U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
Datums Page                                                        Page  1 of  5

                                                                                
Station ID: 8770777                         PUBLICATION DATE:  10/04/2017
Name:       MANCHESTER, HOUSTON SHIP CHANNEL                  
            TX
NOAA Chart: 11329                           Latitude:   29° 43.6' N (  29.72622)
USGS Quad:  PARK PLACE                      Longitude:  95° 15.9' W ( -95.26578)


From the junction of Interstate 10 and the I-610 loop on the east side of
Houston, proceed south on the I-610 loop to Exit 29 (Port of Houston), take Exit
29 and go for 0.7 km (0.4 mi), turn right and head west for 0.2 km (0.1 mi) to
the main gate, turn left at the gate 8 access point, once through the security
gate turn left and travel east on lower level road for 0.5 km (0.31 mi). The
tide station is south of Lower Level Road, 55.9 meters east of the 610 Bridge,
along the ship channel. The benchmarks are located along Lower Level Road and
across the chain link fence that surrounds the parking lot above the road.


                         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:           Bench Mark disk                       VM#:        15895
AGENCY:                  Lamar University Beaumont (LUB)       IDB PID#:        
SETTING CLASSIFICATION:  Stainless steel rod                   OPUS PID:        
LATITUDE:   29° 43.6' N (  29.72669)          LONGITUDE:  95° 16.1' W ( -95.26753)


The primary bench mark is a brass disk located 4.33 m (14.2 ft) NNE of the north
side of a road along Wharf 31, 3.66 m (12.0 ft) NW of a fire hydrant , 2.74 m
(9.0 ft) SSW of the south edge of railroad tracks, and 0.79 m (2.6 ft) SE of a
wood utility pole. The bench mark set 2 cm (0.8 in) below ground, crimped to a
stainless steel rod driven 16.76 m (55.0 ft) to refusal, and encased in a 6-inch
PVC pipe with a concrete kickblock.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  2 of  5

                                                                                
Station ID: 8770777                         PUBLICATION DATE:  10/04/2017
Name:       MANCHESTER, HOUSTON SHIP CHANNEL                  
            TX
NOAA Chart: 11329                           Latitude:   29° 43.6' N (  29.72622)
USGS Quad:  PARK PLACE                      Longitude:  95° 15.9' W ( -95.26578)


                         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:           Bench Mark disk                       VM#:        15897
AGENCY:                  Lamar University Beaumont (LUB)       IDB PID#:        
SETTING CLASSIFICATION:  Stainless steel rod                   OPUS PID#: DO9988
LATITUDE:   29° 43.6' N (  29.72711)          LONGITUDE:  95° 16.1' W ( -95.26781)


The bench mark is a brass survey disk located 60.29 m (197.8 ft) west of a wood
utility pole, 59.13 m (194.0 ft) west of LUB 0777 B 1995, 46.88 m (153.8 ft)
east of a wood utility pole, 45.9 m (150.6 ft) east of LUB 0777 D 1995, and 34.5
m (113.2 ft) north of the railroad tracks.  The bench mark is recessed 15 cm
(0.5 ft) below the ground, crimped to the top of a stainless steel rod driven
16.76 m (55.0 ft) to refusal, and encased in a 6-inch PVC pipe with a concrete
kickblock.



                         BENCH MARK STAMPING:  LUB 0777 D 1995
                         DESIGNATION:          877 0777 D

MONUMENTATION:           Bench Mark disk                       VM#:        15898
AGENCY:                  Lamar University Beaumont (LUB)       IDB PID#:        
SETTING CLASSIFICATION:  Stainless steel rod                   OPUS PID#: BBDQ12
LATITUDE:   29° 43.6' N (  29.72714)          LONGITUDE:  95° 16.1' W ( -95.26828)


The bench mark is a brass survey disk set in the vicinity of warehouse no. 31,
located 45.9 m (150.6 ft) west of BM 0777 C 1995, 42.6 m (139.8 ft) south of a
chainlink fence corner post, and 1.5 m (4.9 ft) NE of a power pole. The bench
mark is a recessed about 15 cm (0.5 ft) below the ground, crimped to the top of
a stainless steel rod driven 16.76 m (55.0 ft) to refusal, and encased in a
6-inch PVC pipe with a concrete kickblock.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  3 of  5

                                                                                
Station ID: 8770777                         PUBLICATION DATE:  10/04/2017
Name:       MANCHESTER, HOUSTON SHIP CHANNEL                  
            TX
NOAA Chart: 11329                           Latitude:   29° 43.6' N (  29.72622)
USGS Quad:  PARK PLACE                      Longitude:  95° 15.9' W ( -95.26578)


                         T I D A L   B E N C H   M A R K S


                         BENCH MARK STAMPING:  0777 F 2002
                         DESIGNATION:          877 0777 F TIDAL

MONUMENTATION:           Bench Mark disk                       VM#:        16912
AGENCY:                  Conrad Blucher Institute (CBI)        IDB PID#:        
SETTING CLASSIFICATION:  Sidewalk                              OPUS PID:        
LATITUDE:   29° 43.6' N (  29.72619)          LONGITUDE:  95° 16.0' W ( -95.26619)


The bench mark is a disk located 109.2 m (358.3 ft) SE of bench mark 877 0777 A,
65.5 m (214.9 ft) ESE of the NE corner of the warehouse building at Wharf 31,
and 3.00 m (9.8 ft) NE of a concrete bridge support. The bench mark is set flush
in a concrete sidewalk.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  4 of  5

                                                                                
Station ID: 8770777                         PUBLICATION DATE:  10/04/2017
Name:       MANCHESTER, HOUSTON SHIP CHANNEL                  
            TX
NOAA Chart: 11329                           Latitude:   29° 43.6' N (  29.72622)
USGS Quad:  PARK PLACE                      Longitude:  95° 15.9' W ( -95.26578)


                            T I D A L   D A T U M S 


Tidal datums at MANCHESTER, HOUSTON SHIP CHANNEL based on:

     LENGTH OF SERIES:      6 YEARS
     TIME PERIOD:           Jan 1998 - Dec 2002 & Jan 2016 - Dec 2016
     TIDAL EPOCH:           1983-2001
     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 (08/29/2017)         =  3.680
     MEAN HIGHER HIGH WATER                     MHHW   =  0.495
     MEAN HIGH WATER                            MHW    =  0.458
     MEAN SEA LEVEL                             MSL    =  0.269
     MEAN TIDE LEVEL                            MTL    =  0.266
     MEAN LOW WATER                             MLW    =  0.074
     MEAN LOWER LOW WATER                       MLLW   =  0.000
     LOWEST  OBSERVED WATER LEVEL (03/09/1998)         = -0.986

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MLLW        MHW

     LUB 0777 A 1995                             3.064    2.606
     LUB 0777 C 1995                             8.879    8.421
     LUB 0777 D 1995                             9.017    8.559
     0777 F 2002                                 4.371    3.913


                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  5 of  5

                                                                                
Station ID: 8770777                         PUBLICATION DATE:  10/04/2017
Name:       MANCHESTER, HOUSTON SHIP CHANNEL                  
            TX
NOAA Chart: 11329                           Latitude:   29° 43.6' N (  29.72622)
USGS Quad:  PARK PLACE                      Longitude:  95° 15.9' W ( -95.26578)


                             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.