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Bench Mark Sheet for 8720832, Welaka FL

Superseded Epoch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Small blue map location marker Unpublished bench mark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  7

                                                                                
Station ID: 8720832                         PUBLICATION DATE:  11/01/2011
Name:       WELAKA, ST. JOHNS RIVER                           
            FL
NOAA Chart: 11495                           Latitude:   29° 28.6' N (  29.47670)
USGS Quad:  WELAKA                          Longitude:  81° 40.5' W ( -81.67500)


To reach the tidal bench marks from the intersection of State Road 308B (Oak
Street) and State Road 309 in Welaka, proceed west on State Road 308B for 0.24
km (0.15 mi) to Front Street, then south on Front Street for 0.5 km (0.3 mi) to
the dirt road leading west to the Greene residence, the house just to the north
of Trail Boss Campgrounds.  The bench marks are along Front and Elm Streets. 
The tide gage and staff were on the west end of the northernmost finger dock
behind the Greene residence.


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


                 PRIMARY BENCH MARK STAMPING:  0832 C 1995
                         DESIGNATION:          872 0832 C

MONUMENTATION:           Flange-encased Rod                    VM#:        16183
AGENCY:                  National Ocean Service (NOS)          IDB PID#:        
SETTING CLASSIFICATION:  Stainless steel rod                   OPUS PID:        
LATITUDE:   29° 28.6' N (  29.47670)          LONGITUDE:  81° 40.5' W ( -81.67500)


The primary bench mark is a flange-encased rod set near the intersection of
Front and Palmetto Streets, 54.86 m (180.0 ft) west of the intersection, 18.20 m
(59.7 ft) south of the SW corner of the Palms Restaurant, 12.10 m (39.7 ft)
north of the center of Palmetto Street, 0.82 m (2.7 ft) south of a carsonite
witness post, and about 2 m (6 ft) above the level of Palmetto Street. The datum
point is the top of a stainless steel rod driven 17.7 m (58 ft) to refusal, and
encased in a PVC pipe and NOS logo cap.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  2 of  7

                                                                                
Station ID: 8720832                         PUBLICATION DATE:  11/01/2011
Name:       WELAKA, ST. JOHNS RIVER                           
            FL
NOAA Chart: 11495                           Latitude:   29° 28.6' N (  29.47670)
USGS Quad:  WELAKA                          Longitude:  81° 40.5' W ( -81.67500)


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


                         BENCH MARK STAMPING:  N 19 1933 22.903
                         DESIGNATION:          N 19

MONUMENTATION:           Bench Mark disk                       VM#:         5256
AGENCY:                  US Coast and Geodetic Survey
                         (USC&GS)                              IDB PID#:  AQ0678
SETTING CLASSIFICATION:  Concrete monument                     OPUS PID:        
LATITUDE:   29° 28.7' N (  29.47830)          LONGITUDE:  81° 40.5' W ( -81.67500)


The bench mark is a disk set in the top of a concrete monument at the
intersection of Front and Elm Streets, across from Welaka Civic Hall, 9 m (30
ft) north of the centerline of Elm Street, 9 m (29 ft) east of the centerline of
Front Street, 1 m (2 ft) east of a flagpole at the SW corner of a concrete block
building, and 3 cm (0.1 ft) above ground level.



                         BENCH MARK STAMPING:  NO 1 1934
                         DESIGNATION:          872 0832 TIDAL 1

MONUMENTATION:           Bench Mark disk                       VM#:         5257
AGENCY:                  US Coast and Geodetic Survey
                         (USC&GS)                              IDB PID#:  AQ2571
SETTING CLASSIFICATION:  Concrete monument                     OPUS PID:        
LATITUDE:   29° 28.8' N (  29.48000)          LONGITUDE:  81° 40.4' W ( -81.67330)


The bench mark is a disk set in a concrete monument at the intersection of Front
and Palmetto Streets, 12.56 m (41.2 ft) east of the centerline of Front Street,
5.67 m (18.6 ft) north of the centerline of Palmetto Street, 0.15 m (0.5 ft) NW
of power pole #3-3724-1203-0-6, and 9 cm (0.3 ft) above ground level.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  3 of  7

                                                                                
Station ID: 8720832                         PUBLICATION DATE:  11/01/2011
Name:       WELAKA, ST. JOHNS RIVER                           
            FL
NOAA Chart: 11495                           Latitude:   29° 28.6' N (  29.47670)
USGS Quad:  WELAKA                          Longitude:  81° 40.5' W ( -81.67500)


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


                         BENCH MARK STAMPING:  WELAKA 1935
                         DESIGNATION:          WELAKA

MONUMENTATION:           Triangulation Station disk            VM#:         5258
AGENCY:                  US Coast and Geodetic Survey
                         (USC&GS)                              IDB PID#:  AQ1775
SETTING CLASSIFICATION:  Concrete monument                     OPUS PID:        
LATITUDE:   29° 28.6' N (  29.47670)          LONGITUDE:  81° 40.4' W ( -81.67330)


