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National Ocean Service
Datums Page Page 1 of 7
Station ID: 8637689 PUBLICATION DATE: 12/15/2020
Name: YORKTOWN USCG TRAINING CENTER, YORK R.
VA
NOAA Chart: 12241 Latitude: 37° 13.6' N ( 37.22650)
USGS Quad: POQUOSON WEST Longitude: 76° 28.7' W ( -76.47881)
To reach the tide station from the intersection of Route 17 North (George
Washington Memorial Highway) and Cook Road (State Route 704), proceed in a
northerly direction for 3.7 km (2.3 mi) to the intersection of Cook Road and
Route 238. Turn east (right) and continue on Route 238 for approximately 2.2
km (1.4 mi) to the main gate at the US Coast Guard Training Center Yorktown.
Pass through the gate, proceed for about 0.19 km (0.1 mi) and turn north (left)
onto Pier Road. Proceed on Pier Road to the bottom of the hill and the entrance
to the Coast Guard pier. The tide gauge is located at berth 5 on the north
(offshore) end of the pier. The bench marks are located on and in the vicinity
of the Coast Guard property.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 7689 C 2008
DESIGNATION: 863 7689 C
MONUMENTATION: Metal Rod VM#: 19122
AGENCY: National Ocean Service (NOS) IDB PID:
SETTING CLASSIFICATION: OPUS PID#: BBDK92
LATITUDE: 37° 13.3' N ( 37.22094) LONGITUDE: 76° 29.0' W ( -76.48272)
The primary benchmark is a stainless steel rod located on the high point of a
hill in the vicinity of the executive officers house between parking lots 2 and
9, 28.70 m (94.16 ft) southwest and up the hill from the west edge of parking
lot 9, 21.44 m (70.34 ft) NNE of parking lot 2 NW corner on the east side of the
drive way leading to CDR Brown family residence house, 16.65 m (54.62 ft) WNW
and up the hill from the NW corner of a 2.9 m (9.5 ft) x 4.8 m (15.7 ft)
concrete pad holding power transformers, and 0.35 m (1.1 ft) E of a witness
post.The datum point is the high point of a stainless steel rod driven 24.2m
(79.5 ft) to refusal and encased in a concrete kick block
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 7
Station ID: 8637689 PUBLICATION DATE: 12/15/2020
Name: YORKTOWN USCG TRAINING CENTER, YORK R.
VA
NOAA Chart: 12241 Latitude: 37° 13.6' N ( 37.22650)
USGS Quad: POQUOSON WEST Longitude: 76° 28.7' W ( -76.47881)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: STATION NO. 052
DESIGNATION: 052
MONUMENTATION: Survey disk VM#: 17486
AGENCY: York County IDB PID#: GV5961
SETTING CLASSIFICATION: Concrete monument OPUS PID#: GV5961
LATITUDE: 37° 13.3' N ( 37.22170) LONGITUDE: 76° 29.2' W ( -76.48670)
The bench mark is a disk set in a concrete monument, 7.92 m (26.0 ft) north of
the centerline of Route 676, 7.47 m (24.5 ft) west of the centerline of Hamilton
Avenue, 2.13 m (7.0 ft) SW of the street sign, and 0.05 m (0.2 ft) below the
ground level.
BENCH MARK STAMPING: 7689 B 2004
DESIGNATION: 863 7689 B
MONUMENTATION: Tidal Station disk VM#: 17487
AGENCY: National Ocean Service (NOS) IDB PID:
SETTING CLASSIFICATION: Concrete bulkhead OPUS PID#: BBFH02
LATITUDE: 37° 13.3' N ( 37.22164) LONGITUDE: 76° 29.0' W ( -76.48253)
The bench mark is a disk set in the top of a concrete bulkhead located at the
west side of the concrete pier at the US Coast Guard Training Center Yorktown,
49.21 m (161.4 ft) west of the centerline of the Coast Guard pier, 32.44 m
(106.4 ft) north of the NW corner of a small cinderblock building NO. 178, 3.21
m (10.5 ft) east of the west end of the bulkhead, and 0.35 m (1.15 ft) south of
the north face of the bulkhead.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 7
Station ID: 8637689 PUBLICATION DATE: 12/15/2020
Name: YORKTOWN USCG TRAINING CENTER, YORK R.
VA
NOAA Chart: 12241 Latitude: 37° 13.6' N ( 37.22650)
USGS Quad: POQUOSON WEST Longitude: 76° 28.7' W ( -76.47881)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 7689 A 2004
DESIGNATION: 863 7689 A
MONUMENTATION: Tidal Station disk VM#: 17488
AGENCY: National Ocean Service (NOS) IDB PID:
SETTING CLASSIFICATION: Concrete pier OPUS PID:
LATITUDE: 37° 13.5' N ( 37.22478) LONGITUDE: 76° 28.8' W ( -76.47964)
The bench mark is a disk set flush in the deck of the concrete pier at the US
Coast Guard Training Center Yorktown located near the NW corner of the base,
7.01 m (23.0 ft) SW of the NW corner of a small wood frame structure believed to
be a pump house on the east side of the pier, 6.45 m (21.2 ft) of the NW of the
SW corner of the same wood frame structure, and 0.43 m (1.4 ft) east of the west
face of the pier.
