U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 5
Station ID: 8744756 PUBLICATION DATE: 06/13/2003
Name: SHIP ISLAND, MISSISSIPPI SOUND
MISSISSIPPI
NOAA Chart: 11372 Latitude: 30° 12.8' N
USGS Quad: SHIP ISLAND Longitude: 88° 58.3' W
To reach the tidal bench marks from the Gulfport Small Craft Harbor, proceed by
boat on a heading of 145 magnetic degrees for 19.1 km (10.3 nm) to the west end
of Ship Island where the National Park Service (NPS) maintains a pier. The
bench marks are along the north-south walkway and east of the concession stand.
The tide gage and staff were at the north end of the pier.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 4756 A 1979
DESIGNATION: 874 4756 A
MONUMENTATION: Tidal Station disk VM#: 10369
AGENCY: National Ocean Survey (NOS) PID:
SETTING CLASSIFICATION: Stainless steel rod
The primary bench mark is a disk located near the concession stand SE of Fort
Massachusetts, 46 m (152 ft) south of the entrance to Fort Massachusetts, 21.18
m (69.5 ft) SE of the SE corner of Fort Massachusetts, 6.86 m (22.5 ft) NW of
the NW corner of the concession building, and 0.3 m (1 ft) NE of the inside
corner of the intersection of the main north-south wooden walkway and the
walkway to the concession stand. The bench mark is set 9 cm (0.3 ft) below
ground level, crimped to the top of a stainless steel rod driven 16.8 m (55 ft)
to refusal, and encased in a PVC pipe and concrete kickblock.
BENCH MARK STAMPING: SIGNAL 1966
DESIGNATION: SIGNAL AZ MK
MONUMENTATION: Azimuth Mark disk VM#: 10368
AGENCY: US Coast and Geodetic Survey (USC&GS) PID#: BH1905
SETTING CLASSIFICATION: Stainless steel rod
The bench mark is a disk located about 299 m (981 ft) south of the entrance to
Fort Massachusetts, 213 m (700 ft) north of the approximate waters edge on the
south side of Ship Island as measured along the wooden walkway, 152 m (500 ft)
north of the crest of the dune line on the south side of the island, and 12 m
(41 ft) west of the centerline of the wooden walkway. The bench mark is set 1 m
(2 ft) above grade, crimped to the top of a copper-clad steel rod driven to an
unspecified depth, and encased in an asbestos pipe.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 5
Station ID: 8744756 PUBLICATION DATE: 06/13/2003
Name: SHIP ISLAND, MISSISSIPPI SOUND
MISSISSIPPI
NOAA Chart: 11372 Latitude: 30° 12.8' N
USGS Quad: SHIP ISLAND Longitude: 88° 58.3' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 4756 B 1979
DESIGNATION: 874 4756 B
MONUMENTATION: Tidal Station disk VM#: 10370
AGENCY: National Ocean Survey (NOS) PID:
SETTING CLASSIFICATION: Stainless steel rod
The bench mark is a disk located east of the NW corner of the concession stand,
93 m (306 ft) SE of the entrance to old Fort Massachusetts, 65.38 m (214.5 ft)
east along a wind fence line from bench mark 4756 A 1979, and 59 m (192 ft) east
of the NW corner of the NPS concession building at the northern toe of the dune
line on the Mississippi Sound side of the island, next to a witness sign. The
bench mark is set 9 cm (0.3 ft) below ground level, crimped to the top of a
stainless steel rod driven 15.2 m (50 ft) to refusal, and encased in a PVC pipe
and concrete kickblock.
