U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 6
Station ID: 8778485 PUBLICATION DATE: 05/27/2021
Name: PADRE ISLAND, PORT MANSFIELD CHANNEL ENTRANCE
TX
NOAA Chart: 11306 Latitude: 26° 33.9' N ( 26.56420)
USGS Quad: SOUTH OF PORTRERO LOPENO SE Longitude: 97° 16.6' W ( -97.27650)
To reach from the U.S. Post Office located at 800 Mansfield Dr in Port
Mansfield, TX, proceed northeast on TX-186 E for 0.39 Km (0.24 mi) to the the
public boat ramp on the right side of the road, then proceed east by boat
following the marked channel 15.4 Km (9.6 mi) to the north jetty of the Port
Mansfield Channel through Padre Island. The bench marks are located along the
north jetty and to the north along the eastern shore of Padre Island. The tide
gauge was located on the north jetty.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 532
DESIGNATION: 532
MONUMENTATION: Survey disk VM#: 23387
AGENCY: US Army Corps of Engineers (USACE) IDB PID#: AB1709
SETTING CLASSIFICATION: OPUS PID#: AB1709
LATITUDE: 26° 33.9' N ( 26.56494) LONGITUDE: 97° 16.6' W ( -97.27631)
The primary bench mark is a disk set in a granite boulder near the western end
of the north jetty, 275.9 m (905.2 ft) west of bench mark 877 8485 B, 83.56 m
(274.1 ft) north of the U.S. Coast guard light number 6, and 60.00 m (196.9 ft)
east of the western end of the north jetty.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 6
Station ID: 8778485 PUBLICATION DATE: 05/27/2021
Name: PADRE ISLAND, PORT MANSFIELD CHANNEL ENTRANCE
TX
NOAA Chart: 11306 Latitude: 26° 33.9' N ( 26.56420)
USGS Quad: SOUTH OF PORTRERO LOPENO SE Longitude: 97° 16.6' W ( -97.27650)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 8485 A 2019
DESIGNATION: 877 8485 A
MONUMENTATION: Tidal Station disk VM#: 23388
AGENCY: National Ocean Service (NOS) IDB PID:
SETTING CLASSIFICATION: OPUS PID:
LATITUDE: 26° 33.9' N ( 26.56517) LONGITUDE: 97° 16.2' W ( -97.27042)
The bench mark is a disk set in a granite boulder near the eastern end of the
north jetty, 312.0 m (1023.6 ft) east of bench mark 877 8485 B, 23.40 m (76.8
ft) west of the eastern end of the north jetty, 9.30 m (30.5 ft) west of the
USCG light at the eastern end of the jetty, and 5.22 m (17.1 ft) west of an 8-in
(20 cm) steel post.
BENCH MARK STAMPING: 8485 B 2019
DESIGNATION: 877 8485 B
MONUMENTATION: Tidal Station disk VM#: 23389
AGENCY: National Ocean Service (NOS) IDB PID:
SETTING CLASSIFICATION: OPUS PID:
LATITUDE: 26° 33.9' N ( 26.56503) LONGITUDE: 97° 16.4' W ( -97.27356)
The bench mark is a disk set in a granite boulder near the middle of the north
jetty, 322.0 m (1056.4 ft) west of an 8-in (20 cm) stainless steel post for U.S.
