U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 5
Station ID: 8740405 PUBLICATION DATE: 07/12/2012
Name: PETIT BOIS ISLAND, MISS. SOUND
MS
NOAA Chart: 11373 Latitude: 30° 12.2' N ( 30.20330)
USGS Quad: PETIT BOIS ISLAND Longitude: 88° 26.5' W ( -88.44170)
To reach the tidal bench marks from the intersection of U.S. Highway 90 and
Market Street in Pascagoula, proceed 2.9 km (1.8 mi) south on Market Street to
Beach Boulevard, then 1.6 km (1.0 mi) west on Beach Boulevard to the public
launching facilities. Proceed by boat out the eastern channel of the harbor and
continue on a 140 magnetic (SE) course for 20 km (11 nm) to Petit Bois Island.
The bench marks are located west of the gage site along the north shore of the
island. The tide gage and staff were located on a three pile structure
approximately 46 m (150 ft) offshore on the north side of the island, and 244 m
(800 ft) east of a tidal creek running orth-south.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 0405 A 1980
DESIGNATION: 874 0405 A 1980
MONUMENTATION: Survey disk VM#: 11400
AGENCY: National Ocean Survey (NOS) IDB PID#:
SETTING CLASSIFICATION: OPUS PID:
LATITUDE: 30° 12.2' N ( 30.20330) LONGITUDE: 88° 26.0' W ( -88.43333)
The primary bench mark is a disk nearly directly inshore from the tide gage
platform, 84 m (277 ft) west of a 1.83 m (6.0 ft) D.B.H. bayberry bush, 30 m
(100 ft) south of the north shoreline of the island, and 18 m (60 ft) north of
the NE end of a pond. The bench mark is set 0.06 m (0.2 ft) below ground level,
crimped to a steel rod driven 17 m (55 ft) to refusal and encased in a 4-inch
PVC pipe and concrete kickblock.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 5
Station ID: 8740405 PUBLICATION DATE: 07/12/2012
Name: PETIT BOIS ISLAND, MISS. SOUND
MS
NOAA Chart: 11373 Latitude: 30° 12.2' N ( 30.20330)
USGS Quad: PETIT BOIS ISLAND Longitude: 88° 26.5' W ( -88.44170)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 0405 B 1980
DESIGNATION: 874 0405 B 1980
MONUMENTATION: Survey disk VM#: 11401
AGENCY: National Ocean Survey (NOS) IDB PID#:
SETTING CLASSIFICATION: OPUS PID:
LATITUDE: 30° 12.2' N ( 30.20330) LONGITUDE: 88° 26.0' W ( -88.43333)
The bench mark is a disk 66 m (215 ft) WSW of bench mark 0405 A 1980, 34 m (112
ft) SSE of the north shoreline of the island in line with a refinery on the
mainland, and 15 m (48 ft) north of a pond. The bench mark is set 0.06 m (0.2
ft) below ground level, crimped to a steel rod driven 17 m (55 ft) to refusal
and encased in a 4-inch PVC pipe and concrete kickblock.
BENCH MARK STAMPING: 0405 C 1980
DESIGNATION: 874 0405 C 1980
MONUMENTATION: Survey disk VM#: 11402
AGENCY: National Ocean Survey (NOS) IDB PID#:
SETTING CLASSIFICATION: OPUS PID:
LATITUDE: 30° 12.2' N ( 30.20330) LONGITUDE: 88° 26.0' W ( -88.43333)
The bench mark is a disk 63 m (208 ft) WSW of bench mark 0405 B 1980, 35 m (114
ft) south of the north shoreline of the island, 26 m (85 ft) north of a pond,
and 17 m (56 ft) NE of a lone fence post. The bench mark is set 0.06 m (0.2 ft)
below ground level, crimped to a steel rod driven 17 m (55 ft) to refusal and
encased in a 4-inch PVC pipe and concrete kickblock.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 5
Station ID: 8740405 PUBLICATION DATE: 07/12/2012
Name: PETIT BOIS ISLAND, MISS. SOUND
MS
NOAA Chart: 11373 Latitude: 30° 12.2' N ( 30.20330)
USGS Quad: PETIT BOIS ISLAND Longitude: 88° 26.5' W ( -88.44170)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 0405 D 1980
DESIGNATION: 874 0405 D 1980
MONUMENTATION: Survey disk VM#: 11403
AGENCY: National Ocean Survey (NOS) IDB PID#:
SETTING CLASSIFICATION: OPUS PID:
LATITUDE: 30° 12.2' N ( 30.20330) LONGITUDE: 88° 26.0' W ( -88.43333)
The bench mark is a disk 67 m (220 ft) WSW of bench mark 0405 C 1980, 23 m (77
ft) NE of bayberry bushes, and 18 m (58 ft) SE of the north shoreline of Petit
Bois Island in line with Round Island. The bench mark is set 0.06 m (0.2 ft)
below ground level, crimped to a steel rod driven 17 m (55 ft) to refusal and
encased in a 4-inch PVC pipe and concrete kickblock.
BENCH MARK STAMPING: GARY 1958
DESIGNATION: 874 0405 GARY 1958
MONUMENTATION: Survey disk VM#: 11404
AGENCY: IDB PID#:
SETTING CLASSIFICATION: Set in pipe with concrete base OPUS PID:
LATITUDE: 30° 12.2' N ( 30.20330) LONGITUDE: 88° 26.0' W ( -88.43333)
The bench mark is a disk set in top of a pipe with a concrete base, 96 m (316
ft) WSW of bench mark 0405 D 1980, 37 m (120 ft) west of the center of a 3 m (10
ft) wide tidal creek running north-south, and 18 m (59 ft) south of the north
shoreline of the island in line with the refinery at Pascagoula.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 5
Station ID: 8740405 PUBLICATION DATE: 07/12/2012
Name: PETIT BOIS ISLAND, MISS. SOUND
MS
NOAA Chart: 11373 Latitude: 30° 12.2' N ( 30.20330)
USGS Quad: PETIT BOIS ISLAND Longitude: 88° 26.5' W ( -88.44170)
T I D A L D A T U M S
Tidal datums at PETIT BOIS ISLAND, MISS. SOUND based on:
LENGTH OF SERIES: 7 MONTHS
TIME PERIOD: April 1980 - October 1980
TIDAL EPOCH: 1983-2001
CONTROL TIDE STATION: 8735180 DAUPHIN ISLAND, MOBILE BAY
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
MEAN HIGHER HIGH WATER MHHW = 0.447
MEAN HIGH WATER MHW = 0.430
MEAN TIDE LEVEL MTL = 0.222
MEAN SEA LEVEL MSL = 0.216
MEAN LOW WATER MLW = 0.015
MEAN LOWER LOW WATER MLLW = 0.000
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
0405 A 1980 0.886 0.456
0405 B 1980 0.764 0.334
0405 C 1980 0.854 0.424
0405 D 1980 0.477 0.047
GARY 1958 1.976 1.546
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 5
Station ID: 8740405 PUBLICATION DATE: 07/12/2012
Name: PETIT BOIS ISLAND, MISS. SOUND
MS
NOAA Chart: 11373 Latitude: 30° 12.2' N ( 30.20330)
USGS Quad: PETIT BOIS ISLAND Longitude: 88° 26.5' W ( -88.44170)
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.