Superseded Bench Mark Sheet for 8725269, IMPERIAL RIVER ENTRANCE FL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:  07/31/1984
Station ID: 8725269                                SUPERCEDED DATE:   04/21/2003
Name:       IMPERIAL RIVER ENTRANCE, IMPERIAL RIVER           
            FLORIDA
NOAA Chart: 11426                                  Latitude:         26° 20.2' N
USGS Quad:  BONITA SPRINGS                         Longitude:        81° 49.8' W


To reach the tidal bench marks south of the Imperial River, from the
intersection of U.S. Highway 41 and Bonita Beach Road (County Road C864),
proceed west on Bonita Beach Road for 1.40 miles (2.3 km) to the intersection
with Imperial Shores Boulevard.  Continue 0.4 mile (0.6 km) north along Imperial
Shores Boulevard to Tarpon Avenue.  Turn left (west) and to the end of Tarpon
Avenue.  The dirt road leads to the Riverwood Estates, and the bench marks are
along the roads leading to the Riverwood Estates, and the gage site was on the
pier on the Imperial River at the end of the dirt road.


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


                 PRIMARY BENCH MARK STAMPING:  5269 D 1978

MONUMENTATION:           Survey Disk                               VM#:     7863
AGENCY:                                                            PID#:  AD7878
SETTING CLASSIFICATION:  Copper-Coated Steel Rod


The bench mark is NW of the intersection of Imperial Shores Boulevard with
Tarpon Avenue, 289.0 feet (88.1 m) ENE of Bench Mark 5269 C 1978, 60.5 feet
(18.4 m) SE of a cream colored stuco dwelling with Box No. 644, 42.0 feet (12.8
m) north of the centerline of Tarpon Avenue and 0.8 feet (0.24 m) south of a
cable TV pole.  The bench mark is crimped to a 5/8 inch copper-coated steel rod
driven 32.0 feet (9.8 m) to refusal.



                         BENCH MARK STAMPING:  5269 A 1978

MONUMENTATION:           Survey Disk                               VM#:     7860
AGENCY:                                                            PID#:  AD7876
SETTING CLASSIFICATION:  Concrete Post


The bench mark is on the property of the Riverwood Estates, 78.0 feet (23.8 m)
east of the small dock, 43.8 feet (13.4 m) west of a large pine, 16.0 feet (4.9
m) south of the riverss edge, 11.4 feet (3.5 m) south of a small single pine and
0.8 feet (0.2 m) south of a witness post, set into the top of a 3.0 foot (0.9 m)
concrete post, at ground level.

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

                                                   PUBLICATION DATE:  07/31/1984
Station ID: 8725269                                SUPERCEDED DATE:   04/21/2003
Name:       IMPERIAL RIVER ENTRANCE, IMPERIAL RIVER           
            FLORIDA
NOAA Chart: 11426                                  Latitude:         26° 20.2' N
USGS Quad:  BONITA SPRINGS                         Longitude:        81° 49.8' W


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


                         BENCH MARK STAMPING:  5269 B 1978

MONUMENTATION:           Survey Disk                               VM#:     7861
AGENCY:                                                            PID#:  AD7877
SETTING CLASSIFICATION:  Concrete Post


The bench mark is at the NE corner ofthe Tarpon Avenue dirt road and the drive
leading to Riverwood Estates, 503.0 feet (153.3 m) south of Bench Mark 5269 A
1978, 53.0 feet (16.2 m) north of the centerline of Tarpon Avenue, 33.0 feet
(10.1 m) east of the centerline of the entrance drive, 9.8 feet (3.0 m) SE of
the Riverwood Estates sign, 2.3 feet (0.7 m) south of a chainlink fence and 2.0
feet (0.6 m) south of a witness post, and is set into the top of a 3.0 foot (0.9
m) concrete post, at ground level.



