U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 6
PUBLICATION DATE: 08/07/2000
Station ID: 8770777 SUPERCEDED DATE: 04/21/2003
Name: MANCHESTER, HOUSTON SHIP CHANNEL
TEXAS
NOAA Chart: 11329 Latitude: 29° 43.0' N
USGS Quad: PARK PLACE Longitude: 95° 16.0' W
To reach the tidal bench marks from the intersection of Interstate Loop 610 and
Texas Highway 225 in east Houston, proceed north on Loop 610 for 2.4 km (1.5 mi)
over the Houston Ship Channel and take the first exit, follow along the frontage
road for 0.3 km (0.2 km), cross over the Loop and continue south on the frontage
road for 0.8 km (0.5 mi) to the Port of Houston Authority entrance gate on the
right, go through the checkpoint booth for 0.3 km (0.2 mi) to the traffic light,
turn left and continue 0.3 km (0.2 mi) to a stop sign, turn left and continue
0.5 km (0.3 mi) to the bulkhead along the channel. The bench marks are located
along the bulkhead and in the vicinity of warehouse No. 31. The tide gage was
located along the bulkhead nearly under the Loop bridge.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: LUB 0777 A 1995
DESIGNATION: 877 0777 A
MONUMENTATION: Survey disk VM#: 15895
AGENCY: Lamar University Beaumont (LUB) PID:
SETTING CLASSIFICATION: Stainless steel rod
The primary bench mark is a disk set in the vicinity of warehouse No. 31, 45.42
m (149.0 ft) north of the NE corner of its loading dock, 3.75 m (12.3 ft) north
of a fire hydrant, 3.63 m (11.9 ft) south of the centerline of a railroad track,
and 0.61 m (2.0 ft) SE of a power pole. The bench mark is crimped to a stainless
steel rod driven 13.7 m (45 ft), and encased in a 6-inch PVC pipe and concrete
kickblock.
BENCH MARK STAMPING: LUB 0777 B 1995
DESIGNATION: 877 0777 B
MONUMENTATION: Survey disk VM#: 15896
AGENCY: Lamar University Beaumont (LUB) PID:
SETTING CLASSIFICATION: Stainless steel rod
The bench mark is a disk set in the vicinity of warehouse No. 31, 46.60 m (152.9
ft) NE of bench mark LUB 0777 A 1995, 11.09 m (36.4 ft) west of a chainlink
fence, and 1.22 m (4.0 ft) north of a power pole. The bench mark is crimped to
a stainless steel rod driven 15.2 m (50 ft), and encased in a 6-inch PVC pipe
and concrete kickblock.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 6
PUBLICATION DATE: 08/07/2000
Station ID: 8770777 SUPERCEDED DATE: 04/21/2003
Name: MANCHESTER, HOUSTON SHIP CHANNEL
TEXAS
NOAA Chart: 11329 Latitude: 29° 43.0' N
USGS Quad: PARK PLACE Longitude: 95° 16.0' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: LUB 0777 C 1995
DESIGNATION: 877 0777 C
MONUMENTATION: Survey disk VM#: 15897
AGENCY: Lamar University Beaumont (LUB) PID:
SETTING CLASSIFICATION: Stainless steel rod
The bench mark is a disk set in the vicinity of warehouse No. 31, 59.34 m (194.7
ft) west of bench mark LUB 0777 B 1995, and 44.59 m (146.3 ft) south of a power
pole. The bench mark is crimped to a stainless steel rod driven 15.2 m (50 ft),
and encased in a 6-inch PVC pipe and concrete kickblock.
