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National Ocean Service
Datums Page Page 1 of 10
Station ID: 8779770 PUBLICATION DATE: 02/09/2009
Name: PORT ISABEL, LAGUNA MADRE
TX
NOAA Chart: 11301 Latitude: 26° 3.6' N ( 26.06000)
USGS Quad: PORT ISABEL Longitude: 97° 12.9' W ( -97.21500)
To reach the tidal bench marks from the old lighthouse at Port Isabel, proceed
west on State Highway 100 for 1.4 km (0.9 mi) to a road leading to Port Isabel
Turning Basin. Turn left onto the road and continue south for 1.1 km (0.7 mi)
to the Port Isabel Navigation District warehouse. The bench marks are in the
vicinity of the warehouse, Port Road, and the Port Isabel High School complex.
The tide gage and staff are approximately 24.4 m (80 ft) north of the NE corner
of the warehouse.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: NO 10 1973
DESIGNATION: 877 9770 TIDAL 10
MONUMENTATION: Tidal Station disk VM#: 901
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#: AB1227
SETTING CLASSIFICATION: Concrete head wall OPUS PID:
LATITUDE: 26° 3.8' N ( 26.06250) LONGITUDE: 97° 12.9' W ( -97.21500)
The primary bench mark is a disk set flush in the top of the north end of a
concrete headwall of a large culvert under Port Road on the east side of the
road leading to the warehouse, 28.50 m (93.5 ft) SE of a power pole with a
light, 22.31 m (73.2 ft) SSE of 2 oil pipe line valves, 8.81 m (28.9 ft) east of
the centerline of the road, 6.71 m (22.0 ft) north of the south end of the
concrete headwall, and 0.24 m (0.8 ft) south of the north end of the headwall.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 10
Station ID: 8779770 PUBLICATION DATE: 02/09/2009
Name: PORT ISABEL, LAGUNA MADRE
TX
NOAA Chart: 11301 Latitude: 26° 3.6' N ( 26.06000)
USGS Quad: PORT ISABEL Longitude: 97° 12.9' W ( -97.21500)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: NO 12 1972
DESIGNATION: 877 9770 TIDAL 12
MONUMENTATION: Survey disk VM#: 899
AGENCY: National Ocean Survey (NOS) IDB PID#: AB1224
SETTING CLASSIFICATION: Concrete footing OPUS PID:
LATITUDE: 26° 3.7' N ( 26.06139) LONGITUDE: 97° 12.8' W ( -97.21361)
The bench mark is a disk set in the SW corner of the concrete base of the SE leg
of the Port Isabel water tower located in the vicinity of the Port Isabel High
School complex, about 45.68 m (149.9 ft) NE of the center of Port Road, 13.50 m
(44.3 ft) east of the east wall of the building housing District No. 1 Office of
Cameron County Fresh Water Supply Tower, and 2.60 m (8.5 ft) north of the south
quarter of a rectangular cyclone fence around the tower.
BENCH MARK STAMPING: NO 13 1972
DESIGNATION: 877 9770 TIDAL 13
MONUMENTATION: Tidal Station disk VM#: 900
AGENCY: National Ocean Survey (NOS) IDB PID#: AB1226
SETTING CLASSIFICATION: Concrete sea wall OPUS PID:
LATITUDE: 26° 3.8' N ( 26.06333) LONGITUDE: 97° 12.8' W ( -97.21386)
The bench mark is a disk set in the top of a concrete seawall at the Shrimp Boat
Piers north of the Turning Basin, located on the seawall in the SE corner of the
body of water at the Shrimp Boat Piers, 91.41 m (299.9 ft) north and across the
road from the old oil dock, 21.31 m (69.9 ft) WNW of a power pole with a guy
wire, 19.80 m (64.96 ft) north of the center of the paved road, 6.80 m (22.3 ft)
south of a light pole, 0.7 m (2.3 ft) east of the east edge of the pier, and
0.55 m (1.8 ft) south of the north end of the seawall.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 10
Station ID: 8779770 PUBLICATION DATE: 02/09/2009
Name: PORT ISABEL, LAGUNA MADRE
TX
NOAA Chart: 11301 Latitude: 26° 3.6' N ( 26.06000)
USGS Quad: PORT ISABEL Longitude: 97° 12.9' W ( -97.21500)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: X 1406 1982
DESIGNATION: X 1406
MONUMENTATION: Flange-encased Rod VM#: 902
AGENCY: National Ocean Survey (NOS) IDB PID#: AB1225
SETTING CLASSIFICATION: Stainless steel rod in sleeve OPUS PID#: AB1225
LATITUDE: 26° 3.8' N ( 26.06311) LONGITUDE: 97° 12.8' W ( -97.21386)
The bench mark is a flange-encased rod located in the vicinity of the abandoned
Port Isabel oil dock, 36.58 m (120.0 ft) south of bench mark NO 13 1972, 13.29 m
(43.6 ft) south of the centerline of the paved road, 12.95 m (42.5 ft) west of a
power pole with a meter box, and 1 m (3.3 ft) SSW of power pole #34. The datum
point is the top of a stainless steel rod driven 14.6 m (48 ft), and encased in
a sleeve and NGS logo cap.
