Bench Mark Sheet for 8773259, Port Lavaca 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Superseded Epoch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Small blue map location marker Unpublished bench mark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: 8773259                         PUBLICATION DATE:  08/15/2018
Name:       PORT LAVACA, LAVACA CAUSEWAY                      
            TX
NOAA Chart: 11317                           Latitude:   28° 38.4' N (  28.64060)
USGS Quad:  CALHOUN                         Longitude:  96° 36.6' W ( -96.60980)


To reach the station from the intersection of HWY 87 and HWY 35 in Port Lavaca,
Texas, travel north on HWY 35 for 4.48 km (2.78 mi), turn right on Broadway St.
and proceed 0.14 km (0.09 mi) to the entrance of the county park. The bench
marks are located inside the park, in the vicinty of the boat ramp. The tide
station is located on the state fishing pier in Port Lavaca, Texas, 91.4 m
(299.9 ft) bayward of the public restrooms at the foot of the pier.


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


                 PRIMARY BENCH MARK STAMPING:  GLO 1
                         DESIGNATION:          877 3259 GLO-1

MONUMENTATION:           Bench Mark disk                       VM#:         9491
AGENCY:                  Texas General Land Office (TGLO)      IDB PID#:        
SETTING CLASSIFICATION:  Stainless steel rod                   OPUS PID#: DP0708
LATITUDE:   28° 38.4' N (  28.63933)          LONGITUDE:  96° 36.7' W ( -96.61208)


The primary bench mark is brass disk located 37.5 m (122.9 ft) WNW of the center
line of the park main road, 20.4 m (66.9 ft) NW of the entrance of the boat
ramp, 2.6 m (8.5 ft) WNW of the corner by the wooden bollard,  and 0.1 m (0.3
ft) in the grass in the corner made by an east-west and a north-south sidewalk
on the west side of the boat ramp, crimped to a stainless steel rod driven 10.2
m (40 feet) to refusal to refusal and encased in a 6-inch PVC pipe.

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

                                                                                
Station ID: 8773259                         PUBLICATION DATE:  08/15/2018
Name:       PORT LAVACA, LAVACA CAUSEWAY                      
            TX
NOAA Chart: 11317                           Latitude:   28° 38.4' N (  28.64060)
USGS Quad:  CALHOUN                         Longitude:  96° 36.6' W ( -96.60980)


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


                         BENCH MARK STAMPING:  GLO 2
                         DESIGNATION:          877 3259 GLO-2

MONUMENTATION:           Bench Mark disk                       VM#:         9492
AGENCY:                  Texas General Land Office (TGLO)      IDB PID#:        
SETTING CLASSIFICATION:  Stainless steel rod                   OPUS PID:        
LATITUDE:   28° 38.3' N (  28.63914)          LONGITUDE:  96° 36.8' W ( -96.61292)


The bench mark is a brass disk located on the approximate SE edge of the
right-of-way of Texas HWY 35, 90.0 m (295.3 ft) west of GLO 1, 23.8 south of a
highway light by Texas HWY 35, crimped to a stainless steel rod driven 13.7 m
(45 ft) to refusal and encased in a 6-inch PVC pipe without a kickblock.



                         BENCH MARK STAMPING:  GLO 3
                         DESIGNATION:          877 3259 GLO-3

MONUMENTATION:           Tidal Station disk                    VM#:         9493
AGENCY:                  Texas General Land Office (TGLO)      IDB PID#:        
SETTING CLASSIFICATION:  Stainless steel rod                   OPUS PID:        
LATITUDE:   28° 38.3' N (  28.63836)          LONGITUDE:  96° 36.8' W ( -96.61269)


The bench mark is a brass disk located in front of a covered camp site (#13) on
the easterly side of the park road leading to the pier, 90 m (295 ft) west from
bench mark GLO 2, 10.7 m (35.1 ft) north of cover campsite 43, 9.5 m (31.2 ft)
to the middle of the road, crimped to a stainless steel rod driven 13.7 m (45
ft) to refusal, and encased in a 6-inch PVC pipe.

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

                                                                                
Station ID: 8773259                         PUBLICATION DATE:  08/15/2018
Name:       PORT LAVACA, LAVACA CAUSEWAY                      
            TX
NOAA Chart: 11317                           Latitude:   28° 38.4' N (  28.64060)
USGS Quad:  CALHOUN                         Longitude:  96° 36.6' W ( -96.60980)


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


                         BENCH MARK STAMPING:  3259 A 2006
                         DESIGNATION:          877 3259 A

MONUMENTATION:           Bench Mark disk                       VM#:        22122
AGENCY:                  Conrad Blucher Institute (CBI)        IDB PID#:        
SETTING CLASSIFICATION:                                        OPUS PID:        
LATITUDE:   28° 38.4' N (  28.63986)          LONGITUDE:  96° 36.6' W ( -96.61064)


The bench mark is a brass disk set in the concrete sidewalk leading to the
fishing pier, located on the south side at the base of the pier, 19.5 m (64.0
ft) ESE of SE edge of the boat ramp channel, 11.55 m (37.89 ft) SW of the east
corner of the restrooms, and 1.5 m (4.9 ft) SSE of the centerline of the
sidewalk leading to the pier.

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

                                                                                
Station ID: 8773259                         PUBLICATION DATE:  08/15/2018
Name:       PORT LAVACA, LAVACA CAUSEWAY                      
            TX
NOAA Chart: 11317                           Latitude:   28° 38.4' N (  28.64060)
USGS Quad:  CALHOUN                         Longitude:  96° 36.6' W ( -96.60980)


                            T I D A L   D A T U M S 


Tidal datums at PORT LAVACA, LAVACA CAUSEWAY based on:

     LENGTH OF SERIES:      1 YEAR
     TIME PERIOD:           August 2015 - July 2016
     TIDAL EPOCH:           2002-2006
     CONTROL TIDE STATION:  8773701 PORT O'CONNOR, MATAGORDA BAY


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

     HIGHEST OBSERVED WATER LEVEL (08/26/2017)         =  2.350
     MEAN HIGHER HIGH WATER                     MHHW   =  0.285
     MEAN HIGH WATER                            MHW    =  0.274
     MEAN SEA LEVEL                             MSL    =  0.155
     MEAN TIDE LEVEL                            MTL    =  0.144
     MEAN LOW WATER                             MLW    =  0.013
     MEAN LOWER LOW WATER                       MLLW   =  0.000
     LOWEST  OBSERVED WATER LEVEL (01/12/2018)         = -0.572

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MLLW        MHW

     GLO 1                                       1.002    0.728
     GLO 2                                       1.383    1.109
     GLO 3                                       1.296    1.022
     3259 A 2006                                 1.334    1.060


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

                                                                                
Station ID: 8773259                         PUBLICATION DATE:  08/15/2018
Name:       PORT LAVACA, LAVACA CAUSEWAY                      
            TX
NOAA Chart: 11317                           Latitude:   28° 38.4' N (  28.64060)
USGS Quad:  CALHOUN                         Longitude:  96° 36.6' W ( -96.60980)


                             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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