Superseded Bench Mark Sheet for 8720219, Dames Point FL

Present Epoch

Printable version

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

                                                   PUBLICATION DATE:  11/30/1987
Station ID: 8720219                                SUPERCEDED DATE:   04/21/2003
Name:       DAME POINT, ST. JOHNS RIVER                       
            FLORIDA
NOAA Chart: 11488                                  Latitude:         30° 23.5' N
USGS Quad:  EASTPORT                               Longitude:        81° 33.9' W


To reach the tidal bench marks from the intersection of U.S. Highway 17 (Main
Street) and Heckscher Drive (County Road 105) in Jacksonville, proceed east on
Heckscher Drive for 4.68 miles (7.53 km) (over the Dunn Creek bridge) to August
Drive, then SE along August Drive for 1.6 miles (2.6 km) to the residence at
9050 August Drive.  The bench marks are located on the bridge, along Heckscher
Drive, Dame Point Road, and August Drive.  The tide gage and staff were located
on a dock at 9050 August Drive.


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


                 PRIMARY BENCH MARK STAMPING:  0219 F 1977

MONUMENTATION:           Survey Disk                               VM#:     5110
AGENCY:                                                            PID#:  BC1551
SETTING CLASSIFICATION:  Concrete Monument


The bench mark is set in the top of a concrete monument at 9050 August Drive,
0.1 mile (0.2 km) NW of the intersection of August Drive and Dame Point Road,
57.5 feet (17.5 m) NW of power pole #9044, 30 feet (9 m) SW of the centerline of
August Drive, 3 feet (1 m) NE of a witness sign, and about level with August
Drive.



                         BENCH MARK STAMPING:  J 325 1970

MONUMENTATION:           Survey Disk                               VM#:     5109
AGENCY:                                                            PID#:  BC0281
SETTING CLASSIFICATION:  Concrete Monument


The bench mark is set in the top of a concrete monument along County Road 105,
about 0.6 mile (1.0 km) east of the east end of the County Road 105 bridge over
Dunn Creek,93 feet (28 m) south of the SE corner of Heckscher Drive Baptist
Church, 56 feet (17 m) west of the centerline of the entrance drive to the
church, 43 feet (13 m) north of the centerline of the highway, 9.5 feet (2.9 m)
of the west end of a 12-inch pipe culvert under the driveway, and 0.2 foot (0.1
m) above the ground.

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

                                                   PUBLICATION DATE:  11/30/1987
Station ID: 8720219                                SUPERCEDED DATE:   04/21/2003
Name:       DAME POINT, ST. JOHNS RIVER                       
            FLORIDA
NOAA Chart: 11488                                  Latitude:         30° 23.5' N
USGS Quad:  EASTPORT                               Longitude:        81° 33.9' W


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


                         BENCH MARK STAMPING:  0219 D

MONUMENTATION:           Survey Disk                               VM#:     5111
AGENCY:                                                            PID#:  BC1550
SETTING CLASSIFICATION:  Copper-clad Steel Rod


The bench mark is at the intersection of Dame Point Road and August Drive about
1.6 miles (2.6 km) south of Heckscher Drive (County Road 105), 76.6 feet (23.3
m) east of a cabbage palm, 56.1 feet (17.1 m) NW of power pole #30, and 34.5
feet (10.5 m) west of the centerline of Dame Point Road.  The bench mark is 1
foot (0.3 m) below Dame Point Road level, crimped to a copper-clad steel rod
driven 28 feet (9 m) to refusal and encased by a concrete kickblock.



                         BENCH MARK STAMPING:  0219 E

MONUMENTATION:           Survey Disk                               VM#:     5112
AGENCY:                                                            PID#:  BC1549
SETTING CLASSIFICATION:  Copper-clad Steel Rod


The bench mark is at the intersection of New Berlin Road and Dame Point Road
about 0.9 mile (1.4 km) SE of Heckscher Drive (County Road 105), 195 feet (59 m)
south of the intersection, 37 feet (11 m) NE of the northernmost rail at the
intersection of a railroad and Dame Point Road, 23 feet (7 m) east of the
centerline of Dame Point Road, and 2 feet (1 m) west of a witness post.  The
bench marks is 2 feet (1 m) below Dame Point Road, crimped to a copper-clad
stainless steel rod driven 48 feet (15 m) to refusal and encased by a concrete
kickblock.

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

                                                   PUBLICATION DATE:  11/30/1987
Station ID: 8720219                                SUPERCEDED DATE:   04/21/2003
Name:       DAME POINT, ST. JOHNS RIVER                       
            FLORIDA
NOAA Chart: 11488                                  Latitude:         30° 23.5' N
USGS Quad:  EASTPORT                               Longitude:        81° 33.9' W


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


                         BENCH MARK STAMPING:  H 325

MONUMENTATION:           Survey Disk                               VM#:     5113
AGENCY:                                                            PID#:  BC0280
SETTING CLASSIFICATION:  Concrete Sidewalk


The bench mark is set in the top of the east end of the north concrete sidewalk
of the County Road 105 bridge over Dunn Creek, 17.8 feet (5.4 m) north of the
centerline of the highway, 0.8 foot (0.2 m) west of the east end of the
sidewalk, 0.3 foot (0.1 m) south of the south face of the north concrete
guardrail of the bridge, and 1 foot (0.3 m) above the highway level.

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

                                                   PUBLICATION DATE:  11/30/1987
Station ID: 8720219                                SUPERCEDED DATE:   04/21/2003
Name:       DAME POINT, ST. JOHNS RIVER                       
            FLORIDA
NOAA Chart: 11488                                  Latitude:         30° 23.5' N
USGS Quad:  EASTPORT                               Longitude:        81° 33.9' W


                            T I D A L   D A T U M S 


Tidal datums at DAME POINT, ST. JOHNS RIVER based on:

     LENGTH OF SERIES:      5 MONTHS
     TIME PERIOD:           SEPTEMBER 1977-JANUARY 1978
     TIDAL EPOCH:           1960-1978
     CONTROL TIDE STATION:  8720220 MAYPORT


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

     HIGHEST OBSERVED WATER LEVEL (11/02/1977)         =   4.34
     MEAN HIGHER HIGH WATER                     MHHW   =   3.44
     MEAN HIGH WATER                            MHW    =   3.29
     MEAN TIDE LEVEL                            MTL    =   1.70
   * NATIONAL GEODETIC VERTICAL DATUM           NGVD29 =   1.25
     MEAN LOW WATER                             MLW    =   0.10
     MEAN LOWER LOW WATER                       MLLW   =   0.00
     LOWEST  OBSERVED WATER LEVEL (01/10/1978)         =  -1.22

   * NGVD reference based on elevations published in Quad 300813, 1973, and NOS
     leveling of 1978. 
North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In FEET above:

     Stamping or Designation                    MLLW        MHW

     0219 F 1977                                 8.43      5.14
     J 325 1970                                  8.08      4.79
     0219 D                                     11.17      7.88
     0219 E                                      5.83      2.54
     H 325                                      11.36      8.07


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

                                                   PUBLICATION DATE:  11/30/1987
Station ID: 8720219                                SUPERCEDED DATE:   04/21/2003
Name:       DAME POINT, ST. JOHNS RIVER                       
            FLORIDA
NOAA Chart: 11488                                  Latitude:         30° 23.5' N
USGS Quad:  EASTPORT                               Longitude:        81° 33.9' W


                             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 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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