BENCH MARK STAMPING: 4756 C 1979
DESIGNATION: 874 4756 C
MONUMENTATION: Tidal Station disk VM#: 10371
AGENCY: National Ocean Survey (NOS) PID:
SETTING CLASSIFICATION: Stainless steel rod
The bench mark is a disk located on the crest of the dune line along the
Mississippi Sound side of the island, 157 m (516 ft) SE of the entrance to Fort
Massachusetts, 64 m (210 ft) east of bench mark 4756 B 1979, 28 m (92 ft) NW of
a NPS weather station, and next to a witness post. The bench mark is set 12 cm
(0.4 ft) below ground level, crimped to the top of a stainless steel rod driven
16.8 m (55 ft) to refusal, and encased in a PVC pipe and concrete kickblock.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 5
Station ID: 8744756 PUBLICATION DATE: 06/13/2003
Name: SHIP ISLAND, MISSISSIPPI SOUND
MISSISSIPPI
NOAA Chart: 11372 Latitude: 30° 12.8' N
USGS Quad: SHIP ISLAND Longitude: 88° 58.3' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 4756 D 1979
DESIGNATION: 874 4756 D
MONUMENTATION: Tidal Station disk VM#: 10372
AGENCY: National Ocean Survey (NOS) PID:
SETTING CLASSIFICATION: Stainless steel rod
The bench mark is a disk located 149 m (490 ft) south along a wooden walkway
across the island from the entrance to Fort Massachusetts, 103 m (338 ft) south
of bench mark 4756 A 1979, 7 m (24 ft) west of the centerline of the wooden
walkway on the crest of a sand dune line running along the axis of the center of
the island, and next to a witness post. The bench mark is set 12 cm (0.4 ft)
below grade, crimped to the top of a stainless steel rod driven 16.8 m (55 ft)
to refusal, and encased in a PVC pipe and concrete kickblock.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 5
Station ID: 8744756 PUBLICATION DATE: 06/13/2003
Name: SHIP ISLAND, MISSISSIPPI SOUND
MISSISSIPPI
NOAA Chart: 11372 Latitude: 30° 12.8' N
USGS Quad: SHIP ISLAND Longitude: 88° 58.3' W
T I D A L D A T U M S
Tidal datums at SHIP ISLAND, MISSISSIPPI SOUND based on:
LENGTH OF SERIES: 4 MONTHS
TIME PERIOD: July 1980 - October 1980
TIDAL EPOCH: 1983-2001
CONTROL TIDE STATION: 8743735 BILOXI (CADET POINT), BILOXI BAY
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
MEAN HIGHER HIGH WATER (MHHW) = 0.513
MEAN HIGH WATER (MHW) = 0.476
MEAN SEA LEVEL (MSL) = 0.257
MEAN TIDE LEVEL (MTL) = 0.256
MEAN LOW WATER (MLW) = 0.035
MEAN LOWER LOW WATER (MLLW) = 0.000
National Geodetic Vertical Datum (NGVD 29)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
4756 A 1979 1.328 0.852
SIGNAL 1966 1.690 1.214
4756 B 1979 1.271 0.795
4756 C 1979 1.705 1.229
4756 D 1979 1.307 0.831
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 5
Station ID: 8744756 PUBLICATION DATE: 06/13/2003
Name: SHIP ISLAND, MISSISSIPPI SOUND
MISSISSIPPI
NOAA Chart: 11372 Latitude: 30° 12.8' N
USGS Quad: SHIP ISLAND Longitude: 88° 58.3' 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 (NAVD 88).
NGVD 29 is a fixed datum adopted as a national standard geodetic reference for
heights but is now considered superseded. NGVD 29 is sometimes referred to as
Sea Level Datum of 1929 or as Mean Sea Level on some early issues of Geological
Survey Topographic Quads. NGVD 29 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 NGVD 29 are available from the National
Geodetic Survey (NGS) data base via the World Wide Web at
National Geodetic Survey.
NAVD 88 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. NAVD 88 replaces NGVD 29 as the national
standard geodetic reference for heights. Bench mark elevations relative to
NAVD 88 are available from NGS through the World Wide Web at
National Geodetic Survey.
NGVD 29 and NAVD 88 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 NAVD 88 elevation is shown on the Elevations of Tidal Datums Table Referred
to MLLW only when two or more of the bench marks listed have NAVD 88 elevations.
The NAVD 88 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, NAVD 88 bench mark elevations computed indirectly from the tidal
datums elevation table may differ slightly from NAVD 88 elevations listed for
each bench mark in the NGS database.