BENCH MARK STAMPING: 9
DESIGNATION: 9 USE
MONUMENTATION: Survey disk VM#: 903
AGENCY: US Army Corps of Engineers (USE) IDB PID#: AB0245
SETTING CLASSIFICATION: Concrete monument OPUS PID:
LATITUDE: 26° 3.8' N ( 26.06306) LONGITUDE: 97° 13.0' W ( -97.21611)
The bench mark is a disk set in the top of a concrete monument at the Port
Isabel turning basin, approximately halfway between the water tower and the
abandoned oil dock, 83.80 m (274.9 ft) east of the centerline of Port Road,
45.38 m (148.9 ft) south of the centerline of a dirt road running east and west,
9.4 m (30.8 ft) east of a witness post, 8.81 m (28.9 ft) east of the east corner
of a small earth oil reservoir, and 0.18 m (0.6 ft) above the ground.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 10
Station ID: 8779770 PUBLICATION DATE: 02/09/2009
Name: PORT ISABEL, LAGUNA MADRE
TX
NOAA Chart: 11301 Latitude: 26° 3.6' N ( 26.06000)
USGS Quad: PORT ISABEL Longitude: 97° 12.9' W ( -97.21500)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 9770 A 1998
DESIGNATION: 877 9770 A
MONUMENTATION: Flange-encased Rod VM#: 16203
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Stainless steel rod OPUS PID:
LATITUDE: 26° 3.7' N ( 26.06089) LONGITUDE: 97° 13.0' W ( -97.21589)
The bench mark is a flange-encased rod located within the chainlink fence area
for the San Benito Navigation District Cargo dock between the concrete drive and
the chainlink fence, 25.70 m (84.3 ft) SW (215 magnetic) of the southwestern
bell telephone junction box number 1000, 19.40 m (63.7 ft) SE (143 magnetic) of
the NW corner of the chainlink fence enclosure, 10.00 m (32.8 ft) ENE (60
magnetic) of the SE corner of the north concrete ramp footing of a truck scale,
and 0.35 m (1.15 ft) NE (53 magnetic) of the chainlink fence. The datum point
is set 8 cm (0.3 ft) below the ground, being the top of a stainless seel rod
driven 16.2 m (53 ft) to refusal, and encased in a 5-inch PVC pipe with a 5-inch
NOS logo cap and a concrete kickblock. 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 5 of 10
Station ID: 8779770 PUBLICATION DATE: 02/09/2009
Name: PORT ISABEL, LAGUNA MADRE
TX
NOAA Chart: 11301 Latitude: 26° 3.6' N ( 26.06000)
USGS Quad: PORT ISABEL Longitude: 97° 12.9' W ( -97.21500)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 9770 B 1998
DESIGNATION: 877 9770 B
MONUMENTATION: Flange-encased Rod VM#: 16204
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Stainless steel rod OPUS PID#: DP0740
LATITUDE: 26° 3.7' N ( 26.06139) LONGITUDE: 97° 12.9' W ( -97.21556)
The bench mark is a flange-encased rod located west of Port Road, 100 m (328.1
ft) north of the chainlink fence area for the San Benito Navigation District
Cargo dock, 27.70 m (90.9 ft) NNW (330 magnetic) of the wooden light pole number
A7096, 21.40 m (70.2 ft) WSW (246 magnetic) of the centerline of Port Road,
10.90 m (35.8 ft) WNW (300 magnetic) of the centerline of a paved drive to a
parking area for Texas Pack, and 2.85 m (9.4 ft) ENE (65 magnetic) of the wooden
fence post at the SE corner of the Amareda Hess property. The datum point is set
8 cm (0.26 ft) below the ground, being the top of a stainless steel rod driven
17.7 m (58 ft) to refusal, and encased in a 5-inch PVC pipe with a 5-inch NOS
logo cap and a concrete kickblock. 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 6 of 10
Station ID: 8779770 PUBLICATION DATE: 02/09/2009
Name: PORT ISABEL, LAGUNA MADRE
TX
NOAA Chart: 11301 Latitude: 26° 3.6' N ( 26.06000)
USGS Quad: PORT ISABEL Longitude: 97° 12.9' W ( -97.21500)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 9770 C 2002
DESIGNATION: 877 9770 C
MONUMENTATION: Flange-encased Rod VM#: 17322
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Stainlless steel rod OPUS PID:
LATITUDE: 26° 3.7' N ( 26.06139) LONGITUDE: 97° 12.9' W ( -97.21556)
The benchmark is a flange-encased rod is 13.7 m (44.9 ft) west (260 degrees) of
the centerline of asphalt road leading to tide station, and 0.8 m (2.6 ft) east
