U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 6
Station ID: 8775237 PUBLICATION DATE: 12/30/2020
Name: PORT ARANSAS
TX
NOAA Chart: 11309 Latitude: 27° 50.4' N ( 27.83970)
USGS Quad: PORT ARANSAS Longitude: 97° 4.4' W ( -97.07250)
To reach the tidal bench marks, from the U.S Post office in Port Aransas go
southwest on Allister Street for 1.6 km (0.1 mi) to the junction of FM 361, turn
right onto FM 361 and go 1.6 km (1mi) to junction with Port Street on the left,
near the intersection of FM 361 and Cotter Avenue, turn onto Prot Street and go
0.5 km (0.3 mi) to entrance gate of the "Marine Science Institute-Fisheries and
Mariculture Laboratory" operated by the University of Texas in cooperation with
Texas A&M University, after entering the gate, make an immediate left turn in
front of the main Administration Building and then make a right turn and follow
the street along the west side of the Administration Building for 0.2 km (0.1
mi) to the concrete bulkhead and pier. The tide staff is 31 m (101 ft) seaward
from the bulk head.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 90009 D
DESIGNATION: 877 5237 D TIDAL
MONUMENTATION: Bench Mark disk VM#: 16814
AGENCY: Conrad Blucher Institute (CBI) IDB PID#: AC8431
SETTING CLASSIFICATION: Stainless steel rod OPUS PID#: AC8431
LATITUDE: 27° 50.3' N ( 27.83819) LONGITUDE: 97° 4.4' W ( -97.07278)
The primary bench mark is a disk crimped to a stainless steel rod located 24.6 m
(80.7 ft) SSW of the SW corner of the Administration building, 5.8 m (18.0 ft)
north of the chain link fence, 5.5 m (18.0 ft) SE of the SE corner of a
sidewalk, 5.0 m (16.4 ft) west of the centerline of the exit drivewavey, and 0.6
M (2.0 ft) SW of the curb. The stainless steel rod is driven 14.6 m (47.9 ft)
to refusal and encased in 6-inch PVC pipe.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 6
Station ID: 8775237 PUBLICATION DATE: 12/30/2020
Name: PORT ARANSAS
TX
NOAA Chart: 11309 Latitude: 27° 50.4' N ( 27.83970)
USGS Quad: PORT ARANSAS Longitude: 97° 4.4' W ( -97.07250)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 90009 C
DESIGNATION: 877 5237 C TIDAL
MONUMENTATION: Bench Mark disk VM#: 16815
AGENCY: Conrad Blucher Institute (CBI) IDB PID#: AC8429
SETTING CLASSIFICATION: Stainless steel rod OPUS PID#: AC8429
LATITUDE: 27° 50.3' N ( 27.83889) LONGITUDE: 97° 4.4' W ( -97.07283)
The bench mark is a brass disk crimped to the top of a stainless steel rod
located 18.7 m (61.4 ft) SE of the SE corner of the TAMU building, 14.2 m (46.6
ft) NE of the NE corner of the Mariculture Laboratory, 4.6 m (15.1 ft) south of
the center of the driveway, 4.1 m (13.5 ft) west of the road centerline The
bench mark is driven 13.4 m (44 ft) to refusal, set 0.2 m (0.7 ft) above the
level of the road, and encased in a 6 inch PVC pipe.
BENCH MARK STAMPING: 90009 E
DESIGNATION: 877 5237 E TIDAL
MONUMENTATION: Bench Mark disk VM#: 16816
AGENCY: Conrad Blucher Institute (CBI) IDB PID#: AC8432
SETTING CLASSIFICATION: Stainless steel rod OPUS PID#: AC8432
LATITUDE: 27° 50.3' N ( 27.83825) LONGITUDE: 97° 4.3' W ( -97.07194)
The bench mark is a brass disk crimped to a stainless steel rod located 17.0 m
(55.8 ft) SE of the SE corner of the administration building, 6.3 m (20.7 ft)
west of the entry road centerline, 5.3 m (17.4 ft) north of the center of a
gate, and 0.7 m (2.3 ft) south of the south curb of a paved road. The benchmark
is set 0.1 m (0.3 ft) below ground and the stainless steel rod is driven 14.6 m
(47.9 ft) to refusal, and encased in a 5-inch PVC pipe with concrete kickblock.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 6
Station ID: 8775237 PUBLICATION DATE: 12/30/2020
Name: PORT ARANSAS
TX
NOAA Chart: 11309 Latitude: 27° 50.4' N ( 27.83970)
USGS Quad: PORT ARANSAS Longitude: 97° 4.4' W ( -97.07250)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 90009 F 1996
DESIGNATION: 877 5237 F TIDAL
MONUMENTATION: Bench Mark disk VM#: 16817
AGENCY: Conrad Blucher Institute (CBI) IDB PID#: DP0722
SETTING CLASSIFICATION: Stainless steel rod OPUS PID:
LATITUDE: 27° 50.4' N ( 27.83947) LONGITUDE: 97° 4.3' W ( -97.07244)
The bench mark is a brass survey disk crimped to a stainless steel rod located
24.2 m (79.4 ft) NE of the NW corner of the hatchery building slab, 5.4 m (17.7
ft) west of the fifth saltwater well from the west end of a row of eight wells
running parallel to the bulkhead, 3.0 m (9.8 ft) north of the SE corner of a
concrete slab surrounding a storm drain on the inside of the bulkhead, 1.5 m
(4.9 ft) from the outside face of the bulkhead. The bench mark is 0.03 m above
the surface of the ground and the stainless steel rod is driven 13.7 m (45 ft)
to refusal and encased in a 6-inch pvc pipe and concrete kickblock.
