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Datums Page Page 1 of 9
Station ID: 8631044 PUBLICATION DATE: 04/26/2022
Name: WACHAPREAGUE, WACHAPREAGUE CHANNEL
VA
NOAA Chart: 12210 Latitude: 37° 36.5' N ( 37.60778)
USGS Quad: WACHAPREAGUE Longitude: 75° 41.2' W ( -75.68583)
To reach the tidal bench marks from the intersection of US Highway 13 and State
Route 180 in Keller, Virginia proceed east on State Route 180 for 7.1 km (4.4
mi) to a T intersection with Atlantic Avenue (County Road 1701). Continue north
on Atlantic Avenue for 0.6 km (0.4 mi) to the Virginia Institute of Marine
Sciences (VIMS), Eastern Shore Laboratory. The bench marks are located on the
VIMS property. The tide gauge is located behind the new VIMS building.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 1044 G 1981
DESIGNATION: 863 1044 G
MONUMENTATION: Tidal Station disk VM#: 475
AGENCY: National Ocean Survey (NOS) IDB PID#:
SETTING CLASSIFICATION: Stainless steel rod OPUS PID#: BBDL07
LATITUDE: 37° 36.5' N ( 37.60769) LONGITUDE: 75° 41.2' W ( -75.68686)
The primary bench mark is a disk located near the Virginia Game Commission pier
on the east side of Atlantic Avenue near Riverview Avenue, 21.00 m (68.9 ft)
north of the SE corner of the marine bulkhead, 11.89 m (39.0 ft) SSW of the SW
corner of a 9 m (30 ft) x 6 m (20 ft) galvanized sheet building, 7.80 m (25.6
ft) east of the centerline of Atlantic Avenue, and 0.55 m (1.8 ft) SSE of power
pole numbered 29J/317A. The bench mark is crimped to a stainless steel rod
driven 11.0 m (36 ft) to refusal, and encased in a 6-inch pvc pipe with concrete
kickblock.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 9
Station ID: 8631044 PUBLICATION DATE: 04/26/2022
Name: WACHAPREAGUE, WACHAPREAGUE CHANNEL
VA
NOAA Chart: 12210 Latitude: 37° 36.5' N ( 37.60778)
USGS Quad: WACHAPREAGUE Longitude: 75° 41.2' W ( -75.68583)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 1044 C 1978
DESIGNATION: 863 1044 C
MONUMENTATION: Tidal Station disk VM#: 471
AGENCY: National Ocean Survey (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete monument OPUS PID:
LATITUDE: 37° 36.5' N ( 37.60786) LONGITUDE: 75° 41.2' W ( -75.68672)
The bench mark is a disk located at the SW post for the Virginia Institute of
Marine Sciences sign near the Library Building, 12.25 m (40.2 ft) NNW of the
centerline of Atlantic Avenue, 10.00 m (32.8 ft) NNE of the centerline of
Riverview Avenue, 9.63 m (31.6 ft) south of the SE corner of the Library
Building, 0.21 m (0.7 ft) SE of the SW post of the sign, and 0.09 m (0.3 ft)
below ground.
BENCH MARK STAMPING: 1044 D 1978
DESIGNATION: 863 1044 D
MONUMENTATION: Tidal Station disk VM#: 472
AGENCY: National Ocean Survey (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete monument OPUS PID:
LATITUDE: 37° 36.5' N ( 37.60883) LONGITUDE: 75° 41.2' W ( -75.68708)
The bench mark is a disk located near the SE corner of the wood siding dormitory
building on the north side of Liberty Street, 15.45 m (50.7 ft) north of Light
Pole numbered 44144/65615, 9.91 m (32.5 ft) NE of the centerline of Liberty
Street, 9.39 m (30.8 ft) NNE of the centerline of Atlantic Avenue, 9.30 m (30.5
ft) NW of the NW corner of a 0.82 m x 1.52 m (2.7 ft x 5.0 ft) concrete
saltwater sump, and 1.37 m (4.5 ft) SE of the SE corner of the dormitory
building.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 9
Station ID: 8631044 PUBLICATION DATE: 04/26/2022
Name: WACHAPREAGUE, WACHAPREAGUE CHANNEL
VA
NOAA Chart: 12210 Latitude: 37° 36.5' N ( 37.60778)
USGS Quad: WACHAPREAGUE Longitude: 75° 41.2' W ( -75.68583)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 1044 E 1978
DESIGNATION: 863 1044 E
MONUMENTATION: Tidal Station disk VM#: 473
AGENCY: National Ocean Survey (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete monument OPUS PID:
LATITUDE: 37° 36.5' N ( 37.60850) LONGITUDE: 75° 41.2' W ( -75.68708)
The bench mark is a disk located near the NW corner of a brick pump house, 27.65
m (90.7 ft) SW of the centerline of Liberty Street, 13.87 m (45.5 ft) west of
the western corner of the laboratory building, 9.54 m (31.3 ft) north of the NW
corner of a barn type garage building, 0.67 m (2.2 ft) north of the northern
corner of a 2.74 m (9 ft) x 2.74 m (9 ft) brick pump house, and 0.03 m (0.1 ft)
below ground.
