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Datums Page Page 1 of 8
Station ID: 8775270 PUBLICATION DATE: 06/02/2003
Name: PORT ARANSAS, H. CALDWELL PIER
TX
NOAA Chart: 11307 Latitude: 27° 49.6' N ( 27.82670)
USGS Quad: PORT ARANSAS Longitude: 97° 3.0' W ( -97.05000)
To reach the tidal bench marks from the Post Office in Port Aransas on South
Allister Street south of C Avenue, proceed north on South Allister Street for
approximately 0.56 km (0.35 mi) to Beach Street, turn right onto Beach Street
and continue east for approximately 1.1 km (0.7 mi) to Horace Caldwell Fishing
Pier. The bench marks are located north of Beach Street. The tide gauge and
staff were located on the old (wooden) Hooke Caldwell Fishing Pier.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: NO 11 1960
DESIGNATION: 877 5270 TIDAL 11
MONUMENTATION: Tidal Station disk VM#: 11194
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#: AH0187
SETTING CLASSIFICATION: Concrete monument OPUS PID:
LATITUDE: 27° 49.8' N ( 27.83000) LONGITUDE: 97° 3.3' W ( -97.05500)
The primary bench mark is a disk set in the top of a concrete monument on the
south side of Beach Street 0.8 km (0.5 mi) east of Station Street, 14.81 m (48.6
ft) NW of the centerline of a paved road leading SW, 14.17 m (46.5 ft) south of
the centerline of Beach Street, 0.91 m (3 ft) east of a witness post, 0.76 m
(2.5 ft) east of a power pole, and level with the ground.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 8
Station ID: 8775270 PUBLICATION DATE: 06/02/2003
Name: PORT ARANSAS, H. CALDWELL PIER
TX
NOAA Chart: 11307 Latitude: 27° 49.6' N ( 27.82670)
USGS Quad: PORT ARANSAS Longitude: 97° 3.0' W ( -97.05000)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: NO 12 1960
DESIGNATION: 877 5270 TIDAL 12
MONUMENTATION: Tidal Station disk VM#: 11195
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#: AH0186
SETTING CLASSIFICATION: Concrete monument OPUS PID:
LATITUDE: 27° 49.9' N ( 27.83170) LONGITUDE: 97° 3.4' W ( -97.05670)
The bench mark is a disk set in the top of a concrete monument on the south side
of Beach Street in the vicinity of the training complex for the University of
Texas Marine Science Institute, 14.14 m (46.4 ft) south of the centerline of
Beach Street, 0.67 m (2.2 ft) east of a power pole (7th power pole west of bench
mark No. 11 1960, and 0.09 m (0.3 ft) above the ground.
BENCH MARK STAMPING: NO 13 1960
DESIGNATION: 877 5270 TIDAL 13
MONUMENTATION: Tidal Station disk VM#: 11196
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#: AH0183
SETTING CLASSIFICATION: Concrete monument OPUS PID:
LATITUDE: 27° 50.0' N ( 27.83330) LONGITUDE: 97° 3.5' W ( -97.05830)
The bench mark is a disk set in the top of a concrete monument on the south side
of Beach Street, east of the intersection of Beach Street and Station Street,
10.97 m (36 ft) east of a line of light poles for a football stadium, 7.62 m
(25.0 ft) south of the centerline of Beach Street, 1.22 m (4 ft) south of a
transformer pole, 0.61 m (2.0 ft) SW of a witness post, and 0.09 m (0.3 ft)
above the ground.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 8
Station ID: 8775270 PUBLICATION DATE: 06/02/2003
Name: PORT ARANSAS, H. CALDWELL PIER
TX
NOAA Chart: 11307 Latitude: 27° 49.6' N ( 27.82670)
USGS Quad: PORT ARANSAS Longitude: 97° 3.0' W ( -97.05000)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: NO 15 1975
DESIGNATION: 877 5270 TIDAL 15
MONUMENTATION: Tidal Station disk VM#: 11197
AGENCY: National Ocean Survey (NOS) IDB PID#: AH0191
SETTING CLASSIFICATION: Concrete sewage tank cover OPUS PID:
LATITUDE: 27° 49.7' N ( 27.82830) LONGITUDE: 97° 3.2' W ( -97.05330)
The bench mark is a disk set in the top of the NE corner of a concrete sewage
tank cover at the eastern end of Beach Street, 7.92 m (26 ft) south of the
centerline of Beach Street, and 0.61 m (2.0 ft) above the road.
