID:         
SETTING CLASSIFICATION:  Retaining wall                        OPUS PID:        
LATITUDE:   37°  2.2' N (  37.03672)          LONGITUDE:  76°  4.6' W ( -76.07631)




                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  4 of  5

                                                                                
Station ID: 8638901                         PUBLICATION DATE:  10/30/2020
Name:       CBBT, CHESAPEAKE CHANNEL                          
            VA
NOAA Chart: 12254                           Latitude:   37°  2.0' N (  37.03290)
USGS Quad:  CAPE HENRY                      Longitude:  76°  5.0' W ( -76.08330)


                            T I D A L   D A T U M S 


Tidal datums at CBBT, CHESAPEAKE CHANNEL based on:

     LENGTH OF SERIES:      2 YEARS
     TIME PERIOD:           September 2017 - August 2019
     TIDAL EPOCH:           1983-2001
     CONTROL TIDE STATION:  8632200 KIPTOPEKE, CHESAPEAKE BAY


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

     HIGHEST OBSERVED WATER LEVEL (09/06/2019)         =  1.904
     MEAN HIGHER HIGH WATER                     MHHW   =  0.919
     MEAN HIGH WATER                            MHW    =  0.846
     MEAN SEA LEVEL                             MSL    =  0.449
     MEAN TIDE LEVEL                            MTL    =  0.441
     MEAN LOW WATER                             MLW    =  0.036
     MEAN LOWER LOW WATER                       MLLW   =  0.000
     LOWEST  OBSERVED WATER LEVEL (01/06/2018)         = -0.505



Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MLLW        MHW

     8901 A 2016                                 8.645    7.799
     8901 B 2016                                 8.152    7.306
     8901 C 2016                                 8.086    7.240
     99                                          8.135    7.289
     78                                          8.186    7.340


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

                                                                                
Station ID: 8638901                         PUBLICATION DATE:  10/30/2020
Name:       CBBT, CHESAPEAKE CHANNEL                          
            VA
NOAA Chart: 12254                           Latitude:   37°  2.0' N (  37.03290)
USGS Quad:  CAPE HENRY                      Longitude:  76°  5.0' W ( -76.08330)


                             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.

Return to Top
Products available at 8638901 CBBT, Chesapeake Channel, VA