BENCH MARK STAMPING: LUB 0777 D 1995
DESIGNATION: 877 0777 D
MONUMENTATION: Survey disk VM#: 15898
AGENCY: Lamar University Beaumont (LUB) PID:
SETTING CLASSIFICATION: Stainless steel rod
The bench mark is a disk set in the vicinity of warehouse No. 31, 45.90 m (150.6
ft) west of bench mark LUB 0777 C 1995, 42.55 m (139.6 ft) south of a chainlink
fence corner post, and 1.52 m (5.0 ft) NE of a power pole. The bench mark is
crimped to a stainless steel rod driven 15.2 m (50 ft), and encased in a 6-inch
PVC pipe and concrete kickblock.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 6
PUBLICATION DATE: 08/07/2000
Station ID: 8770777 SUPERCEDED DATE: 04/21/2003
Name: MANCHESTER, HOUSTON SHIP CHANNEL
TEXAS
NOAA Chart: 11329 Latitude: 29° 43.0' N
USGS Quad: PARK PLACE Longitude: 95° 16.0' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: LUB 0777 E 1995
DESIGNATION: 877 0777 E
MONUMENTATION: Survey disk VM#: 15899
AGENCY: Lamar University Beaumont (LUB) PID:
SETTING CLASSIFICATION: Stainless steel rod
The bench mark is a disk set in the vicinity of warehouse No. 31, 34.99 m (114.8
ft) NW of bench mark LUB 0777 D 1995, 33.16 m (108.8 FT) SW of a power pole, and
14.17 m (46.5 ft) SW of a chainlink fence corner post. The bench mark is
crimped to a stainless steel rod driven 15.2 m (50 ft), and encased in a 6-inch
PVC pipe and concrete kickblock.
BENCH MARK STAMPING: TX DOT BM
DESIGNATION: 877 0777 TX DOT
MONUMENTATION: Survey disk VM#: 15900
AGENCY: TX DOT PID:
SETTING CLASSIFICATION: Massive retaining wall
The bench mark is a disk set in the concrete bulkhead on the north side of the
ship channel west of the I-610 loop bridge, and 7.6 m (25 ft) east of a corner
of the bulkhead.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 6
PUBLICATION DATE: 08/07/2000
Station ID: 8770777 SUPERCEDED DATE: 04/21/2003
Name: MANCHESTER, HOUSTON SHIP CHANNEL
TEXAS
NOAA Chart: 11329 Latitude: 29° 43.0' N
USGS Quad: PARK PLACE Longitude: 95° 16.0' W
T I D A L D A T U M S
Tidal datums at MANCHESTER, HOUSTON SHIP CHANNEL based on:
LENGTH OF SERIES: 1 YEAR
TIME PERIOD: January 1998 - December 1998
TIDAL EPOCH: 1960-1978
CONTROL TIDE STATION: 8770613 MORGANS POINT, BARBOURS CUT
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
HIGHEST OBSERVED WATER LEVEL (09/11/1998) = 2.371
MEAN HIGHER HIGH WATER MHHW = 0.495
MEAN HIGH WATER MHW = 0.451
MEAN SEA LEVEL MSL = 0.272
MEAN TIDE LEVEL MTL = 0.264
MEAN LOW WATER MLW = 0.078
MEAN LOWER LOW WATER MLLW = 0.000
LOWEST OBSERVED WATER LEVEL (03/09/1998) = -1.022
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
LUB 0777 A 1995 3.028 2.577
LUB 0777 B 1995 8.923 8.472
LUB 0777 C 1995 8.843 8.392
LUB 0777 D 1995 8.982 8.531
LUB 0777 E 1995 8.934 8.483
TX DOT BM 4.283 3.832
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 6
PUBLICATION DATE: 08/07/2000
Station ID: 8770777 SUPERCEDED DATE: 04/21/2003
Name: MANCHESTER, HOUSTON SHIP CHANNEL
TEXAS
NOAA Chart: 11329 Latitude: 29° 43.0' N
USGS Quad: PARK PLACE Longitude: 95° 16.0' W
Foot Notes:
Galveston Bay, Texas has anomalous relative sea level trends compared to most
other geographic regions in the United States. This is due to a general
subsidence of land in this area, which has been ocurring at a rapid rapid.
Because of the magnitude of the sea level trends in these areas, NOAA has
adopted a procedure for computing accepted tidal datums for the National Water
Level Observation Network (NWLON) using the last several years of sea level data
rather than the 19 - year tidal epoch. The tide ranges are still based on the
1960 - 1978 National Tidal Datum Epoch (NTDE) and are applied to the 5-year
(1990 - 1994) mean tide level (MTL) to compute other tidal datums. The adoption
of this procedure was necessary to ensure that these tidal datums accurately
represent the existing stand of sea level.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 6 of 6
PUBLICATION DATE: 08/07/2000
Station ID: 8770777 SUPERCEDED DATE: 04/21/2003
Name: MANCHESTER, HOUSTON SHIP CHANNEL
TEXAS
NOAA Chart: 11329 Latitude: 29° 43.0' N
USGS Quad: PARK PLACE Longitude: 95° 16.0' W
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 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.