BENCH MARK STAMPING: NO 16 1975
DESIGNATION: 877 5270 TIDAL 16
MONUMENTATION: Tidal Station disk VM#: 11198
AGENCY: National Ocean Survey (NOS) IDB PID#: AH0190
SETTING CLASSIFICATION: Concrete retaining wall OPUS PID:
LATITUDE: 27° 49.8' N ( 27.83000) LONGITUDE: 97° 3.3' W ( -97.05500)
The bench mark is a disk set in the top of a concrete retaining wall at the
eastern end of Beach Street, 29.87 m (98.0 ft) east of the centerline of the
road leading to Nueces County Park Office, 15.70 m (51.5 ft)north of the
centerline of Beach Street, and 0.61 m (2.0 ft) above the road.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 8
Station ID: 8775270 PUBLICATION DATE: 06/02/2003
Name: PORT ARANSAS, H. CALDWELL PIER
TX
NOAA Chart: 11307 Latitude: 27° 49.6' N ( 27.82670)
USGS Quad: PORT ARANSAS Longitude: 97° 3.0' W ( -97.05000)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: NO 17 1975
DESIGNATION: 877 5270 TIDAL 17
MONUMENTATION: Tidal Station disk VM#: 11199
AGENCY: National Ocean Survey (NOS) IDB PID#: AH0189
SETTING CLASSIFICATION: Retaining wall OPUS PID:
LATITUDE: 27° 49.8' N ( 27.83000) LONGITUDE: 97° 3.3' W ( -97.05500)
The bench mark is a disk set in the top at the north end of a concrete retaining
wall at the eastern end of Beach Street, 11.40 m (37.4 ft) east of the
centerline of the road leading to Nueces County Park Office, 10.27 m (33.7 ft)
south of the second lamp pole on the park road, and 0.61 m (2.0 ft) above the
road.
BENCH MARK STAMPING: NO 18 1975
DESIGNATION: 877 5270 TIDAL 18
MONUMENTATION: Tidal Station disk VM#: 11200
AGENCY: National Ocean Survey (NOS) IDB PID#: AH0185
SETTING CLASSIFICATION: Concrete manhole OPUS PID:
LATITUDE: 27° 50.0' N ( 27.83330) LONGITUDE: 97° 3.4' W ( -97.05670)
The bench mark is a disk set flush in a concrete manhole on the north side Beach
Street, 600 m (1968.5 ft) west of the fishing pier, and 6.92 m (22.7 ft) north
of the centerline of Beach Street.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 8
Station ID: 8775270 PUBLICATION DATE: 06/02/2003
Name: PORT ARANSAS, H. CALDWELL PIER
TX
NOAA Chart: 11307 Latitude: 27° 49.6' N ( 27.82670)
USGS Quad: PORT ARANSAS Longitude: 97° 3.0' W ( -97.05000)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: NO 19 1975
DESIGNATION: 877 5270 TIDAL 19
MONUMENTATION: Tidal Station disk VM#: 11201
AGENCY: National Ocean Survey (NOS) IDB PID#: AH0184
SETTING CLASSIFICATION: Concrete manhole OPUS PID#: AH0184
LATITUDE: 27° 50.0' N ( 27.83330) LONGITUDE: 97° 3.4' W ( -97.05670)
The bench mark is a disk set flush in a concrete manhole on the north side Beach
Street, 800 m (2624.6) west of the fishing pier, and 6.1 m (20 ft) north of the
centerline of Beach Street.