BENCH MARK STAMPING: BM 2 ELEV 5.99 1972
DESIGNATION: 877 5237 TIDAL 2
MONUMENTATION: Tidal Station disk VM#: 16818
AGENCY: US Geological Survey IDB PID#: AC8428
SETTING CLASSIFICATION: Concrete seawall OPUS PID#: AC8428
LATITUDE: 27° 50.4' N ( 27.83942) LONGITUDE: 97° 4.4' W ( -97.07275)
The bench mark is a disk set in the concrete seawall located 8.2 m (26.9 ft)
east of the driveway centerline, 5.79 m (19.01 ft) NNE of a small pump building,
0.6 m (2.0 ft) south of the the ship channel. The bench mark is 0.2 m (0.7 ft)
below the level of the road.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 6
Station ID: 8775237 PUBLICATION DATE: 12/30/2020
Name: PORT ARANSAS
TX
NOAA Chart: 11309 Latitude: 27° 50.4' N ( 27.83970)
USGS Quad: PORT ARANSAS Longitude: 97° 4.4' W ( -97.07250)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: BM 3 ELEV 12.6
DESIGNATION: 877 5237 TIDAL 3
MONUMENTATION: Tidal Station disk VM#: 16819
AGENCY: US Geological Survey IDB PID#: AC8430
SETTING CLASSIFICATION: Retaining wall OPUS PID:
LATITUDE: 27° 50.3' N ( 27.83856) LONGITUDE: 97° 4.4' W ( -97.07267)
The bench mark is a brass disk set on top of a concrete wall located 11.1 m
(36.4 ft) east of the road centerline, 7.4 m (24.3 ft) north of the NW corner of
the administration building 2.6 m (8.5 ft) south of the north end of the north
concrete retaining wall of a loading dock at the NW corner of the administration
building. The bench mark is set 1.6 m (5.2 ft) above the level of the road.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 6
Station ID: 8775237 PUBLICATION DATE: 12/30/2020
Name: PORT ARANSAS
TX
NOAA Chart: 11309 Latitude: 27° 50.4' N ( 27.83970)
USGS Quad: PORT ARANSAS Longitude: 97° 4.4' W ( -97.07250)
T I D A L D A T U M S
Tidal datums at PORT ARANSAS based on:
LENGTH OF SERIES: 3 YEARS
TIME PERIOD: September 2016 - August 2019
TIDAL EPOCH: 1983-2001
CONTROL TIDE STATION: 8779770 PORT ISABEL, LAGUNA MADRE
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
HIGHEST OBSERVED WATER LEVEL (08/26/2017) = 1.899
MEAN HIGHER HIGH WATER MHHW = 0.318
MEAN HIGH WATER MHW = 0.308
MEAN SEA LEVEL MSL = 0.197
MEAN TIDE LEVEL MTL = 0.173
North American Vertical Datum NAVD88 = 0.045
MEAN LOW WATER MLW = 0.037
MEAN LOWER LOW WATER MLLW = 0.000
LOWEST OBSERVED WATER LEVEL (01/01/2003) = -0.407
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
90009 D 2.119 1.811
90009 C 2.384 2.076
90009 E 2.242 1.934
90009 F 1996 1.980 1.672
BM 2 ELEV 5.99 1972 2.106 1.798
BM 3 ELEV 12.6 4.039 3.731
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 6 of 6
Station ID: 8775237 PUBLICATION DATE: 12/30/2020
Name: PORT ARANSAS
TX
NOAA Chart: 11309 Latitude: 27° 50.4' N ( 27.83970)
USGS Quad: PORT ARANSAS Longitude: 97° 4.4' W ( -97.07250)
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.