U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 6
Station ID: 8771972 PUBLICATION DATE: 05/21/2021
Name: SAN LUIS PASS, WEST BAY
TX
NOAA Chart: 11322 Latitude: 29° 4.9' N ( 29.08097)
USGS Quad: CHRISTMAS POINT Longitude: 95° 7.9' W ( -95.13133)
TO REACH THE STATION FROM THE TOLL BOOTH ON THE EAST SIDE OF THE SAN LUIS PASS
BRIDGE, GO SOUTHWEST 2.33 KM (1.45 MI) ACROSS BRIDGE TO THE FIRST ROAD ON THE
RIGHT ON THE WEST SIDE OF THE SAN LUIS PASS BRIDGE. TURN RIGHT ONTO FEEDER ROAD
AND MAKE AN IMMEDIATE LEFT, EAST, 0.2 KM (0.10 MI) TO THE SAN LUIS PASS FISHING
PIER. THE BENCHMARKS ARE LOCATED WITHIN THE PARK GROUNDS STARTING NEAR THE
ENTRANCE AND ENDING AT THE TIDE STATION.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 1972 M 2010
DESIGNATION: 877 1972 M
ALIAS: 1972 M 2010
MONUMENTATION: Metal Rod VM#: 20478
AGENCY: Conrad Blucher Institute (CBI) IDB PID#: DP0696
SETTING CLASSIFICATION: Stainless steel rod OPUS PID#: DP0696
LATITUDE: 29° 4.8' N ( 29.08019) LONGITUDE: 95° 7.9' W ( -95.13222)
The bench mark is located 148 m (485.6 ft) SW of the tide station, 21.3 m (69.9
ft) SW of the south corner of the restroom building, 14.19 m (46.5 ft) west of a
light pole, and 7.0 m (22.9 ft) SW of a concrete drain cap numbered V-1418. The
datum point is the top of a stainless steel rod is driven 17.1 m (56 ft) to
refusal and encased in 6 inch PVC with a CBI logo cap.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 6
Station ID: 8771972 PUBLICATION DATE: 05/21/2021
Name: SAN LUIS PASS, WEST BAY
TX
NOAA Chart: 11322 Latitude: 29° 4.9' N ( 29.08097)
USGS Quad: CHRISTMAS POINT Longitude: 95° 7.9' W ( -95.13133)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 1972 N 2010
DESIGNATION: 877 1972 N 2010
ALIAS: 1972 N 2010
MONUMENTATION: Metal Rod VM#: 21992
AGENCY: Conrad Blucher Institute (CBI) IDB PID:
SETTING CLASSIFICATION: Stainless steel rod OPUS PID:
LATITUDE: 29° 4.8' N ( 29.07967) LONGITUDE: 95° 7.9' W ( -95.13092)
The bench mark is located 8.0 m (26.2 ft) north of the centerline of road on the
island, 4.52 m (14.83 ft) east of light pole with street light, and 1.7 m (5.6
ft) NNE of a 1.5 m (4.9 ft) x 1.5 m (4.9 ft) concrete 480 volt conduit that
houses power to the RV park. The datum point is the top of a stainless steel
deep-rod driven 17.1 m (56 ft) to refusal and encased in 6 inch PVC with a CBI
logo cap.
BENCH MARK STAMPING: 1972 I 2009
DESIGNATION: 877 1972 I
ALIAS: 1972 I
MONUMENTATION: Bench Mark disk VM#: 21993
AGENCY: Conrad Blucher Institute (CBI) IDB PID:
SETTING CLASSIFICATION: Concrete bulkhead OPUS PID:
LATITUDE: 29° 4.8' N ( 29.07936) LONGITUDE: 95° 7.8' W ( -95.13053)
The bench mark is a brass disk set flush in the top of a concrete bulkhead,
located 62 m (203.4 ft) north of the boat ramp on the bulkhead, 22.3 m (73.2 ft)
NW of the most southern corner of the laundry room, and 9.2 m (30.2 ft) SSW of
the centerline of the wooden bridge.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 6
Station ID: 8771972 PUBLICATION DATE: 05/21/2021
Name: SAN LUIS PASS, WEST BAY
TX
NOAA Chart: 11322 Latitude: 29° 4.9' N ( 29.08097)
USGS Quad: CHRISTMAS POINT Longitude: 95° 7.9' W ( -95.13133)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 1972 J 2009
DESIGNATION: 877 1972 J
ALIAS: 1972 J 2009
MONUMENTATION: Bench Mark disk VM#: 21994
AGENCY: Conrad Blucher Institute (CBI) IDB PID:
SETTING CLASSIFICATION: Sidewalk OPUS PID:
LATITUDE: 29° 4.7' N ( 29.07906) LONGITUDE: 95° 7.8' W ( -95.13000)
The bench mark is located 27.1 m (88.9 ft) south of the centerline of road to
enter the campground, 20 m (65.6 ft) east of the administration building, 16.68
m (54.7 ft) north of the northern edge of parking lot, and 2.25 m (7.4ft) south
of the southern side of playground. The bench mark is a brass disk set flush in
the top of a concrete sidewalk.
