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National Ocean Service
Datums Page Page 1 of 11
Station ID: 8774770 PUBLICATION DATE: 05/05/2011
Name: ROCKPORT, ARANSAS BAY
TX
NOAA Chart: 11313 Latitude: 28° 1.3' N ( 28.02167)
USGS Quad: ROCKPORT Longitude: 97° 2.8' W ( -97.04667)
To reach the bench marks from the intersection of Business State Highway 35
(Broadway) and State Highway 35, proceed south on Broadway for 0.3 km (0.2 mi)
to the junction of Broadway and Concho Streets. Turn left heading east on
Concho Street. Follow this road to the right around Rockport Yacht Basin for
0.40 km (0.25 mi) to the Texas Parks and Wildlife Marine Laboratory. The bench
marks are near the Yacht Basin. The tide gauge is on the southern-most pier in
the Yacht Basin.
T I D A L B E N C H M A R K S
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 11
Station ID: 8774770 PUBLICATION DATE: 05/05/2011
Name: ROCKPORT, ARANSAS BAY
TX
NOAA Chart: 11313 Latitude: 28° 1.3' N ( 28.02167)
USGS Quad: ROCKPORT Longitude: 97° 2.8' W ( -97.04667)
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 8 1948
DESIGNATION: 877 4770 TIDAL 8
ALIAS: NO. 8 1948
MONUMENTATION: Tidal Station disk VM#: 878
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#: AN1877
SETTING CLASSIFICATION: Concrete foundation OPUS PID#: AN1877
LATITUDE: 28° 1.6' N ( 28.02608) LONGITUDE: 97° 2.9' W ( -97.04778)
The primary bench mark is a disk set in the top of the concrete foundation of an
abandoned lamp post at the NE side of the Rockport Yacht Basin, 37.00 m (121.4
ft) east of the Yacht Basin sea wall, 23.00 m (75.5 ft) west of the third power
line pole from Aransas Bay, and 4.00 m (13.1 ft) east of the fourth power line
pole from the NE corner of the basin.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 11
Station ID: 8774770 PUBLICATION DATE: 05/05/2011
Name: ROCKPORT, ARANSAS BAY
TX
NOAA Chart: 11313 Latitude: 28° 1.3' N ( 28.02167)
USGS Quad: ROCKPORT Longitude: 97° 2.8' W ( -97.04667)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: NO 3 1934
DESIGNATION: 877 4770 TIDAL 3
ALIAS: NO 3 1934
MONUMENTATION: Tidal Station disk VM#: 874
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#: AN1401
SETTING CLASSIFICATION: Concrete sidewalk OPUS PID:
LATITUDE: 28° 1.4' N ( 28.02328) LONGITUDE: 97° 3.0' W ( -97.05072)
The bench mark is a disk set in the sidewalk at the junction of North Street and
Highway 35 (Business), 32.00 m (105.0 ft) north of the centerline of North
Street, 10.00 m (32.8 ft) west of the centerline of the southbound lane of
Highway 35, 4.00 m (13.1 ft) west of the curb of Highway 35, 1.00 m (3.3 ft)
south of the NE corner of the L.M. Bracht Building, and about 0.30 m (0.98 ft)
above the level of the highway.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 11
Station ID: 8774770 PUBLICATION DATE: 05/05/2011
Name: ROCKPORT, ARANSAS BAY
TX
NOAA Chart: 11313 Latitude: 28° 1.3' N ( 28.02167)
USGS Quad: ROCKPORT Longitude: 97° 2.8' W ( -97.04667)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: NO 4 1948
DESIGNATION: 877 4770 TIDAL 4
ALIAS: NO. 4 1948
MONUMENTATION: Bench Mark disk VM#: 875
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#: AN1880
SETTING CLASSIFICATION: Concrete bulkhead OPUS PID:
LATITUDE: 28° 1.5' N ( 28.02436) LONGITUDE: 97° 2.9' W ( -97.04786)
The bench mark is a disk set flush in the top of the concrete seawall on the