                         BENCH MARK STAMPING:  5269 C 1978

MONUMENTATION:           Survey Disk                               VM#:     7862
AGENCY:                                                            PID:         
SETTING CLASSIFICATION:  Concrete Post


The bench mark is south of Tarpon Avenue and at the beginning of the Tarpon
Avenue dirt road which ends at Riverwood Estates, among a cluster of Palms,
337.0 feet (102.7 m) east of Bench Mark 5269 B 1978, 69.0 feet (21.0 m) north
ofthe north face of a concrete block dwelling, 40.0 feet (12.2 m) west of the
centerline of the driveway leading to the dwelling and 27.0 feet (8.2 m) south
of the centerline of Tarpon Avenue, and is set into the top of a 3.0 foot (0.9
m) concrete post, 0.4 foot (0.12 m) below the ground surface.

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

                                                   PUBLICATION DATE:  07/31/1984
Station ID: 8725269                                SUPERCEDED DATE:   04/21/2003
Name:       IMPERIAL RIVER ENTRANCE, IMPERIAL RIVER           
            FLORIDA
NOAA Chart: 11426                                  Latitude:         26° 20.2' N
USGS Quad:  BONITA SPRINGS                         Longitude:        81° 49.8' W


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


                         BENCH MARK STAMPING:  5269 E 1978

MONUMENTATION:           Survey Disk                               VM#:     7864
AGENCY:                                                            PID#:  AD7879
SETTING CLASSIFICATION:  Copper-Coated Steel Rod


The bench mark is at the SW corner of the intersection of Imperial Shores
Boulevard and Tarpon Avenue, 305.0 feet (93.0 m) SE of Bench Mark 5269 D 1978,
68.5 feet (20.9 m) NNE of the NE corner of a white block house, 50.0 feet (15.2
m) south of the centerline of Tarpon Avenue, 36.0 feet (11.0 m) west of Imperial
Shores Boulevard and 1.5 feet (0.5 m) NE of utility pole No. 36 EM-91.  The
bench mark is crimped to a 5/8 inch diameter copper-coated steel rod driven 26.0
feet (7.9 m) to refusal.

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

                                                   PUBLICATION DATE:  07/31/1984
Station ID: 8725269                                SUPERCEDED DATE:   04/21/2003
Name:       IMPERIAL RIVER ENTRANCE, IMPERIAL RIVER           
            FLORIDA
NOAA Chart: 11426                                  Latitude:         26° 20.2' N
USGS Quad:  BONITA SPRINGS                         Longitude:        81° 49.8' W


                            T I D A L   D A T U M S 


Tidal datums at IMPERIAL RIVER ENTRANCE, IMPERIAL RIVER based on:

     LENGTH OF SERIES:      5 MONTHS
     TIME PERIOD:           APRIL-AUGUST 1978
     TIDAL EPOCH:           1960-1978
     CONTROL TIDE STATION:  8725110 NAPLES


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

     HIGHEST OBSERVED WATER LEVEL (06/21/1978)         =   1.67
     MEAN HIGHER HIGH WATER                     MHHW   =   0.94
     MEAN HIGH WATER                            MHW    =   0.75
     MEAN TIDE LEVEL                            MTL    =   0.43
     MEAN LOW WATER                             MLW    =   0.11
     MEAN LOWER LOW WATER                       MLLW   =   0.00
     LOWEST  OBSERVED WATER LEVEL (04/01/1978)         =  -0.60

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In FEET above:

     Stamping or Designation                    MLLW        MHW

     5269 D 1978                                 2.76      2.01
     5269 A 1978                                 3.19      2.44
     5269 B 1978                                 3.36      2.61
     5269 C 1978                                 2.39      1.64
     5269 E 1978                                 4.35      3.60


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

                                                   PUBLICATION DATE:  07/31/1984
Station ID: 8725269                                SUPERCEDED DATE:   04/21/2003
Name:       IMPERIAL RIVER ENTRANCE, IMPERIAL RIVER           
            FLORIDA
NOAA Chart: 11426                                  Latitude:         26° 20.2' N
USGS Quad:  BONITA SPRINGS                         Longitude:        81° 49.8' 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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