U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 4
Station ID: 8765148 PUBLICATION DATE: 02/26/2004
Name: WEEKS BAY
LA
NOAA Chart: 11349 Latitude: 29° 48.7' N ( 29.81170)
USGS Quad: WEEKS Longitude: 91° 49.6' W ( -91.82670)
To reach the tidal bench marks from the intersection of State Highway 49/US Hwy
90 and Lewis Road in New Iberia, proceed south 2.2 km (1.4 mi) to the public
boat ramp, then proceed by boat WSW for 0.8 km (0.5 mi) to the New Iberia
Drainage Canal, then follow it south for 10.5 km (6.5 mi) to the Gulf
Intracoastal Waterway (ICWW). The bench marks are located in the vicinity of
Bayou Carlin, where the drainage canal joins the ICWW. The tide gage was located
approximately 275 m (900 ft) SE of the drainage canal on the ICWW.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: CARLIN
DESIGNATION: 876 5148 CARLIN
MONUMENTATION: Flange-encased Rod VM#: 16565
AGENCY: John Chance Surveyors IDB PID#:
SETTING CLASSIFICATION: Stainless steel rod in sleeve OPUS PID:
LATITUDE: 29° 50.4' N ( 29.84000) LONGITUDE: 91° 50.4' W ( -91.84000)
The bench mark is a flange-encased rod set on the south spoil bank on the Gulf
Intracoastal Waterway, approximately 213 m (700 ft) SE of the Bayou Carlin cut.
The bench mark is a survey disk set 30 cm (1.0 ft)above ground level, crimped to
the top of a stainless steel rod driven an unspecified depth, and encased in a
sleeve to a depth of 1 m (3 ft) and a NGS logo cap.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 4
Station ID: 8765148 PUBLICATION DATE: 02/26/2004
Name: WEEKS BAY
LA
NOAA Chart: 11349 Latitude: 29° 48.7' N ( 29.81170)
USGS Quad: WEEKS Longitude: 91° 49.6' W ( -91.82670)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 5148 A 01
DESIGNATION: 876 5148 A
MONUMENTATION: Flange-encased Rod VM#: 16566
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Stainless steel rod OPUS PID:
LATITUDE: 29° 50.4' N ( 29.84000) LONGITUDE: 91° 50.4' W ( -91.84000)
The bench mark is a flange-encased rod set in the NW part of Bayou Carlin, 33.83
m (111 ft) SE of bench mark CARLIN, 3.65 m (12.0 ft) south of the bank of the
Gulf Intracoastal Waterway, and 0.61 m (2.0 ft) ENE of of a witness post. The
datum point is set 20 cm (0.6 ft) above ground level, being the top of a
stainless steel rod driven 12.8 meters (42 ft) to refusal and encased in a 5
inch PVC pipe and NOS logo cap.
BENCH MARK STAMPING: 5148 B 01
DESIGNATION: 876 5148 B
MONUMENTATION: Flange-encased Rod VM#: 16567
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Stainless steel rod OPUS PID:
LATITUDE: 29° 50.4' N ( 29.84000) LONGITUDE: 91° 50.4' W ( -91.84000)
The bench mark is a flange-encased rod set 54.56 m (179.0 ft) SW of bench mark
CARLIN, 15.24 m (50.0 ft) east of a 12 inch china ball tree, and 0.76 m (2.5 ft)
SSE of a witness post. The datum point is 25 cm (0.8 ft) above ground level,
being the top of a stainless steel rod driven 14.30 m (46.9 ft) to refusal and
encased in a 5 inch PVC pipe and NOS logo cap.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 4
Station ID: 8765148 PUBLICATION DATE: 02/26/2004
Name: WEEKS BAY
LA
NOAA Chart: 11349 Latitude: 29° 48.7' N ( 29.81170)
USGS Quad: WEEKS Longitude: 91° 49.6' W ( -91.82670)
T I D A L D A T U M S
Tidal datums at WEEKS BAY based on:
LENGTH OF SERIES: 1 MONTH
TIME PERIOD: August 2001 - September 2001
TIDAL EPOCH: 1983-2001
CONTROL TIDE STATION: 8771510 GALVESTON PLEASURE PIER, GULF OF MEXICO
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
MEAN HIGHER HIGH WATER MHHW = 0.490
MEAN HIGH WATER MHW = 0.463
MEAN SEA LEVEL MSL = 0.271
MEAN TIDE LEVEL MTL = 0.269
MEAN LOW WATER MLW = 0.076
MEAN LOWER LOW WATER MLLW = 0.000
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
CARLIN 0.836 0.373
5148 A 01 0.719 0.256
5148 B 01 0.768 0.305
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 4
Station ID: 8765148 PUBLICATION DATE: 02/26/2004
Name: WEEKS BAY
LA
NOAA Chart: 11349 Latitude: 29° 48.7' N ( 29.81170)
USGS Quad: WEEKS Longitude: 91° 49.6' W ( -91.82670)
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.