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Bench Mark Sheet for 8770971, Rollover Pass 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Superseded Epoch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Small blue map location marker Unpublished bench mark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: 8770971                         PUBLICATION DATE:  12/12/2018
Name:       ROLLOVER PASS                                     
            TX
NOAA Chart: 11331                           Latitude:   29° 30.9' N (  29.51556)
USGS Quad:  FROZEN POINT                    Longitude:  94° 30.6' W ( -94.51056)


To reach the tidal bench marks from the town of Gilchrist, go about 4.0 km (2.5
mi) to paved road on the right (about 0.8 km (0.5 mi) from Rollover Pass
bridge).  Turn onto said paved road which will lead to Dr. Lauderdale Public
Boat Ramp, and travel for about 1.1 km (0.7 mi) to shell surface road on the
right.  Follow shell road for about 91.44 m (300.0 ft) to where it makes a hard
tur to the left.  Follow to the left for about another 91.44 m (300.0 ft) to the
end of the road on the bay.  The tide station is on a structure near a wooden
fishing pier.  The staff is also fastened to the same structure.


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


                 PRIMARY BENCH MARK STAMPING:  LUB 0971 A 1994
                         DESIGNATION:          877 0971 A TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:        14095
AGENCY:                  National Ocean Service (NOS)          IDB PID:         
SETTING CLASSIFICATION:  Stainless steel rod                   OPUS PID:        
LATITUDE:   29° 30.9' N (  29.51533)          LONGITUDE:  94° 30.7' W ( -94.51108)


The primary bench mark is a brass disk located 33.19 m (108.89 ft) SW of the
edge of the pier, 16.15 m (52.99 ft) NE of the north corner of a house at lot
1765, and 0.55 m (1.80 ft) east of a wood utility pole.  The bench mark is
crimped to a stainless steel rod driven 16.8 m (55.1 ft) to refusal, and encased
in a 6-inch PVC pipe with concrete kickblock.

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

                                                                                
Station ID: 8770971                         PUBLICATION DATE:  12/12/2018
Name:       ROLLOVER PASS                                     
            TX
NOAA Chart: 11331                           Latitude:   29° 30.9' N (  29.51556)
USGS Quad:  FROZEN POINT                    Longitude:  94° 30.6' W ( -94.51056)


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


                         BENCH MARK STAMPING:  LUB 0971 C 1994
                         DESIGNATION:          877 0971 C TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:        14097
AGENCY:                  National Ocean Service (NOS)          IDB PID:         
SETTING CLASSIFICATION:  Stainless steel rod                   OPUS PID:        
LATITUDE:   29° 30.9' N (  29.51469)          LONGITUDE:  94° 30.6' W ( -94.51067)


The bench mark is a brass disk located 55.17 m (181.00 ft) SE of LUB 0971 B
1994, 40.23 m NE of LUB 0971 D 1994, 11.49 m (37.70 ft) south of the SW most
poling of a house lot 1750, 8.23 m (27.00 ft) ESE of the centerline of gravel
drive, and .52 m (1.71 ft) west of a wood utility pole.  The bench mark is
crimped to a stainless steel rod drven 16.8 m (55.1 ft) to refusal, and encased
in a 6 inch PVC pipe with concrete kickblock.  



                         BENCH MARK STAMPING:  LUB 0971 D 1994
                         DESIGNATION:          877 0971 D TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:        14098
AGENCY:                  National Ocean Service (NOS)          IDB PID#:  DO9992
SETTING CLASSIFICATION:  Stainless steel rod                   OPUS PID#: DO9992
LATITUDE:   29° 30.9' N (  29.51450)          LONGITUDE:  94° 30.7' W ( -94.51103)


The bench mark is a brass disk located 66.14 m (216.99 ft) ENE of the centerline
of Yaught Basin Road, 40.23 m (131.99 ft) SW of LUB 0971 C 1994, 3.57 m (11.71
ft) SSE of the centerline of drive and 1.83 m (6.00 ft) NW of a wood utility
pole. The bench mark is a brass disk crimped to a stainless steel rod driven
16.8 m (55.1 ft) to refusal and encased in a 6 inch PVC pipe with concrete
kickblock.  

