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Bench Mark Sheet for 8770625, UMBRELLA POINT, TRINITY BAY TX

Superseded Epoch

Large map location marker Station Location
Small red map location marker Published bench mark
Small blue map location marker Unpublished bench mark

Bench mark positions only appear on the map if their coordinates in the CO-OPS database are at the precision of degrees/minutes/seconds/and tenths of seconds. If the coordinates are less precise, the mark will not appear.

Printable version

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

                                                                                
Station ID: 8770625                         PUBLICATION DATE:  07/26/2011
Name:       UMBRELLA POINT, TRINITY BAY                       
            TX
NOAA Chart: 11327                           Latitude:   29° 40.8' N (  29.68000)
USGS Quad:  UMBRELLA POINT                  Longitude:  94° 52.1' W ( -94.86833)


To reach the tidal bench marks from Texas Hwy. 146 south of Baytown, proceed 4.3
km (2.7 mi) east on Spur 55 (Fisher Dr.) to FM 1405, south on FM 1405 9.5 km
(5.9 mi) to its end at FM 2354 and 5.6 km (3.5  mi) on North FM 2354 to
Crawley's Fishing Camp.  The bench marks are located in and around the parking
area which is 0.3 km (0.2 mi) from the road at the end of the dirt driveway.


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


                 PRIMARY BENCH MARK STAMPING:  0625A 1994
                         DESIGNATION:          877 0625 A

MONUMENTATION:           Survey disk                           VM#:        16466
AGENCY:                  National Ocean Service (NOS)          IDB PID#:        
SETTING CLASSIFICATION:  Concrete slab                         OPUS PID:        
LATITUDE:   29° 40.8' N (  29.68000)          LONGITUDE:  94° 52.1' W ( -94.86830)


The primary bench mark is a disk set flush in a concrete slab 13.72 m (45.0 ft)
NW of the western end of the southern breakwater which encloses the boat basin,
11.28 m (37.0 ft) west of the seaward corner of the wall which extends along the
southern-most boat ramp and 28.65 m (94.0 ft) south  of Bench Mark 0625B 1994.

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

                                                                                
Station ID: 8770625                         PUBLICATION DATE:  07/26/2011
Name:       UMBRELLA POINT, TRINITY BAY                       
            TX
NOAA Chart: 11327                           Latitude:   29° 40.8' N (  29.68000)
USGS Quad:  UMBRELLA POINT                  Longitude:  94° 52.1' W ( -94.86833)


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


                         BENCH MARK STAMPING:  0625B 1994
                         DESIGNATION:          877 0625 B

MONUMENTATION:           Survey disk                           VM#:        16467
AGENCY:                  National Ocean Service (NOS)          IDB PID#:        
SETTING CLASSIFICATION:  Boat ramp                             OPUS PID:        
LATITUDE:   29° 40.8' N (  29.68000)          LONGITUDE:  94° 52.1' W ( -94.86830)


The bench mark is a disk set flush in the west end of the northern-most boat
ramp in the Crawly boat basin, 1.22 m (4.0 ft) south of the northern wall which
extends along the boat ramp, 7.32 m (24.0 ft) east of the SE corner of the bait
shed, and 21 m (69 ft) west of the eastern-most piling of the pier which extends
east from the bait shed.



                         BENCH MARK STAMPING:  0625D 1994
                         DESIGNATION:          877 0625 D

MONUMENTATION:           Survey disk                           VM#:        16469
AGENCY:                  National Ocean Service (NOS)          IDB PID#:        
SETTING CLASSIFICATION:  Concrete slab                         OPUS PID:        
LATITUDE:   29° 40.8' N (  29.68000)          LONGITUDE:  94° 52.1' W ( -94.86830)


The bench mark is a disk set flush in a concrete slab 1.22 m (4.0 ft) south of
the south side of the fish cleaning shed, 1.83 m (6.0 ft) SW of the SE corner of
the fish cleaning shed, 13.72 m (45.0 ft) SE of the mechanical boat lift ruins,
and 8.23 m (27.0 ft) west of the SW corner of a small aluminum building next to
the bait shed.

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

                                                                                
Station ID: 8770625                         PUBLICATION DATE:  07/26/2011
Name:       UMBRELLA POINT, TRINITY BAY                       
            TX
NOAA Chart: 11327                           Latitude:   29° 40.8' N (  29.68000)
USGS Quad:  UMBRELLA POINT                  Longitude:  94° 52.1' W ( -94.86833)


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


                         BENCH MARK STAMPING:  0625E 1994
                         DESIGNATION:          877 0625 E

MONUMENTATION:           Survey disk                           VM#:        16470
AGENCY:                  National Ocean Service (NOS)          IDB PID#:        
SETTING CLASSIFICATION:  Concrete sea wall                     OPUS PID:        
LATITUDE:   29° 40.8' N (  29.68000)          LONGITUDE:  94° 52.1' W ( -94.86830)


Bench mark is a disk set flush in the top of a concrete seawall 15.85 m (52.0
ft) north of the north end of the slab surrounding the boat lift ruins, 41.45 m
(136.0 ft) NNW of Bench Mark 0625D 1994, and 9.45 m (31.0 ft) south of the
northern corner of the sea wall.

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

                                                                                
Station ID: 8770625                         PUBLICATION DATE:  07/26/2011
Name:       UMBRELLA POINT, TRINITY BAY                       
            TX
NOAA Chart: 11327                           Latitude:   29° 40.8' N (  29.68000)
USGS Quad:  UMBRELLA POINT                  Longitude:  94° 52.1' W ( -94.86833)


                            T I D A L   D A T U M S 


Tidal datums at UMBRELLA POINT, TRINITY BAY based on:

     LENGTH OF SERIES:      9 MONTHS
     TIME PERIOD:           September 1995 - May 1996
     TIDAL EPOCH:           1983-2001
     CONTROL TIDE STATION:  8771450 GALVESTON PIER 21, GALVESTON CHANNEL


Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:

     MEAN HIGHER HIGH WATER                     MHHW   =  0.388
     MEAN HIGH WATER                            MHW    =  0.376
     MEAN SEA LEVEL                             MSL    =  0.212
     MEAN TIDE LEVEL                            MTL    =  0.203
     MEAN LOW WATER                             MLW    =  0.029
     MEAN LOWER LOW WATER                       MLLW   =  0.000

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MLLW        MHW

     0625A 1994                                  1.067    0.691
     0625B 1994                                  0.799    0.423
     0625D 1994                                  1.186    0.810
     0625E 1994                                  0.834    0.458


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

                                                                                
Station ID: 8770625                         PUBLICATION DATE:  07/26/2011
Name:       UMBRELLA POINT, TRINITY BAY                       
            TX
NOAA Chart: 11327                           Latitude:   29° 40.8' N (  29.68000)
USGS Quad:  UMBRELLA POINT                  Longitude:  94° 52.1' W ( -94.86833)


                             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.

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Products available at 8770625 UMBRELLA POINT, TRINITY BAY, TX

Revised: 08/08/2018
NOAA / National Ocean Service
Web site owner: Center for Operational Oceanographic Products and Services