U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 4
PUBLICATION DATE: 07/10/1990
Station ID: 8630111 SUPERCEDED DATE: 04/21/2003
Name: JESTER'S ISLAND, ASSATEAGUE BAY
VIRGINIA
NOAA Chart: 12211 Latitude: 37° 58.9' N
USGS Quad: CHINCOTEAGUE EAST Longitude: 75° 18.1' W
To reach the tidal bench marks from Greenbackville, proceed by boat ESE across
Chincoteague Bay for about 4.3 statute miles (6.9 km) to the north entrance of
Assateague Bay, continue ESE for about 0.4 statue mile (0.6 km) to the east side
of Assateague Bay and a 1-story frame building (Jester's Clubhouse). The bench
marks are near the clubhouse. The tide gage and staff were on the north end of
a bulkhead.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 0111 A 1985
MONUMENTATION: Survey Disk VM#: 3235
AGENCY: PID:
SETTING CLASSIFICATION: Stainless Steel Rod
The bench mark is 53 feet (16 m) south of the north end of the bulkhead, 15.5
feet (4.7 m) north of the SW corner of Jester's Clubhouse, and 1.0 foot (0.3
m) west of the NW corner of the clubhouse. The bench mark is 0.5 foot (0.2 m)
above ground level, crimped to a stainless steel rod driven 36 feet (11 m) to
refusal.
BENCH MARK STAMPING: 0111 B 1985
MONUMENTATION: Survey Disk VM#: 3236
AGENCY: PID:
SETTING CLASSIFICATION: Stainless Steel Rod
The bench mark is 49.1 feet (15.0 m) SE of the north end of the bulkhead, 40.1
feet (12.2 m) NE of the NW corner of Jester's Clubhouse, and 21.1 feet (6.4 m)
NE of the NE corner of the clubhouse. The bench mark is 0.5 foot (0.2 m) above
ground level, crimped to a stainless steel rod driven 28 feet (9 m).
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 4
PUBLICATION DATE: 07/10/1990
Station ID: 8630111 SUPERCEDED DATE: 04/21/2003
Name: JESTER'S ISLAND, ASSATEAGUE BAY
VIRGINIA
NOAA Chart: 12211 Latitude: 37° 58.9' N
USGS Quad: CHINCOTEAGUE EAST Longitude: 75° 18.1' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 0111 C 1985
MONUMENTATION: Survey Disk VM#: 3237
AGENCY: PID:
SETTING CLASSIFICATION: Stainless Steel Rod
The bench mark is 197 feet (60 m) west of the north end of the bulkhead, 170
feet (52 m) NW of the south end of the bulkhead, and 3.0 feet (0.9 m) north of a
witness post. The bench mark is 0.5 foot (0.2 m) above ground level, crimped to
a stainless steel rod driven 28 feet (9 m).
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 4
PUBLICATION DATE: 07/10/1990
Station ID: 8630111 SUPERCEDED DATE: 04/21/2003
Name: JESTER'S ISLAND, ASSATEAGUE BAY
VIRGINIA
NOAA Chart: 12211 Latitude: 37° 58.9' N
USGS Quad: CHINCOTEAGUE EAST Longitude: 75° 18.1' W
T I D A L D A T U M S
Tidal datums at JESTER'S ISLAND, ASSATEAGUE BAY based on:
LENGTH OF SERIES: 3 MONTHS
TIME PERIOD: AUGUST - OCTOBER 1985
TIDAL EPOCH: 1960-1978
CONTROL TIDE STATION: 8558690 INDIAN RIVER, DE
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in FEET:
HIGHEST OBSERVED WATER LEVEL (09/27/1985) = 4.38
MEAN HIGHER HIGH WATER MHHW = 0.97
MEAN HIGH WATER MHW = 0.88
MEAN TIDE LEVEL MTL = 0.51
MEAN LOW WATER MLW = 0.14
MEAN LOWER LOW WATER MLLW = 0.00
LOWEST OBSERVED WATER LEVEL (08/15/1985) = -0.14
Bench Mark Elevation Information In FEET above:
Stamping or Designation MLLW MHW
0111 A 1985 2.05 1.17
0111 B 1985 1.81 0.93
0111 C 1985 1.92 1.04
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 4
PUBLICATION DATE: 07/10/1990
Station ID: 8630111 SUPERCEDED DATE: 04/21/2003
Name: JESTER'S ISLAND, ASSATEAGUE BAY
VIRGINIA
NOAA Chart: 12211 Latitude: 37° 58.9' N
USGS Quad: CHINCOTEAGUE EAST Longitude: 75° 18.1' 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.