The bench mark is a disk set in a square concrete monument in an open area near
the river, 81 m (265 ft) south of the post office, 46 m (150 ft) east of the
river, 40 m (132 ft) west of the centerline of a paved street, 15 m (49 ft) SSE
of the SW corner of an old garage, 4 m (14 ft) north of a yard fence, 0.30 m
(1.0 ft) east of a metal witness post, and 6 cm (0.2 ft) above ground level.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  4 of  7

                                                                                
Station ID: 8720832                         PUBLICATION DATE:  11/01/2011
Name:       WELAKA, ST. JOHNS RIVER                           
            FL
NOAA Chart: 11495                           Latitude:   29° 28.6' N (  29.47670)
USGS Quad:  WELAKA                          Longitude:  81° 40.5' W ( -81.67500)


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


                         BENCH MARK STAMPING:  WELAKA 1935 NO 4 1968
                         DESIGNATION:          WELAKA RM 4

MONUMENTATION:           Reference Mark disk                   VM#:         5259
AGENCY:                  US Coast and Geodetic Survey
                         (USC&GS)                              IDB PID#:  AQ1774
SETTING CLASSIFICATION:  Concrete monument                     OPUS PID:        
LATITUDE:   29° 28.6' N (  29.47670)          LONGITUDE:  81° 40.4' W ( -81.67330)


The bench mark is a disk set in a concrete monument in the SE corner of an open
area, 46 m (150 ft) east of the river, 9 m (30 ft) west of the centerline of a
paved street, 0.67 m (2.2 ft) north of the fence corner with a 3 x 3-inch square
concrete property corner stake, and at ground level.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  5 of  7

                                                                                
Station ID: 8720832                         PUBLICATION DATE:  11/01/2011
Name:       WELAKA, ST. JOHNS RIVER                           
            FL
NOAA Chart: 11495                           Latitude:   29° 28.6' N (  29.47670)
USGS Quad:  WELAKA                          Longitude:  81° 40.5' W ( -81.67500)


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


                         BENCH MARK STAMPING:  WELAKA 1935 NO 3 1968
                         DESIGNATION:          WELAKA RM 3

MONUMENTATION:           Reference Mark disk                   VM#:        16182
AGENCY:                  US Coast and Geodetic Survey
                         (USC&GS)                              IDB PID#:  AQ1776
SETTING CLASSIFICATION:  Concrete ramp                         OPUS PID:        
LATITUDE:   29° 28.7' N (  29.47830)          LONGITUDE:  81° 40.5' W ( -81.67500)


The bench mark is a disk set in a concrete foundation near the intersection of
Front  and Oak streets, 32.0 m (105.0 ft) west of the centerline of Front
Street, 18.3 cm (0.6 ft) south of the west edge of a door to a garage, and 0.3 m
(1.0 ft) south of a carsonite witness post.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  6 of  7

                                                                                
Station ID: 8720832                         PUBLICATION DATE:  11/01/2011
Name:       WELAKA, ST. JOHNS RIVER                           
            FL
NOAA Chart: 11495                           Latitude:   29° 28.6' N (  29.47670)
USGS Quad:  WELAKA                          Longitude:  81° 40.5' W ( -81.67500)


                            T I D A L   D A T U M S 


Tidal datums at WELAKA, ST. JOHNS RIVER based on:

     LENGTH OF SERIES:      6 MONTHS
     TIME PERIOD:           October 2003 - March 2004
     TIDAL EPOCH:           1983-2001
     CONTROL TIDE STATION:  8720503 RED BAY POINT, ST JOHNS RIVER


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

     MEAN HIGHER HIGH WATER                     MHHW   =  0.148
     MEAN HIGH WATER                            MHW    =  0.143
     MEAN TIDE LEVEL                            MTL    =  0.078
     MEAN SEA LEVEL                             MSL    =  0.076
     MEAN LOW WATER                             MLW    =  0.013
     MEAN LOWER LOW WATER                       MLLW   =  0.000
     North American Vertical Datum              NAVD88 = -0.006

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MLLW        MHW

     0832 C 1995                                 4.196    4.053
     N 19 1933 22.903                            6.692    6.549
     NO 1 1934                                   6.783    6.640
     WELAKA 1935                                 6.667    6.524
     WELAKA 1935 NO 4 1968                       6.976    6.833
     WELAKA 1935 NO 3 1968                       6.594    6.451


Foot Notes:

 

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  7 of  7

                                                                                
Station ID: 8720832                         PUBLICATION DATE:  11/01/2011
Name:       WELAKA, ST. JOHNS RIVER                           
            FL
NOAA Chart: 11495                           Latitude:   29° 28.6' N (  29.47670)
USGS Quad:  WELAKA                          Longitude:  81° 40.5' W ( -81.67500)


                             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 8720832 Welaka, FL

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