U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 4
PUBLICATION DATE: 08/17/1988
Station ID: 8632366 SUPERCEDED DATE: 04/21/2003
Name: CAPE CHARLES, CHESAPEAKE BAY
VIRGINIA
NOAA Chart: 12224 Latitude: 37° 15.8' N
USGS Quad: CAPE CHARLES Longitude: 76° 0.9' W
To reach the tidal bench marks from the intersection of U.S. Route 13 Bypass and
State Route 184, proceed west on State Route 184 0.4 mile (0.6 km) to Cape
Junction at the intersection of State Routes 184 and 641, then proceed south on
State Route 641 for 0.2 mile (0.3 km) to its intersection with State Route 642,
then proceed west on State Route 642 1.5 miles (2.4 km) to its end, then proceed
north to the first intersection, and then west to the U.S. Coast Guard Station
at the Harbor of Refuge. The bench marks are located around the Coast Guard
Station. The tide gage and staff were at the end of the U.S. Coast Guard
Station Pier.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: Z 313 1952
MONUMENTATION: Survey Disk VM#: 3366
AGENCY: PID#: GV0340
SETTING CLASSIFICATION: Concrete Foundation
The bench mark is set in a concrete foundation at the abandoned telephone office
in the town of Cape Charles, 0.3 mile (0.5 km) south of the bridge over the
railroad tracks where the road turns left (SR642) in a former foundation of a
tower, 6.0 feet (1.8 m) from the northeasternmost corner of the abandoned
building, and 0.5 foot (0.2 m) from a fiberglass witness post.
BENCH MARK STAMPING: NO 5 RESET 1981
MONUMENTATION: Survey Disk VM#: 3367
AGENCY: PID#: GV3550
SETTING CLASSIFICATION: Concrete Wall
The bench mark is set in a concrete wall forming the aeration tank at the sewage
treatment plant in the town of Cape Charles, 240 feet (73 m) south of State Road
1108, and 1.0 foot (0.3 m) west of two 6-inch cast iron pipes that deliver
sludge to the bed.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 4
PUBLICATION DATE: 08/17/1988
Station ID: 8632366 SUPERCEDED DATE: 04/21/2003
Name: CAPE CHARLES, CHESAPEAKE BAY
VIRGINIA
NOAA Chart: 12224 Latitude: 37° 15.8' N
USGS Quad: CAPE CHARLES Longitude: 76° 0.9' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 2366 A 1982
MONUMENTATION: Survey Disk VM#: 3368
AGENCY: PID:
SETTING CLASSIFICATION: Concrete Foundation
The bench mark is set in the concrete foundation presently used as the base to a
weather instrument tower, 87.5 feet (26.7 m) bearing 248o (mag) from the
triangular radio tower, 77.5 feet (23.6 m) west from the SW corner of the Preta
B A70N Building on the Coast Guard property, and 11.8 feet (3.6 m) east of a
metal sheet pile.
BENCH MARK STAMPING: 2366 B 1982
MONUMENTATION: Survey Disk VM#: 3369
AGENCY: PID:
SETTING CLASSIFICATION: Concrete Walkway
The bench mark is set in a concrete walkway forming the cap of a concrete sea
wall, at the NE corner where it makes an inside corner in the immediate vicinity
of a large cleat, 147 feet (45 m) bearing 154o (mag) from telephone pole 34437
DP&L 53205 DP&L 785, and 110 feet (34 m) NW of the NW corner of the westernmost
of two boat ramps west of the Coast Guard Station.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 4
PUBLICATION DATE: 08/17/1988
Station ID: 8632366 SUPERCEDED DATE: 04/21/2003
Name: CAPE CHARLES, CHESAPEAKE BAY
VIRGINIA
NOAA Chart: 12224 Latitude: 37° 15.8' N
USGS Quad: CAPE CHARLES Longitude: 76° 0.9' W
T I D A L D A T U M S
Tidal datums at CAPE CHARLES, CHESAPEAKE BAY based on:
LENGTH OF SERIES: 3 MONTHS
TIME PERIOD: APRIL - JUNE 1982
TIDAL EPOCH: 1960-1978
CONTROL TIDE STATION: 8638610 HAMPTON ROADS
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in FEET:
HIGHEST OBSERVED WATER LEVEL (06/19/1982) = 3.80
MEAN HIGHER HIGH WATER MHHW = 2.66
MEAN HIGH WATER MHW = 2.44
MEAN TIDE LEVEL MTL = 1.28
MEAN LOW WATER MLW = 0.11
MEAN LOWER LOW WATER MLLW = 0.00
LOWEST OBSERVED WATER LEVEL (03/28/1982) = -1.25
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In FEET above:
Stamping or Designation MLLW MHW
Z 313 1952 13.39 10.95
NO 5 RESET 1981 13.28 10.84
2366 A 1982 7.57 5.13
2366 B 1982 7.09 4.65
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 4
PUBLICATION DATE: 08/17/1988
Station ID: 8632366 SUPERCEDED DATE: 04/21/2003
Name: CAPE CHARLES, CHESAPEAKE BAY
VIRGINIA
NOAA Chart: 12224 Latitude: 37° 15.8' N
USGS Quad: CAPE CHARLES Longitude: 76° 0.9' W
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 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.