BENCH MARK STAMPING: EL. 12.679 FT.
DESIGNATION: 863 7689 EL. 12.679
MONUMENTATION: Survey disk VM#: 17489
AGENCY: US Coast Guard (USCG) IDB PID:
SETTING CLASSIFICATION: Concrete pier OPUS PID#: BBBM58
LATITUDE: 37° 13.6' N ( 37.22644) LONGITUDE: 76° 28.7' W ( -76.47875)
The bench mark is a disk set flush in the deck of the concrete pier at the US
Coast Guard Training Center Yorktown located near the NW corner of the base,
26.40 m (86.6 ft) NW of the SE corner of the pier, 17.75 m (58.2 ft) SE of the
SW corner of the pier, and 0.43 m (1.4 ft) north of the south face of the pier.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 7
Station ID: 8637689 PUBLICATION DATE: 12/15/2020
Name: YORKTOWN USCG TRAINING CENTER, YORK R.
VA
NOAA Chart: 12241 Latitude: 37° 13.6' N ( 37.22650)
USGS Quad: POQUOSON WEST Longitude: 76° 28.7' W ( -76.47881)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: FUEL 1988
DESIGNATION: FUEL
MONUMENTATION: Tidal Station disk VM#: 17490
AGENCY: National Ocean Service (NOS) IDB PID#: AE4247
SETTING CLASSIFICATION: Concrete pier OPUS PID:
LATITUDE: 37° 13.6' N ( 37.22625) LONGITUDE: 76° 28.6' W ( -76.47642)
The bench mark is a disk cemented into a drill hole in the concrete pier, 31.49
m (103.3 ft) west from the extreme NE corner of the pier, 11.25 m (36.9 ft)
north of the south face of the pier, and 1.04 m (3.4 ft) south from the north
edge of the concrete pier.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 7
Station ID: 8637689 PUBLICATION DATE: 12/15/2020
Name: YORKTOWN USCG TRAINING CENTER, YORK R.
VA
NOAA Chart: 12241 Latitude: 37° 13.6' N ( 37.22650)
USGS Quad: POQUOSON WEST Longitude: 76° 28.7' W ( -76.47881)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: STATION NO. 051
DESIGNATION: 051
MONUMENTATION: Survey disk VM#: 17588
AGENCY: York County IDB PID#: GV5960
SETTING CLASSIFICATION: Concrete monument OPUS PID:
LATITUDE: 37° 13.6' N ( 37.22670) LONGITUDE: 76° 29.8' W ( -76.49670)
The bench mark is a disk set in concrete, 5.49 m (18.0 ft) NE of the edge of the
pavement of Route 238, 3.51 m (11.5 ft) west of the stop sign, and 0.08 m (0.26
ft) below the ground level.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 6 of 7
Station ID: 8637689 PUBLICATION DATE: 12/15/2020
Name: YORKTOWN USCG TRAINING CENTER, YORK R.
VA
NOAA Chart: 12241 Latitude: 37° 13.6' N ( 37.22650)
USGS Quad: POQUOSON WEST Longitude: 76° 28.7' W ( -76.47881)
T I D A L D A T U M S
Tidal datums at YORKTOWN USCG TRAINING CENTER, YORK R. based on:
LENGTH OF SERIES: 15 YEARS
TIME PERIOD: November 2004 - October 2019
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 (11/12/2009) = 2.091
MEAN HIGHER HIGH WATER MHHW = 0.786
MEAN HIGH WATER MHW = 0.727
North American Vertical Datum NAVD88 = 0.468
MEAN TIDE LEVEL MTL = 0.382
MEAN SEA LEVEL MSL = 0.378
MEAN LOW WATER MLW = 0.036
MEAN LOWER LOW WATER MLLW = 0.000
LOWEST OBSERVED WATER LEVEL (02/17/2007) = -0.578
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
7689 C 2008 8.717 7.990
STATION NO. 052 13.422 12.695
7689 B 2004 3.484 2.757
7689 A 2004 4.022 3.295
EL. 12.679 FT. 3.999 3.272
FUEL 1988 4.027 3.300
STATION NO. 051 17.063 16.336
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 7 of 7
Station ID: 8637689 PUBLICATION DATE: 12/15/2020
Name: YORKTOWN USCG TRAINING CENTER, YORK R.
VA
NOAA Chart: 12241 Latitude: 37° 13.6' N ( 37.22650)
USGS Quad: POQUOSON WEST Longitude: 76° 28.7' W ( -76.47881)
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.