BENCH MARK STAMPING: 1044 F 1981
DESIGNATION: 863 1044 F
MONUMENTATION: Tidal Station disk VM#: 474
AGENCY: National Ocean Survey (NOS) IDB PID#:
SETTING CLASSIFICATION: Stainless steel rod OPUS PID:
LATITUDE: 37° 36.5' N ( 37.60856) LONGITUDE: 75° 41.2' W ( -75.68642)
The bench mark is a disk located on the east side of Atlantic Avenue near its
intersection with Liberty Street, 21.49 m (70.5 ft) east of the NE corner of a
brick laboratory building, 18.35 m (60.2 ft) north of the NE corner by the front
entrance to the green wood siding house, 7.77 m (25.5 ft) ESE of the centerline
of Atlantic Street, and 0.61 m (2.0 ft) ESE of power pole numbered 29L/317M.
The bench mark is crimped to a stainless steel rod driven 9.8 m (32 ft) to
refusal, and encased in a 6-inch PVC pipe with concrete kickblock.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 9
Station ID: 8631044 PUBLICATION DATE: 04/26/2022
Name: WACHAPREAGUE, WACHAPREAGUE CHANNEL
VA
NOAA Chart: 12210 Latitude: 37° 36.5' N ( 37.60778)
USGS Quad: WACHAPREAGUE Longitude: 75° 41.2' W ( -75.68583)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 1044 J 1997
DESIGNATION: 863 1044 J
MONUMENTATION: Flange-encased Rod VM#: 13783
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Stainless steel rod in sleeve OPUS PID#: AJ4586
LATITUDE: 37° 36.4' N ( 37.60639) LONGITUDE: 75° 41.3' W ( -75.68750)
The bench mark is located on the east side of Atlantic Avenue near its
intersection with Curtis Street, across the street from a small amusement park,
16.79 m (55.1 ft) NNE of the junction of Curtis Street and Atlantic Avenue, 8.02
m (26.3 ft) east of the centerline of Atlantic Avenue, 4.82 m (15.8 ft) SW of
the NW corner of a 0.76 m (2.5 ft) high concrete foundation, and 2.10 m (6.9 ft)
NE of a power pole with light numbered 44119/65535. The datum point is the top
of a stainless steel rod driven 18.3 m (60 ft) to refusal, and encased in a 5
inch NGS logo cap. Note-The sleeve depth does not meet the specifications of a
Class A rod mark.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 9
Station ID: 8631044 PUBLICATION DATE: 04/26/2022
Name: WACHAPREAGUE, WACHAPREAGUE CHANNEL
VA
NOAA Chart: 12210 Latitude: 37° 36.5' N ( 37.60778)
USGS Quad: WACHAPREAGUE Longitude: 75° 41.2' W ( -75.68583)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 1044 K 1998
DESIGNATION: 863 1044 K
MONUMENTATION: Flange-encased Rod VM#: 15479
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Stainless steel rod in sleeve OPUS PID#: AJ4587
LATITUDE: 37° 36.2' N ( 37.60386) LONGITUDE: 75° 41.3' W ( -75.68856)
The bench mark is located near the west corner of the intersection of Main
Street and Atlantic Avenue, 22.35 m (73.3 ft) SW of the SE corner of the
Wachapreague Hotel, 20.73 m (68.0 ft) south of the south corner of the
Wachapreague Hotel office, 13.14 m (43.1 ft) west of power pole numbered 21A
located at the west corner of Atlantic Avenue and Main Street, 10.58 m (34.7 ft)
SSW of the centerline of Main Street, and 0.40 m (1.3 ft) north of a witness
post. The datum point is 0.03 m (0.1 ft) below ground, being the top of a
stainless steel rod driven 19.20 m (63.0 ft), and encased in a five inch NOS
logo cap. Note-The sleeve depth does not meet the specifications of a Class A
rod mark.