east shore of the Rockport Yacht Basin and near the SE end of the seawall, 10.61
m (34.81 ft) north of the north edge of the pier leading to the gage house, 7.32
m (24.02 ft) west of the west end of the Texas Parks and Wild Life Marine
Laboratory Building, and 0.30 m (0.98 ft) south of a chain link fence with a
gate.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 11
Station ID: 8774770 PUBLICATION DATE: 05/05/2011
Name: ROCKPORT, ARANSAS BAY
TX
NOAA Chart: 11313 Latitude: 28° 1.3' N ( 28.02167)
USGS Quad: ROCKPORT Longitude: 97° 2.8' W ( -97.04667)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: NO 11 1975
DESIGNATION: 877 4770 TIDAL 11
ALIAS: NO. 11 1975
MONUMENTATION: Tidal Station disk VM#: 880
AGENCY: National Ocean Survey (NOS) IDB PID#: AN1874
SETTING CLASSIFICATION: Retaining wall OPUS PID:
LATITUDE: 28° 1.4' N ( 28.02381) LONGITUDE: 97° 3.0' W ( -97.05053)
The bench mark is a disk set flush on top of a retaining at the east side of the
parking lot for the Western Auto Store, located on wall on the west side of
Business 35 between North St. and Navigation Cir., 15.00 m (49.2 ft) west of the
centerline of Business 35, 14.00 m (45.9 ft) north of a drive beside Western
Auto, 0.91 m (2.99 ft) south of the NE corner of the retaining wall, and about
0.49 m (1.608 ft) above the sidewalk.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 6 of 11
Station ID: 8774770 PUBLICATION DATE: 05/05/2011
Name: ROCKPORT, ARANSAS BAY
TX
NOAA Chart: 11313 Latitude: 28° 1.3' N ( 28.02167)
USGS Quad: ROCKPORT Longitude: 97° 2.8' W ( -97.04667)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING:
DESIGNATION: 877 4770 TIDAL 9 TXHD
ALIAS: NO STAMPING 1
MONUMENTATION: Tidal Station disk VM#: 882
AGENCY: Texas Highway Department IDB PID#: AN1875
SETTING CLASSIFICATION: Concrete monument OPUS PID:
LATITUDE: 28° 1.5' N ( 28.02486) LONGITUDE: 97° 3.0' W ( -97.05025)
The bench mark is a disk set in the top of a concrete post, at the NW corner of
the Rockport Yacht Basin, in the SW portion of a small city park and picnic
area, 22.19 m (72.80 ft) NW of a white flag pole, 17.71 m (58.10 ft) north of a
manhole on the east side of Highway 35, and 15.21 m (49.90 ft) east of the
centerline of Highway 35, and 0.15 m (0.49 ft) above ground level.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 7 of 11
Station ID: 8774770 PUBLICATION DATE: 05/05/2011
Name: ROCKPORT, ARANSAS BAY
TX
NOAA Chart: 11313 Latitude: 28° 1.3' N ( 28.02167)
USGS Quad: ROCKPORT Longitude: 97° 2.8' W ( -97.04667)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 4770 A 2002
DESIGNATION: 877 4770 A
ALIAS: 4770 A
MONUMENTATION: Flange-encased Rod VM#: 17287
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Stainless steel rod in sleeve OPUS PID:
LATITUDE: 28° 1.6' N ( 28.02619) LONGITUDE: 97° 2.9' W ( -97.04867)
The bench mark is a flange-encased rod located at the Rockport Yacht Basin,
27.49 m (90.2 ft) NNW of a utility pole marked "4", 22.31 m (73.2 ft) ENE of a
utility pole marked "3", 18.29 m (60.0 ft) SW of a utility pole marked "G70" in
the Chambers and Veterans Memorial/Texas Maritime Museum property, and 7.60 m
(24.93 ft) south of the southernmost corner of "Margaret Surust Foundation and
HEB" monument. The datum point is the top of a stainless steel rod driven 15.3
m (50 ft) to substantial resistance, and encased in a one meter long sleeve and
NOS logo cap. Note -The sleeve depth does not meet the specifications for a
