U.S. DEPARTMENT OF COMMERCE
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National Ocean Service
Datums Page Page 1 of 6
Station ID: 8745799 PUBLICATION DATE: 02/26/2004
Name: CAT ISLAND, MISSISSIPPI SOUND
MS
NOAA Chart: 11372 Latitude: 30° 13.9' N ( 30.23170)
USGS Quad: CAT ISLAND Longitude: 89° 7.0' W ( -89.11670)
To reach the tidal bench marks from Long Beach Harbor, proceed by boat on a
heading of 165 magnetic (approx. SSE) for 13.3 km (9.5 nm), then west along the
north shoreline of Cat Island to the gage site. The bench marks are located
south of the gage site along a two-rut dirt road. The tide gage and staff were
located on the northernmost of a series of abandoned pier pilings in a small
cove.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 5799 A 1979
DESIGNATION: 874 5799 A TIDAL
MONUMENTATION: Tidal Station disk VM#: 10386
AGENCY: National Ocean Survey (NOS) IDB PID#:
SETTING CLASSIFICATION: Stainless steel rod OPUS PID#: BBBG93
LATITUDE: 30° 13.9' N ( 30.23170) LONGITUDE: 89° 7.0' W ( -89.11670)
The primary bench mark is a disk located 84 m (277 ft) west along a two-rut dirt
road from the centerline of the abandoned pier, 61 m (200 ft) west along the
dirt road from bench mark ARMY 1951 NO 2 1966, 41 m (136 ft) south of the north
shoreline, 16 m (53 ft) NE of a 0.37 m (1.2 ft) diameter pine tree with a 35
bend in its trunk, and 12 m (41 ft) south of the centerline of the dirt road.
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 substantial resistance, and encased
in a PVC pipe and concrete kickblock.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 6
Station ID: 8745799 PUBLICATION DATE: 02/26/2004
Name: CAT ISLAND, MISSISSIPPI SOUND
MS
NOAA Chart: 11372 Latitude: 30° 13.9' N ( 30.23170)
USGS Quad: CAT ISLAND Longitude: 89° 7.0' W ( -89.11670)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: ARMY 1951
DESIGNATION: ARMY
MONUMENTATION: Topographic Station disk VM#: 10383
AGENCY: US Coast & Geodetic Survey
(USC&GS) IDB PID#: BH2616
SETTING CLASSIFICATION: Concrete monument OPUS PID:
LATITUDE: 30° 13.8' N ( 30.23000) LONGITUDE: 89° 7.0' W ( -89.11670)
The bench mark is a disk set in a concrete monument, 23 m (77 ft) south of the
north shoreline, 13 m (43 ft) NW of bench mark ARMY 1952 NO 1 1966, 6 m (19 ft)
south of the centerline of the dirt road, 1 m (4 ft) NW of a metal witness post
and 1 m (2 ft) west of the centerline of the abandoned pier.
BENCH MARK STAMPING: ARMY 1952 NO 1 1966
DESIGNATION: 874 5799 ARMY 1
MONUMENTATION: Reference Mark disk VM#: 10384
AGENCY: US Coast & Geodetic Survey
(USC&GS) IDB PID#: AE4778
SETTING CLASSIFICATION: Copper weld ground rod OPUS PID:
LATITUDE: 30° 13.9' N ( 30.23170) LONGITUDE: 89° 7.0' W ( -89.11670)
The bench mark is a disk located 34 m (111 ft) south of the north shoreline, 17
m (57 ft) south of the centerline of the dirt road, and 4 m (13 ft) east of the
centerline of the abandoned pier. The bench mark is crimped to the top of a
copper weld ground rod driven 4.9 m (16 ft) and encased in a 4 inch orageburg
pipe.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 6
Station ID: 8745799 PUBLICATION DATE: 02/26/2004
Name: CAT ISLAND, MISSISSIPPI SOUND
MS
NOAA Chart: 11372 Latitude: 30° 13.9' N ( 30.23170)
USGS Quad: CAT ISLAND Longitude: 89° 7.0' W ( -89.11670)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: ARMY 1952 NO 2 1966
DESIGNATION: ARMY 1966 RM 2
MONUMENTATION: Reference Mark disk VM#: 10385
AGENCY: US Coast & Geodetic Survey
(USC&GS) IDB PID#: BH2615
SETTING CLASSIFICATION: Copper weld ground rod OPUS PID:
LATITUDE: 30° 13.8' N ( 30.23000) LONGITUDE: 89° 7.0' W ( -89.11670)
The bench mark is a disk located 26 m (84 ft) west of bench mark ARMY 1951, 23 m
(77 ft) west along the dirt road from the centerline of the abandoned pier, 20 m
(67 ft) south of the north shoreline, and 3 m (9 ft) south of the centerline of
the dirt road. The bench mark is crimped to the top of a copper weld ground rod
driven 4.9 m (16 ft) and encased in a 4 inch orageburg pipe.