BENCH MARK STAMPING: 1044 L 2003
DESIGNATION: 863 1044 L
MONUMENTATION: Tidal Station disk VM#: 17400
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete apron OPUS PID:
LATITUDE: 37° 36.3' N ( 37.60578) LONGITUDE: 75° 41.3' W ( -75.68761)
The bench mark is a disk set in the concrete apron of a one story white block
building on the south side of Atlantic Street located near the intersection of
Atlantic Street and Ice Plant Street, 17.70 m (58.1 ft) SW of a fire hydrant,
14.06 m (46.1 ft) south of a power pole DPL 44116 with three transformers, 8.75
m (28.7 ft) east of the centerline of Atlantic Street, and 0.29 m (1.0 ft) west
of the west side of the building.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 6 of 9
Station ID: 8631044 PUBLICATION DATE: 04/26/2022
Name: WACHAPREAGUE, WACHAPREAGUE CHANNEL
VA
NOAA Chart: 12210 Latitude: 37° 36.5' N ( 37.60778)
USGS Quad: WACHAPREAGUE Longitude: 75° 41.2' W ( -75.68583)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 1044 B RESET 2015
DESIGNATION: 863 1044 B RESET
MONUMENTATION: Tidal Station disk VM#: 21380
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Brick wall OPUS PID:
LATITUDE: 37° 36.5' N ( 37.60833) LONGITUDE: 75° 41.2' W ( -75.68667)
The bench mark is a disk set vertically in the SE corner of a brick laboratory
building near the intersection of Liberty Street and Atlantic Avenue, 11.89 m
(39.0 ft) WNW of the centerline of Atlantic Avenue, 0.43 m (1.4 ft) NNE of the
SE corner of the building, and 1.07 m (3.5 ft) above ground.
BENCH MARK STAMPING: 1044 H RESET 2015
DESIGNATION: 863 1044 H RESET
MONUMENTATION: Tidal Station disk VM#: 21381
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Antenna tower concrete foundation OPUS PID:
LATITUDE: 37° 36.4' N ( 37.60722) LONGITUDE: 75° 41.3' W ( -75.68750)
The bench mark is a disk located south of the Virginia Institute of Marine
Sciences along Atlantic Avenue, in the south side of the concrete foundation of
an antenna tower behind the Harbor Masters Office, 20.39 m (66.9 ft) NNE of the
centerline of the drive to the office parking lot, 8.47 m (27.8 ft) NW of the NW
corner of the office, and 0.85 m (2.8 ft) SW of the center of the tower.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 7 of 9
Station ID: 8631044 PUBLICATION DATE: 04/26/2022
Name: WACHAPREAGUE, WACHAPREAGUE CHANNEL
VA
NOAA Chart: 12210 Latitude: 37° 36.5' N ( 37.60778)
USGS Quad: WACHAPREAGUE Longitude: 75° 41.2' W ( -75.68583)
T I D A L D A T U M S
Tidal datums at WACHAPREAGUE, WACHAPREAGUE CHANNEL based on:
LENGTH OF SERIES: 22 Years
TIME PERIOD: January 1983 - July 2018
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 (02/05/1998) = 2.717
MEAN HIGHER HIGH WATER MHHW = 1.363
MEAN HIGH WATER MHW = 1.265
North American Vertical Datum NAVD88 = 0.794
MEAN SEA LEVEL MSL = 0.688
MEAN TIDE LEVEL MTL = 0.658
MEAN LOW WATER MLW = 0.050
MEAN LOWER LOW WATER MLLW = 0.000
LOWEST OBSERVED WATER LEVEL (03/16/1980) = -0.863
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
1044 G 1981 2.079 0.814
1044 C 1978 2.784 1.519
1044 D 1978 2.394 1.129
1044 E 1978 2.787 1.522
1044 F 1981 2.076 0.811
1044 J 1997 2.056 0.791
1044 K 1998 2.233 0.968
1044 L 2003 2.091 0.826
1044 B RESET 2015 3.422 2.157
1044 H RESET 2015 2.561 1.296
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 8 of 9
Station ID: 8631044 PUBLICATION DATE: 04/26/2022
Name: WACHAPREAGUE, WACHAPREAGUE CHANNEL
VA
NOAA Chart: 12210 Latitude: 37° 36.5' N ( 37.60778)
USGS Quad: WACHAPREAGUE Longitude: 75° 41.2' W ( -75.68583)
Foot Notes:
Bench mark 1044 B RESET 2015 is based on one differential leveling connection
and does not meet the quality control standards of teh NOS. Therefore, caution
should be used when deriving elevations for these marks.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 9 of 9
Station ID: 8631044 PUBLICATION DATE: 04/26/2022
Name: WACHAPREAGUE, WACHAPREAGUE CHANNEL
VA
NOAA Chart: 12210 Latitude: 37° 36.5' N ( 37.60778)
USGS Quad: WACHAPREAGUE Longitude: 75° 41.2' W ( -75.68583)
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.