Coast Guard light number 2 at the eastern end of the jetty, 312.0 m (1023.6 ft)
west of bench mark 877 8485 A, 307.0 m (1007.2 ft) ENE of U.S. Coast guard light
number 6, and 275.9 m (905.2 ft) east of bench mark 532.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 6
Station ID: 8778485 PUBLICATION DATE: 05/27/2021
Name: PADRE ISLAND, PORT MANSFIELD CHANNEL ENTRANCE
TX
NOAA Chart: 11306 Latitude: 26° 33.9' N ( 26.56420)
USGS Quad: SOUTH OF PORTRERO LOPENO SE Longitude: 97° 16.6' W ( -97.27650)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: WALKER
DESIGNATION: WALKER
MONUMENTATION: Metal Rod VM#: 23390
AGENCY: IDB PID:
SETTING CLASSIFICATION: OPUS PID#: BBGJ48
LATITUDE: 26° 34.1' N ( 26.56817) LONGITUDE: 97° 16.7' W ( -97.27897)
The bench mark is a rod set to the north of the north jetty on Padre Island,
400.0 m (1312.3 ft) NNW of the Port Mansfield cut, 92.98 m (305.1 ft) north of
bench mark Leigh, 75.00 m (246.1 ft) east of a 10-ft in diameter steel float,
and 20.00 m (65.6 ft) west of the top of the bluff. The datum point is set 10
cm (4 inches) below ground, being the top of a stainless steel rod driven to an
unspecified depth and encased in a PVC pipe.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 6
Station ID: 8778485 PUBLICATION DATE: 05/27/2021
Name: PADRE ISLAND, PORT MANSFIELD CHANNEL ENTRANCE
TX
NOAA Chart: 11306 Latitude: 26° 33.9' N ( 26.56420)
USGS Quad: SOUTH OF PORTRERO LOPENO SE Longitude: 97° 16.6' W ( -97.27650)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: LEIGH 1980
DESIGNATION: LEIGH
MONUMENTATION: Horizontal Station disk VM#: 23391
AGENCY: National Geodetic Survey (NGS) IDB PID#: AB1409
SETTING CLASSIFICATION: OPUS PID:
LATITUDE: 26° 34.0' N ( 26.56733) LONGITUDE: 97° 16.7' W ( -97.27908)
The bench mark is a disk set in a concrete monument to the north of the north
jetty on Padre Island, 320.0 m (1049.9 ft) north of the Port Mansfield cut,
92.98 m (305.1 ft) south of bench mark WALKER, 65.00 m (213.3 ft) west of the
top of the bluff, 15.13 m (49.6 ft) north of of reference mark Leigh no 1, and
5.21 m (17.1 ft) west of city service mark.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 6
Station ID: 8778485 PUBLICATION DATE: 05/27/2021
Name: PADRE ISLAND, PORT MANSFIELD CHANNEL ENTRANCE
TX
NOAA Chart: 11306 Latitude: 26° 33.9' N ( 26.56420)
USGS Quad: SOUTH OF PORTRERO LOPENO SE Longitude: 97° 16.6' W ( -97.27650)
T I D A L D A T U M S
Tidal datums at PADRE ISLAND, PORT MANSFIELD CHANNEL ENTRANCE based on:
LENGTH OF SERIES: 5 MONTHS
TIME PERIOD: January 2020 - May 2020
TIDAL EPOCH: 1983-2001
CONTROL TIDE STATION: 8775870 BOB HALL PIER, CORPUS CHRISTI
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
MEAN HIGHER HIGH WATER MHHW = 0.438
MEAN HIGH WATER MHW = 0.420
North American Vertical Datum NAVD88 = 0.292
MEAN SEA LEVEL MSL = 0.257
MEAN TIDE LEVEL MTL = 0.235
MEAN LOW WATER MLW = 0.050
MEAN LOWER LOW WATER MLLW = 0.000
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
532 2.785 2.365
8485 A 2019 2.882 2.462
8485 B 2019 2.401 1.981
WALKER 3.204 2.784
LEIGH 1980 7.199 6.779
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 6 of 6
Station ID: 8778485 PUBLICATION DATE: 05/27/2021
Name: PADRE ISLAND, PORT MANSFIELD CHANNEL ENTRANCE
TX
NOAA Chart: 11306 Latitude: 26° 33.9' N ( 26.56420)
USGS Quad: SOUTH OF PORTRERO LOPENO SE Longitude: 97° 16.6' W ( -97.27650)
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.