U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 5
PUBLICATION DATE: 05/15/1982
Station ID: 8570282 SUPERCEDED DATE: 04/21/2003
Name: OCEAN CITY, ISLE OF WIGHT BAY
MARYLAND
NOAA Chart: 12211 Latitude: 38° 19.9' N
USGS Quad: OCEAN CITY Longitude: 75° 5.4' W
To reach the tidal bench marks from the intersection of the Route 50 Bridge
(continued) and Philadelphia Avenue proceed south along Philadelphia Avenue to
Talbot Street then east (turn right) along Talbot Street to Isle of Wright Bay.
The tide gage and staff were located at the Talbot Bunting Marina on the pier
closest to the south side of Talbot Street on Isle of Wright Bay.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: NO 4 1929
MONUMENTATION: Survey Disk VM#: 3024
AGENCY: PID#: HU0268
SETTING CLASSIFICATION: Concrete Pavement (Sidewalk)
The bench mark is set near the inner edge of the southeast corner of the
intersection of Somerset Street and Baltimore Avenue. It is slightly elevated
above the level of the sidewalk.
BENCH MARK STAMPING: NO 1 1975
MONUMENTATION: Survey Disk VM#: 3021
AGENCY: PID:
SETTING CLASSIFICATION: Concrete Pavement
The bench mark is set flush in a concrete pavement located at the east end of
Wicomico Street at the junction of the concrete amusement area and a wooden
fishing pier, 63.9 feet (19.5 m) south of the northeast corner of the amusement
area, 33.8 feet (10.3 m) north of the southeast corner of the concrete amusement
area and 0.8 foot (0.2 m) west of the junction of the pier and the amusement
area.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 5
PUBLICATION DATE: 05/15/1982
Station ID: 8570282 SUPERCEDED DATE: 04/21/2003
Name: OCEAN CITY, ISLE OF WIGHT BAY
MARYLAND
NOAA Chart: 12211 Latitude: 38° 19.9' N
USGS Quad: OCEAN CITY Longitude: 75° 5.4' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: NO 2 1975
MONUMENTATION: Survey Disk VM#: 3022
AGENCY: PID:
SETTING CLASSIFICATION: Concrete Pavement (Sidewalk)
The bench mark is set flush in the sidewalk at the south side of Wicomico Street
24.0 feet (7.3 m) south of the centerline of Wicomico Street, 135.0 feet (41.1
m) east of the centerline of Baltimore Avenue, 5.0 feet (1.52 m) east of the
northeast corner of the Laff-In Lounge and Bar, and 0.7 foot (0.2 m) north of
the south edge of the sidewalk.
BENCH MARK STAMPING: NO 3 1975
MONUMENTATION: Survey Disk VM#: 3023
AGENCY: PID#: HU2732
SETTING CLASSIFICATION: Concrete Pavement (Sidewalk)
The bench mark is set flush in the sidewalk at the intersection of St. Louis
Avenue and Dorchester Street, 30.0 feet (9.1 m) east of the centerline of St.
Louis Avenue and 24.0 feet (7.3 m) north of the centerline of Dorchester Street.
BENCH MARK STAMPING: 6 1931
MONUMENTATION: Survey Disk VM#: 3025
AGENCY: PID#: HU0267
SETTING CLASSIFICATION: Concrete Foundation
The bench mark is set horizontally in a ledge of the concrete foundation of the
brick chimney near the northwest corner of a four story frame building located
on the south side of Somerset Street, 117 feet (36 m) east of the east curb of
Baltimore Avenue, 21 feet (6 m) south of the south curb of Somerset Street, 0.75
foot (0.23 m) from the north edge of the foundation and 0.6 foot (0.18 m) above
ground level.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 5
PUBLICATION DATE: 05/15/1982
Station ID: 8570282 SUPERCEDED DATE: 04/21/2003
Name: OCEAN CITY, ISLE OF WIGHT BAY
MARYLAND
NOAA Chart: 12211 Latitude: 38° 19.9' N
USGS Quad: OCEAN CITY Longitude: 75° 5.4' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: E 104 1962
MONUMENTATION: Survey Disk VM#: 3026
AGENCY: PID#: HU0367
SETTING CLASSIFICATION: Concrete Guardrail
The bench mark is set in a vertical drill hole in the southeast end of the
southwest concrete banister of the approach to the U.S. Highway 50 bridge over
the Sinepuxent Bay, 90 feet (27 m) northwest of the centerline of Philadelphia
Avenue and 1 foot (0.3 m) above ground level.
BENCH MARK STAMPING: F 104 1962
MONUMENTATION: Survey Disk VM#: 3027
AGENCY: PID#: HU0366
SETTING CLASSIFICATION: Foundation
The bench mark is set vertically in the northeast brick wall at the north corner
of the Police Department building on the south side of Dorchester Street between
Baltimore Avenue and Philadelphia Avenue, 105 feet (32 m) southeast of the
southeast curb of Philadelphia Avenue, 7.5 feet (2.3 m) southwest of the
southwest curb of Dorchester Street and 2 feet (0.6 m) above the sidewalk.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 5
PUBLICATION DATE: 05/15/1982
Station ID: 8570282 SUPERCEDED DATE: 04/21/2003
Name: OCEAN CITY, ISLE OF WIGHT BAY
MARYLAND
NOAA Chart: 12211 Latitude: 38° 19.9' N
USGS Quad: OCEAN CITY Longitude: 75° 5.4' W
T I D A L D A T U M S
Tidal datums at OCEAN CITY, ISLE OF WIGHT BAY based on:
LENGTH OF SERIES: 17 MONTHS
TIME PERIOD: AUG 1974 - DEC 1976
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 (03/16/1976) = 3.92
MEAN HIGHER HIGH WATER MHHW = 2.62
MEAN HIGH WATER MHW = 2.38
MEAN TIDE LEVEL MTL = 1.26
* NATIONAL GEODETIC VERTICAL DATUM NGVD29 = 1.17
MEAN LOW WATER MLW = 0.14
MEAN LOWER LOW WATER MLLW = 0.00
LOWEST OBSERVED WATER LEVEL (01/11/1977) = -2.51
* NGVD reference based on adjustment of 1977 and NOS levels of 1977.
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In FEET above:
Stamping or Designation MLLW MHW
NO 4 1929 6.38 4.00
NO 1 1975 17.62 15.24
NO 2 1975 7.99 5.61
NO 3 1975 4.26 1.88
6 1931 9.15 6.77
E 104 1962 6.51 4.13
F 104 1962 7.65 5.27
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 5
PUBLICATION DATE: 05/15/1982
Station ID: 8570282 SUPERCEDED DATE: 04/21/2003
Name: OCEAN CITY, ISLE OF WIGHT BAY
MARYLAND
NOAA Chart: 12211 Latitude: 38° 19.9' N
USGS Quad: OCEAN CITY Longitude: 75° 5.4' 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.