U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 5
Station ID: 8776139 PUBLICATION DATE: 10/14/2020
Name: BIRD ISLAND
TX
NOAA Chart: 11308 Latitude: 27° 29.1' N ( 27.48436)
USGS Quad: S. BIRD ISLAND, TX Longitude: 97° 19.1' W ( -97.31811)
To reach the station from the intersection of State Highways 358 and 361 on
Padre Island, travel 17.7 km (11 mi) south on Park Road 22 to the entrance of
Padre Island National Seashore, thence 1.28 km (.8 mi) south on Park Road 22,
turn left at Park Road leading to the boat ramp and follow the road for 2.09 km
(1.3 mi) west to the boat ramp. A boat is required to reach the station.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 90013 A 1991
DESIGNATION: 877 6139 A
MONUMENTATION: Metal Rod VM#: 17539
AGENCY: Texas General Land Office (TGLO) IDB PID:
SETTING CLASSIFICATION: Stainless steel rod OPUS PID#: BBFG57
LATITUDE: 27° 29.0' N ( 27.48369) LONGITUDE: 97° 19.0' W ( -97.31633)
The primary bench mark is a brass survey disk set atop a stainless steel rod
encased in a 6 inch PVC pipe without kickblock marked with a witness post,
located on an easterly Spoil Island of the GIWW, approximately 609 m (1998.0 ft)
north of the intersection of the Bird Island Channel and the GIWW, 170 m (557.7
ft) SE of the gauge, and approximately 15.2 m (49.9 ft) from the water's edge,
is set flush with the surface of the ground and the steel rod is driven 7.6 m
(24.9 ft) into the ground.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 5
Station ID: 8776139 PUBLICATION DATE: 10/14/2020
Name: BIRD ISLAND
TX
NOAA Chart: 11308 Latitude: 27° 29.1' N ( 27.48436)
USGS Quad: S. BIRD ISLAND, TX Longitude: 97° 19.1' W ( -97.31811)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 90013 B 1991
DESIGNATION: 877 6139 B
MONUMENTATION: Metal Rod VM#: 17540
AGENCY: Texas General Land Office (TGLO) IDB PID:
SETTING CLASSIFICATION: Stainless steel rod OPUS PID:
LATITUDE: 27° 29.0' N ( 27.48331) LONGITUDE: 97° 19.0' W ( -97.31697)
The bench mark is a brass survey disk set atop a stainless steel rod encased in
a 6-inch PVC pipe without kickblock and marked with a witness post, is located
on an easterly Spoil Island of the GIWW, 76.2 m (250.0 ft) NE of BM 90013-A
1991, is set flush with the ground, and the steel rod is driven 12.2 m (40.0 ft)
into the ground.
BENCH MARK STAMPING: 90013 C 1991
DESIGNATION: 877 6139 C
MONUMENTATION: Metal Rod VM#: 17541
AGENCY: Texas General Land Office (TGLO) IDB PID#: DP0727
SETTING CLASSIFICATION: Stainless steel rod OPUS PID#: DP0727
LATITUDE: 27° 29.0' N ( 27.48347) LONGITUDE: 97° 18.9' W ( -97.31556)
The bench mark is a brass survey disk set atop a stainless steel rod encased in
a 6-inch PVC pipe without kickblock and marked with a witness post, is located
on an easterly Spoil Island of the GIWW, 76.2 m (250.0 ft) ESE of 90013 C 1991,
is set flush with the ground and the steel rod is driven 15.2 m (49.9 ft) into
the ground.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 5
Station ID: 8776139 PUBLICATION DATE: 10/14/2020
Name: BIRD ISLAND
TX
NOAA Chart: 11308 Latitude: 27° 29.1' N ( 27.48436)
USGS Quad: S. BIRD ISLAND, TX Longitude: 97° 19.1' W ( -97.31811)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 90013 D 1991
DESIGNATION: 90013 D 1991
MONUMENTATION: Metal Rod VM#: 17542
AGENCY: Texas General Land Office (TGLO) IDB PID:
SETTING CLASSIFICATION: Stainless steal rod OPUS PID:
LATITUDE: 27° 29.0' N ( 27.48342) LONGITUDE: 97° 18.9' W ( -97.31481)
The bench mark is a brass survey disk set atop a stainless steel rod encased in
a 6-inch PVC pipe without kickblock marked with a witness post, is located on an
easterly Spoil Island of the GIWW, 76.2 m (250.0 ft) east of bench mark 90013 C
1991, is set flush with the ground and the steel rod is driven 15.2 m (49.9 ft)
into the ground.
BENCH MARK STAMPING: 90013 E 1991
DESIGNATION: 877 6139 E
MONUMENTATION: Metal Rod VM#: 17543
AGENCY: Texas General Land Office (TGLO) IDB PID:
SETTING CLASSIFICATION: Stainless steel rod OPUS PID:
LATITUDE: 27° 29.0' N ( 27.48264) LONGITUDE: 97° 19.0' W ( -97.31719)
The bench mark is a brass survey disk set atop a stainless steel rod encased in
a 6-inch PVC pipe without kickblock marked with a 2" x 2" wooden stake, located
on an easterly Spoil Island of the GIWW, 76.2 m (250.0 ft) SSE of bench mark
90013 A 1991, set flush with the ground driven 12.2 m (40.0 ft) into the ground.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 5
Station ID: 8776139 PUBLICATION DATE: 10/14/2020
Name: BIRD ISLAND
TX
NOAA Chart: 11308 Latitude: 27° 29.1' N ( 27.48436)
USGS Quad: S. BIRD ISLAND, TX Longitude: 97° 19.1' W ( -97.31811)
T I D A L D A T U M S
Tidal datums at BIRD ISLAND based on:
LENGTH OF SERIES: 1 YEAR
TIME PERIOD: January 2017 - December 2017
TIDAL EPOCH: 2002-2006
CONTROL TIDE STATION: 8775792 PACKERY CHANNEL
Elevations of tidal datums referred to Mean Sea Level (MSL), in METERS:
MEAN SEA LEVEL MSL = 0.000
North American Vertical Datum NAVD88 = -0.174
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MSL
90013 A 1991 0.348
90013 B 1991 0.281
90013 C 1991 0.429
90013 D 1991 0.438
90013 E 1991 0.248
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 5
Station ID: 8776139 PUBLICATION DATE: 10/14/2020
Name: BIRD ISLAND
TX
NOAA Chart: 11308 Latitude: 27° 29.1' N ( 27.48436)
USGS Quad: S. BIRD ISLAND, TX Longitude: 97° 19.1' W ( -97.31811)
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.