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

                                                                                
Station ID: 8770971                         PUBLICATION DATE:  12/12/2018
Name:       ROLLOVER PASS                                     
            TX
NOAA Chart: 11331                           Latitude:   29° 30.9' N (  29.51556)
USGS Quad:  FROZEN POINT                    Longitude:  94° 30.6' W ( -94.51056)


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


                         BENCH MARK STAMPING:  0971 F 2017
                         DESIGNATION:          877 0971 F

MONUMENTATION:           Metal Rod                             VM#:        22626
AGENCY:                  National Ocean Service (NOS)          IDB PID:         
SETTING CLASSIFICATION:  Stainless steel rod with sleeve       OPUS PID:        
LATITUDE:   29° 30.7' N (  29.51089)          LONGITUDE:  94° 30.6' W ( -94.50992)


The bench mark is a stainless steel rod located 121 m (397 ft) NNW of bench mark
877 0971 G, 59.3 m (194.6 ft) WNW of the eleventh powerpole from State Highway
87, and 10.5 m (34.4 ft) SW of the centerline of Yacht Basin Road. The mark is a
stainless steel rod driven 17.2 m (56.4 ft) to refusal with a 1.2 m (4 ft)
sleeve and encased in a six inch PVC tube with a concrete kickblock.



                         BENCH MARK STAMPING:  0971 G 2017
                         DESIGNATION:          877 0971 G

MONUMENTATION:           Metal Rod                             VM#:        22627
AGENCY:                  National Ocean Service (NOS)          IDB PID:         
SETTING CLASSIFICATION:                                        OPUS PID:        
LATITUDE:   29° 30.6' N (  29.50989)          LONGITUDE:  94° 30.6' W ( -94.50942)


The mark is a stainless steel rod located 121 m (397 ft) SSE of bench mark 877
0971 F, 8.2 m (26.9 ft) SW of the centerline of Yacht Basin Road, and 1.4 m (4.6
ft) south of the nineth telephone pole starting from Highway 87. The mark is a
stainless steel rod driven 23 m (75.4 ft) to refusal with a 4 ft sleeve and is
encased in a six inch PVC with a concrete kickblock.

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

                                                                                
Station ID: 8770971                         PUBLICATION DATE:  12/12/2018
Name:       ROLLOVER PASS                                     
            TX
NOAA Chart: 11331                           Latitude:   29° 30.9' N (  29.51556)
USGS Quad:  FROZEN POINT                    Longitude:  94° 30.6' W ( -94.51056)


                            T I D A L   D A T U M S 


Tidal datums at ROLLOVER PASS based on:

     LENGTH OF SERIES:      10 MONTHS
     TIME PERIOD:           February 2016 - November 2016
     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:

     HIGHEST OBSERVED WATER LEVEL (08/27/2017)         =  1.310
     MEAN HIGHER HIGH WATER                     MHHW   =  0.443
     MEAN HIGH WATER                            MHW    =  0.411
     MEAN SEA LEVEL                             MSL    =  0.245
     MEAN TIDE LEVEL                            MTL    =  0.240
     MEAN LOW WATER                             MLW    =  0.068
     MEAN LOWER LOW WATER                       MLLW   =  0.000
     LOWEST  OBSERVED WATER LEVEL (01/17/2018)         = -0.427

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MLLW        MHW

     LUB 0971 A 1994                             1.470    1.059
     LUB 0971 C 1994                             1.915    1.504
     LUB 0971 D 1994                             2.036    1.625
     0971 F 2017                                 0.615    0.204
     0971 G 2017                                 0.689    0.278


Foot Notes:

Bench marks 0971 F 2017 and 0971 G 2017 are based on one differential leveling
connection and do not meet the quality control standards of the NOS. Therefore,
caution should be used when deriving elevations for these marks.

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

                                                                                
Station ID: 8770971                         PUBLICATION DATE:  12/12/2018
Name:       ROLLOVER PASS                                     
            TX
NOAA Chart: 11331                           Latitude:   29° 30.9' N (  29.51556)
USGS Quad:  FROZEN POINT                    Longitude:  94° 30.6' W ( -94.51056)


                             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 8770971 Rollover Pass, TX

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