(80 degrees) of utility pole marked "A 6656". The datum point is set being the
top of a stainless steel rod driven 10.7 m (35 ft) to refusal, encased in a
6-inch pvc pipe with a concrete kick block. Note-sleeve depth does not meet the
specifications of a class A rod mark.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 7 of 10
Station ID: 8779770 PUBLICATION DATE: 02/09/2009
Name: PORT ISABEL, LAGUNA MADRE
TX
NOAA Chart: 11301 Latitude: 26° 3.6' N ( 26.06000)
USGS Quad: PORT ISABEL Longitude: 97° 12.9' W ( -97.21500)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 9770 D 2002
DESIGNATION: 877 9770 D
MONUMENTATION: Flange-encased Rod VM#: 17323
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Stainless steel rod OPUS PID:
LATITUDE: 26° 3.7' N ( 26.06139) LONGITUDE: 97° 12.9' W ( -97.21556)
The bench mark is a flange-encased rod located on the west side of Port Road,
13.8 m (45.3 ft) west (260 degrees) of centerline of same road, and 0.85 m (2.79
ft) east (80 degrees) of a utility pole with 3 transformers on top and across
the street from Frankies Bait Stand. The datum point is set being the top of a
stainless steel rod driven 12.1 m (39 ft) to refusal, encased in a 6-inch PVC
pipe with a metal cap and concrete kick block. . Note: Sleeve depth does not
meet the specifications of a class A rod mark. The benchmark is a stainless
steel rod driven soft to refusal in a concrete kickblock with 6" PVC pipe with a
metal cap. The mark is 0.85 m (2.79 ft) east (80 degreees) of a utility pole
with 3 transformers on top and across the street from Frankies bait stand and
13.8 m (45.3 ft) west (260 degrees) of centerline of same road.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 8 of 10
Station ID: 8779770 PUBLICATION DATE: 02/09/2009
Name: PORT ISABEL, LAGUNA MADRE
TX
NOAA Chart: 11301 Latitude: 26° 3.6' N ( 26.06000)
USGS Quad: PORT ISABEL Longitude: 97° 12.9' W ( -97.21500)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 9770 F 2002
DESIGNATION: 877 9770 F
MONUMENTATION: Flange-encased Rod VM#: 17324
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Stainless steel rod OPUS PID:
LATITUDE: 26° 3.7' N ( 26.06139) LONGITUDE: 97° 12.9' W ( -97.21556)
The bench mark is a flange-encased rod located 25.90 m (85 ft) south of the
north entrance to the boys and girls club in Port Isabel Texas, 13.80 m (45.3
ft) NW of the centerline of entrance road, 245 degrees west of the centerline of
Port Road, and approximately 0.61 m (2 ft) east of light pole T2973. The datum
point is set being the top of a stainless steel rod driven to an unspecified
depth of refusal.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 9 of 10
Station ID: 8779770 PUBLICATION DATE: 02/09/2009
Name: PORT ISABEL, LAGUNA MADRE
TX
NOAA Chart: 11301 Latitude: 26° 3.6' N ( 26.06000)
USGS Quad: PORT ISABEL Longitude: 97° 12.9' W ( -97.21500)
T I D A L D A T U M S
Tidal datums at PORT ISABEL, LAGUNA MADRE based on:
LENGTH OF SERIES: 19 YEARS
TIME PERIOD: January 1983 - December 2001
TIDAL EPOCH: 1983-2001
CONTROL TIDE STATION:
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
HIGHEST OBSERVED WATER LEVEL (08/09/1980) = 2.147
MEAN HIGHER HIGH WATER MHHW = 0.418
MEAN HIGH WATER MHW = 0.400
North American Vertical Datum NAVD88 = 0.260
MEAN SEA LEVEL MSL = 0.247
MEAN TIDE LEVEL MTL = 0.224
MEAN LOW WATER MLW = 0.049
MEAN LOWER LOW WATER MLLW = 0.000
LOWEST OBSERVED WATER LEVEL (12/13/1989) = -0.660
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
NO 10 1973 3.101 2.700
NO 12 1972 5.618 5.218
NO 13 1972 1.370 0.970
X 1406 1982 1.616 1.216
9 0.893 0.493
9770 A 1998 3.229 2.829
9770 B 1998 2.823 2.423
9770 C 2002 2.514 2.114
9770 D 2002 2.655 2.255
9770 F 2002 3.390 2.990
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 10 of 10
Station ID: 8779770 PUBLICATION DATE: 02/09/2009
Name: PORT ISABEL, LAGUNA MADRE
TX
NOAA Chart: 11301 Latitude: 26° 3.6' N ( 26.06000)
USGS Quad: PORT ISABEL Longitude: 97° 12.9' W ( -97.21500)
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.