BENCH MARK STAMPING: NO 20 1975
DESIGNATION: 877 5270 TIDAL 20
MONUMENTATION: Tidal Station disk VM#: 11202
AGENCY: National Ocean Survey (NOS) IDB PID#: AH0182
SETTING CLASSIFICATION: Concrete step OPUS PID:
LATITUDE: 27° 50.0' N ( 27.83330) LONGITUDE: 97° 3.6' W ( -97.06000)
The bench mark is a disk set on the first concrete step leading to Custard's
Last Stand Restaurant at the intersection of Beach Street and Station Street,
20.24 m (66.4 ft) south of Beach Street, and 9.63 m (31.6 ft) west of the
centerline of Station Street.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 6 of 8
Station ID: 8775270 PUBLICATION DATE: 06/02/2003
Name: PORT ARANSAS, H. CALDWELL PIER
TX
NOAA Chart: 11307 Latitude: 27° 49.6' N ( 27.82670)
USGS Quad: PORT ARANSAS Longitude: 97° 3.0' W ( -97.05000)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 30 + 00
DESIGNATION: 877 5270 30+00
MONUMENTATION: Survey disk VM#: 11203
AGENCY: US Army Corps of Engineers (USE) IDB PID#: AH0188
SETTING CLASSIFICATION: Concrete monument OPUS PID:
LATITUDE: 27° 49.8' N ( 27.83000) LONGITUDE: 97° 3.3' W ( -97.05500)
The bench mark is a disk set in the top of a concrete monument at the
intersection of Beach Street and a paved road leading ENE, about 82.30 m (270.0
ft) NE of bench mark NO 11 1960, 71.32 m (234.0 ft) NW of the paved road, 67.28
m (224.0 ft) NE of the centerline of Beach Street, 1.22 m (4.0 ft) south of a
witness post, and level with the ground.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 7 of 8
Station ID: 8775270 PUBLICATION DATE: 06/02/2003
Name: PORT ARANSAS, H. CALDWELL PIER
TX
NOAA Chart: 11307 Latitude: 27° 49.6' N ( 27.82670)
USGS Quad: PORT ARANSAS Longitude: 97° 3.0' W ( -97.05000)
T I D A L D A T U M S
Tidal datums at PORT ARANSAS, H. CALDWELL PIER based on:
LENGTH OF SERIES: 5 MONTHS
TIME PERIOD: March 1980 - July 1980
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:
MEAN HIGHER HIGH WATER MHHW = 0.499
MEAN HIGH WATER MHW = 0.464
MEAN SEA LEVEL MSL = 0.282
MEAN TIDE LEVEL MTL = 0.267
North American Vertical Datum NAVD88 = 0.160
MEAN LOW WATER MLW = 0.069
MEAN LOWER LOW WATER MLLW = 0.000
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
NO 11 1960 3.141 2.677
NO 12 1960 2.416 1.952
NO 13 1960 2.074 1.610
NO 15 1975 2.403 1.939
NO 16 1975 3.330 2.866
NO 17 1975 3.327 2.863
NO 18 1975 3.060 2.596
NO 19 1975 2.641 2.177
NO 20 1975 3.187 2.723
30 + 00 2.638 2.174
Foot Notes:
Bench marks NO 12 1960, NO 13 1960, NO 15 1975, NO 18 1975, NO 19 1975, and NO
20 1975 are based on one differential leveling connection and do not meet the
quality control standards of the NOS. Therefore, caution should be used when
deriving elevations for these marks.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 8 of 8
Station ID: 8775270 PUBLICATION DATE: 06/02/2003
Name: PORT ARANSAS, H. CALDWELL PIER
TX
NOAA Chart: 11307 Latitude: 27° 49.6' N ( 27.82670)
USGS Quad: PORT ARANSAS Longitude: 97° 3.0' W ( -97.05000)
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.