Class A rod mark.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 8 of 11
Station ID: 8774770 PUBLICATION DATE: 05/05/2011
Name: ROCKPORT, ARANSAS BAY
TX
NOAA Chart: 11313 Latitude: 28° 1.3' N ( 28.02167)
USGS Quad: ROCKPORT Longitude: 97° 2.8' W ( -97.04667)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 4770 B 2004
DESIGNATION: 877 4770 B
ALIAS: 4770 B
MONUMENTATION: Flange-encased Rod VM#: 17807
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Stainless steel rod OPUS PID#: DN7652
LATITUDE: 28° 1.5' N ( 28.02556) LONGITUDE: 97° 3.0' W ( -97.04972)
The bench mark is a flange-encased rod located 29.9 m (98.1 ft) west of a
utility pole marked "2", 17.6 m (57.74 ft) north of the northernmost corner of
the northernmost of three concrete picnic pavillions, 12.1 m (39.7 ft) SSE of
the centerline of E Concho Street. The stainless steel rod is driven 15.8 m
(52.0 ft), encased in 6 inch pvc pipe and 0.3 m (0.98 ft) below grade with
concrete kickblock . Note: Mark is covered with grass.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 9 of 11
Station ID: 8774770 PUBLICATION DATE: 05/05/2011
Name: ROCKPORT, ARANSAS BAY
TX
NOAA Chart: 11313 Latitude: 28° 1.3' N ( 28.02167)
USGS Quad: ROCKPORT Longitude: 97° 2.8' W ( -97.04667)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 4770 C 2004
DESIGNATION: 877 4770 TIDAL C
ALIAS: 4770 C Picnic beach
MONUMENTATION: Tidal Station disk VM#: 17808
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Picnic pavillion foundation OPUS PID:
LATITUDE: 28° 1.5' N ( 28.02517) LONGITUDE: 97° 4.0' W ( -97.06667)
The bench mark is a disk set into the NE corner of the middle concrete picnic
pavillion, located 29.4 m (96.5 ft) west of a utility pole marked "1", 17.9 m
(58.7 ft) east of the easternmost curb of Broadway St., 16.7 m (54.8 ft) NNW of
the northernmost corner of a memorial granite bench marked "Rockport VFW Post
3904, May 30 1994". The mark is 0.85 m (2.79 ft) south of the northermost
corner of the middle concrete picnic pavillion. The mark is a brass NOS surface
disk.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 10 of 11
Station ID: 8774770 PUBLICATION DATE: 05/05/2011
Name: ROCKPORT, ARANSAS BAY
TX
NOAA Chart: 11313 Latitude: 28° 1.3' N ( 28.02167)
USGS Quad: ROCKPORT Longitude: 97° 2.8' W ( -97.04667)
T I D A L D A T U M S
Tidal datums at ROCKPORT, ARANSAS BAY based on:
LENGTH OF SERIES: 5 YEARS
TIME PERIOD: January 2002 - December 2006
TIDAL EPOCH: 2002-2006
CONTROL TIDE STATION:
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
HIGHEST OBSERVED WATER LEVEL (08/10/1980) = 1.249
MEAN HIGHER HIGH WATER MHHW = 0.111
MEAN HIGH WATER MHW = 0.110
MEAN SEA LEVEL MSL = 0.058
MEAN TIDE LEVEL MTL = 0.055
MEAN LOW WATER MLW = 0.001
MEAN LOWER LOW WATER MLLW = 0.000
North American Vertical Datum NAVD88 = -0.285
LOWEST OBSERVED WATER LEVEL (02/29/1984) = -0.800
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
8 1948 1.418 1.308
NO 3 1934 1.108 0.998
NO 4 1948 0.840 0.730
NO 11 1975 1.433 1.323
877 4770 TIDAL 9 TXHD 1.530 1.420
4770 A 2002 1.240 1.130
4770 B 2004 1.032 0.922
4770 C 2004 1.425 1.315
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 11 of 11
Station ID: 8774770 PUBLICATION DATE: 05/05/2011
Name: ROCKPORT, ARANSAS BAY
TX
NOAA Chart: 11313 Latitude: 28° 1.3' N ( 28.02167)
USGS Quad: ROCKPORT Longitude: 97° 2.8' W ( -97.04667)
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.