BENCH MARK STAMPING: 1972 P 2010
DESIGNATION: 877 1972 P 2010
ALIAS: 1972 P 2010
MONUMENTATION: Metal Rod VM#: 21995
AGENCY: Conrad Blucher Institute (CBI) IDB PID:
SETTING CLASSIFICATION: Stainless steel rod OPUS PID:
LATITUDE: 29° 4.8' N ( 29.07922) LONGITUDE: 95° 7.8' W ( -95.12956)
The bench mark is located 16.64 m (54.59 ft) SW of a Marlin Open Pavillion,
11.0 m (36.1 ft) east of an elevated well house, and 4.85 m (15.9 ft) east of
centerline of Park Entrance Road. The datum point is the top of a stainless
steel rod driven 17.1 m (56 ft) to refusal and encased in a 6 inch PVC with a
CBI logo cap.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 6
Station ID: 8771972 PUBLICATION DATE: 05/21/2021
Name: SAN LUIS PASS, WEST BAY
TX
NOAA Chart: 11322 Latitude: 29° 4.9' N ( 29.08097)
USGS Quad: CHRISTMAS POINT Longitude: 95° 7.9' W ( -95.13133)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 1972 K 2009
DESIGNATION: 877 1972 K
ALIAS: 1972 K
MONUMENTATION: Metal Rod VM#: 21996
AGENCY: Conrad Blucher Institute (CBI) IDB PID:
SETTING CLASSIFICATION: Stainless steel rod OPUS PID#: BBBS79
LATITUDE: 29° 4.7' N ( 29.07756) LONGITUDE: 95° 7.7' W ( -95.12772)
The bench mark is located 64.37 m (211.18 ft) west of the centerline of the
highway, 25.12 m (82.4 ft) NW of the north side of county park sign, 3 m (9.8
ft) SW from centerline of road entering into the park, and 1.0 m (3.3 ft) west
of witness post. The datum point is the top of an stainless steel rod driven
13.4 m (44.0 ft) to refusal and encased in 6 inch PVC with CBI logo cap.
BENCH MARK STAMPING: 1972 G 2009
DESIGNATION: 877 1972 G
ALIAS: 1972 G
MONUMENTATION: Bench Mark disk VM#: 21997
AGENCY: Conrad Blucher Institute (CBI) IDB PID:
SETTING CLASSIFICATION: Concrete bulkhead OPUS PID:
LATITUDE: 29° 4.9' N ( 29.08094) LONGITUDE: 95° 7.9' W ( -95.13128)
The bench mark is a disk set in concrete bulkhead. The bench mark is located
35.46 m (116.34 ft) north west of tide gauge on concrete bulkhead, 25.4 m (83.3
ft) ESE of light pole, 13.3 m (43.6 ft) SE of the west corner of the end of the
bulkhead.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 6
Station ID: 8771972 PUBLICATION DATE: 05/21/2021
Name: SAN LUIS PASS, WEST BAY
TX
NOAA Chart: 11322 Latitude: 29° 4.9' N ( 29.08097)
USGS Quad: CHRISTMAS POINT Longitude: 95° 7.9' W ( -95.13133)
T I D A L D A T U M S
Tidal datums at SAN LUIS PASS, WEST BAY based on:
LENGTH OF SERIES: 2 YEARS
TIME PERIOD: 10/2016-09/2017, 04/2019-03/2020
TIDAL EPOCH: 1983-2001
CONTROL TIDE STATION: 8771450 GALVESTON PIER 21, GALVESTON CHANNEL
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
HIGHEST OBSERVED WATER LEVEL (09/21/2020) = 1.676
MEAN HIGHER HIGH WATER MHHW = 0.356
MEAN HIGH WATER MHW = 0.338
MEAN SEA LEVEL MSL = 0.209
MEAN TIDE LEVEL MTL = 0.201
North American Vertical Datum NAVD88 = 0.077
MEAN LOW WATER MLW = 0.065
MEAN LOWER LOW WATER MLLW = 0.000
LOWEST OBSERVED WATER LEVEL (01/12/2018) = -0.779
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
1972 M 2010 0.979 0.641
1972 N 2010 1.038 0.700
1972 I 2009 1.415 1.077
1972 J 2009 1.832 1.494
1972 P 2010 2.067 1.729
1972 K 2009 1.017 0.679
1972 G 2009 1.685 1.347
Foot Notes:
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 6 of 6
Station ID: 8771972 PUBLICATION DATE: 05/21/2021
Name: SAN LUIS PASS, WEST BAY
TX
NOAA Chart: 11322 Latitude: 29° 4.9' N ( 29.08097)
USGS Quad: CHRISTMAS POINT Longitude: 95° 7.9' W ( -95.13133)
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.