U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 5
Station ID: 8762273 PUBLICATION DATE: 02/13/2004
Name: EAST END, PASS MANCHAC
LA
NOAA Chart: 11369 Latitude: 30° 17.8' N ( 30.29670)
USGS Quad: PANCHATOULA SE Longitude: 90° 18.7' W ( -90.31170)
To reach the tidal bench marks from the public boat ramp just north of Manchac
on U.S. Highway 51, proceed by boat 1.3 km (0.9 nm) south on a canal parallel to
Interstate Highway 55 to Pass Manchac, then continue east on Pass Manchac for
7.4 km (5.3 nm) to the Murray camp on the north shore. The bench marks are east
and west of the Murray camp. The tide gage and staff were located at the SE
corner of the Murray pier.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 2273B 1982
DESIGNATION: 876 2273 B
MONUMENTATION: Tidal Station disk VM#: 11599
AGENCY: National Ocean Survey (NOS) IDB PID#:
SETTING CLASSIFICATION: Stainless steel rod OPUS PID:
LATITUDE: 30° 17.8' N ( 30.29670) LONGITUDE: 90° 18.7' W ( -90.31170)
The primary bench mark is a disk located near the NW corner of the Murray camp
house, 63 m (208 ft) NW of bench mark 2273A 1982, 23 m (76 ft) north of the
approximate high water mark on Pass Manchac, 23 m (76 ft) SE of utility pole
#535, 20 m (65 ft) ENE of the NE corner of Starvation Landing camp house, and 20
m (65 ft) WNW of the NW corner of the Murray camp house. The bench mark is set
0.1 m (0.3 ft) below grade, crimped to a stainless steel rod driven 19.5 m (64
ft) to substantial resistance, and encased in a 4-inch PVC collar and concrete
kickblock.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 5
Station ID: 8762273 PUBLICATION DATE: 02/13/2004
Name: EAST END, PASS MANCHAC
LA
NOAA Chart: 11369 Latitude: 30° 17.8' N ( 30.29670)
USGS Quad: PANCHATOULA SE Longitude: 90° 18.7' W ( -90.31170)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 2273C 1982
DESIGNATION: 876 2273 C
MONUMENTATION: Tidal Station disk VM#: 11600
AGENCY: National Ocean Survey (NOS) IDB PID#:
SETTING CLASSIFICATION: Stainless steel rod OPUS PID:
LATITUDE: 30° 17.8' N ( 30.29670) LONGITUDE: 90° 18.7' W ( -90.31170)
The bench mark is a disk located 55 m (182 ft) west of bench mark 2273B 1982, 33
m (109 ft) south of utility pole #534, and 8 m (27 ft) NNE of a wooden bulkhead.
The bench mark is set 0.1 m (0.3 ft) below grade, crimped to a stainless steel
rod driven 20.7 m (68 ft) to substantial resistance, and encased in a 4-inch PVC
collar and concrete kickblock.
BENCH MARK STAMPING: 2273D 1982
DESIGNATION: 876 2273 D
MONUMENTATION: Tidal Station disk VM#: 11601
AGENCY: National Ocean Survey (NOS) IDB PID#:
SETTING CLASSIFICATION: Stainless steel rod OPUS PID:
LATITUDE: 30° 17.8' N ( 30.29670) LONGITUDE: 90° 18.7' W ( -90.31170)
The bench mark is a disk located west of bench mark 2273C 1982, 23 m (75 ft) NW
of an unmarked light pole, 17 m (55 ft) WNW of the SW corner of the second camp
west of Starvation Landing camp, 10 m (32 ft) NNE of the approximate high water
mark on the north shore of Pass Manchac, and 6 m (19 ft) ESE of the SE corner of
the third camp west of Starvation Landing camp. The bench mark is set 0.1 m
(0.3 ft) below grade, crimped to a stainless steel rod driven 19.5 m (64 ft) to
substantial resistance, and encased in a 4-inch PVC collar and concrete
kickblock.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 5
Station ID: 8762273 PUBLICATION DATE: 02/13/2004
Name: EAST END, PASS MANCHAC
LA
NOAA Chart: 11369 Latitude: 30° 17.8' N ( 30.29670)
USGS Quad: PANCHATOULA SE Longitude: 90° 18.7' W ( -90.31170)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 2273E 1982
DESIGNATION: 876 2273 E
MONUMENTATION: Tidal Station disk VM#: 11602
AGENCY: National Ocean Survey (NOS) IDB PID#:
SETTING CLASSIFICATION: Stainless steel rod OPUS PID:
LATITUDE: 30° 17.8' N ( 30.29670) LONGITUDE: 90° 18.7' W ( -90.31170)
The bench mark is a disk, 62 m (204 ft) WNW of bench mark 2273D 1982, 26 m (85
ft) NW of the NW corner of a small wooden camp house, 5 m (18 ft) NNE of a 0.46
m (1.5 ft) diameter oak tree, and 2 m (7 ft) ESE of the approximate high water
mark on the east bank of a small unnamed bayou. The bench mark is set 0.1 m
(0.3 ft) below ground level, crimped to a stainless steel rod driven 19.5 m (64
ft) to substantial resistance, and encased in a 4-inch PVC collar and concrete
kickblock.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 5
Station ID: 8762273 PUBLICATION DATE: 02/13/2004
Name: EAST END, PASS MANCHAC
LA
NOAA Chart: 11369 Latitude: 30° 17.8' N ( 30.29670)
USGS Quad: PANCHATOULA SE Longitude: 90° 18.7' W ( -90.31170)
T I D A L D A T U M S
Tidal datums at EAST END, PASS MANCHAC based on:
LENGTH OF SERIES: 5 YEARS
TIME PERIOD: January 1983 - December 1987
TIDAL EPOCH: 1983-2001
CONTROL TIDE STATION: 8761927 USCG NEW CANAL STA., LAKE PONT.
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
HIGHEST OBSERVED WATER LEVEL (01/20/1983) = 0.877
MEAN HIGHER HIGH WATER MHHW = 0.154
MEAN HIGH WATER MHW = 0.153
MEAN SEA LEVEL MSL = 0.079
MEAN TIDE LEVEL MTL = 0.077
MEAN LOW WATER MLW = 0.000
MEAN LOWER LOW WATER MLLW = 0.000
LOWEST OBSERVED WATER LEVEL (04/12/1988) = -0.791
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
2273B 1982 0.345 0.192
2273C 1982 0.345 0.192
2273D 1982 0.352 0.199
2273E 1982 0.486 0.333
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 5
Station ID: 8762273 PUBLICATION DATE: 02/13/2004
Name: EAST END, PASS MANCHAC
LA
NOAA Chart: 11369 Latitude: 30° 17.8' N ( 30.29670)
USGS Quad: PANCHATOULA SE Longitude: 90° 18.7' W ( -90.31170)
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.