BENCH MARK STAMPING: 5799 B 1979
DESIGNATION: 874 5799 B TIDAL
MONUMENTATION: Tidal Station disk VM#: 10387
AGENCY: National Ocean Survey (NOS) IDB PID#:
SETTING CLASSIFICATION: Stainless steel rod OPUS PID:
LATITUDE: 30° 13.9' N ( 30.23170) LONGITUDE: 89° 7.0' W ( -89.11670)
The bench mark is a disk located 66 m (218 ft) west along the dirt road from
bench mark 5799 A 1979, 49 m (160 ft) south of the north shoreline, 26 m (86 ft)
south of the south shoreline of a tidal slough, 7 m (23 ft) south of a 0.3 m (1
ft) diameter oak tree, and 3 m (9 ft) north of the centerline of the dirt road.
The bench mark is set 6 cm (0.2 ft) below ground level, crimped to the top of a
stainless steel rod driven 15.2 m (50 ft) to substantial resistance, 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 4 of 6
Station ID: 8745799 PUBLICATION DATE: 02/26/2004
Name: CAT ISLAND, MISSISSIPPI SOUND
MS
NOAA Chart: 11372 Latitude: 30° 13.9' N ( 30.23170)
USGS Quad: CAT ISLAND Longitude: 89° 7.0' W ( -89.11670)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 5799 C 1979
DESIGNATION: 874 5799 C TIDAL
MONUMENTATION: Tidal Station disk VM#: 10388
AGENCY: National Ocean Survey (NOS) IDB PID#:
SETTING CLASSIFICATION: Stainless steel rod OPUS PID:
LATITUDE: 30° 13.9' N ( 30.23170) LONGITUDE: 89° 7.0' W ( -89.11670)
The bench mark is a disk located 73 m (241 ft) west along a the dirt road from
bench mark 5799 B 1979, 67 m (221 ft) south of the north shoreline, 37 m (121
ft) SE of a 2 m (5 ft) diameter oak tree, 26 m (86 ft) east of the east end of a
concrete cow trough, 16 m (53 ft) south of the centerline of the dirt road, and
4 m (14 ft) north of an 0.46 m (1.5 ft) diameter tree. The bench mark is set 9
cm (0.3 ft) below ground level, crimped to the top of a stainless steel rod
driven 13.7 m (45 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 5 of 6
Station ID: 8745799 PUBLICATION DATE: 02/26/2004
Name: CAT ISLAND, MISSISSIPPI SOUND
MS
NOAA Chart: 11372 Latitude: 30° 13.9' N ( 30.23170)
USGS Quad: CAT ISLAND Longitude: 89° 7.0' W ( -89.11670)
T I D A L D A T U M S
Tidal datums at CAT ISLAND, MISSISSIPPI SOUND based on:
LENGTH OF SERIES: 2 MONTHS
TIME PERIOD: December 1979 - January 1980
TIDAL EPOCH: 1983-2001
CONTROL TIDE STATION: 8747437 BAY WAVELAND YC, BAY ST. LOUIS
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
MEAN HIGHER HIGH WATER MHHW = 0.479
MEAN HIGH WATER MHW = 0.450
MEAN TIDE LEVEL MTL = 0.239
MEAN SEA LEVEL MSL = 0.236
MEAN LOW WATER MLW = 0.028
MEAN LOWER LOW WATER MLLW = 0.000
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
5799 A 1979 1.771 1.321
ARMY 1951 2.084 1.634
ARMY 1952 NO 1 1966 2.562 2.112
ARMY 1952 NO 2 1966 2.865 2.415
5799 B 1979 2.260 1.810
5799 C 1979 2.408 1.958
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 6 of 6
Station ID: 8745799 PUBLICATION DATE: 02/26/2004
Name: CAT ISLAND, MISSISSIPPI SOUND
MS
NOAA Chart: 11372 Latitude: 30° 13.9' N ( 30.23170)
USGS Quad: CAT ISLAND Longitude: 89° 7.0' W ( -89.11670)
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.