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

                                                                                
Station ID: 8724226                         PUBLICATION DATE:  05/12/2004
Name:       BIG PINE KEY, NORTH EAST SHORE                    
            FL
NOAA Chart: 11448                           Latitude:   24° 43.7' N (  24.72830)
USGS Quad:  SUMMERLAND KEY                  Longitude:  81° 23.2' W ( -81.38670)


To reach the tidal bench marks from the intersection of U.S. Highway 1 and State
Highway S-940, proceed NW on S-940 for 6.9 km (4.3 mi) to the end of the road. 
The bench marks are located at the end of the road and in the vicinity of a cut.
 The tide gage and staff were located in the cut.


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


                 PRIMARY BENCH MARK STAMPING:  NO 1 1974
                         DESIGNATION:          872 4226 TIDAL 1

MONUMENTATION:           Tidal Station disk                    VM#:         8997
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Copper-clad steel rod                 OPUS PID:        
LATITUDE:   24° 43.7' N (  24.72830)          LONGITUDE:  81° 23.2' W ( -81.38670)


The primary bench mark is a disk located at the intersection of a drainage ditch
and the south shore of the cut, 107 m (350 ft) east and 46 m (150 ft) south of
the end of S-940, 3 m (11 ft) SE of the south shore of the cut, and 1 m (4 ft)
west of a drainage ditch.  The bench mark is set 15 cm (0.5 ft) above the
ground, crimped to a copper-clad rod driven to refusal.



                         BENCH MARK STAMPING:  NO 2 1974
                         DESIGNATION:          872 4226 TIDAL 2

MONUMENTATION:           Tidal Station disk                    VM#:         8998
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Copper-clad steel rod                 OPUS PID:        
LATITUDE:   24° 43.7' N (  24.72830)          LONGITUDE:  81° 23.2' W ( -81.38670)


The bench mark is a disk set in concrete, 42 m (137 ft) SW of bench mark NO 1
1974, 15 m (50 ft) SE of the south shore of the cut, and 15 m (50 ft) NW of a
drainage ditch running parallel to the cut.  The bench mark is set 20 cm (0.8
ft) above the ground, crimped to a copper-clad rod driven to refusal.

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

                                                                                
Station ID: 8724226                         PUBLICATION DATE:  05/12/2004
Name:       BIG PINE KEY, NORTH EAST SHORE                    
            FL
NOAA Chart: 11448                           Latitude:   24° 43.7' N (  24.72830)
USGS Quad:  SUMMERLAND KEY                  Longitude:  81° 23.2' W ( -81.38670)


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


                         BENCH MARK STAMPING:  NO 3 1974
                         DESIGNATION:          872 4226 TIDAL 3

MONUMENTATION:           Tidal Station disk                    VM#:         8999
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Copper-clad steel rod                 OPUS PID:        
LATITUDE:   24° 43.7' N (  24.72830)          LONGITUDE:  81° 23.2' W ( -81.38670)


The bench mark is a disk set in concrete, approximately 46 m (150 ft) south and
12 m (38 ft) east of the end of S-940, 21 m (70 ft) west of the north shore of
the cut, and 3 m (9 ft) north of a dirt road leading to the cut.  The bench mark
is set 15 cm (0.5 ft) above the ground, crimped to a copper-clad rod driven to
refusal.



                         BENCH MARK STAMPING:  NO 4 1974
                         DESIGNATION:          872 4226 TIDAL 4

MONUMENTATION:           Tidal Station disk                    VM#:         9000
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Copper-clad steel rod                 OPUS PID:        
LATITUDE:   24° 43.7' N (  24.72830)          LONGITUDE:  81° 23.2' W ( -81.38670)


The bench mark is a disk set in concrete, 51 m (166 ft) NW of bench mark NO 3
1974, 15 m (50 ft) south of a drainage ditch running perpendicular to the road,
and 1 m (2 ft) north of the end of S-940 in the path of the road.  The bench
mark is set 15 cm (0.5 ft) above the ground, crimped to a copper-clad rod driven
to refusal.

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

                                                                                
Station ID: 8724226                         PUBLICATION DATE:  05/12/2004
Name:       BIG PINE KEY, NORTH EAST SHORE                    
            FL
NOAA Chart: 11448                           Latitude:   24° 43.7' N (  24.72830)
USGS Quad:  SUMMERLAND KEY                  Longitude:  81° 23.2' W ( -81.38670)


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


                         BENCH MARK STAMPING:  NO 5 1974
                         DESIGNATION:          872 4226 TIDAL 5

MONUMENTATION:           Tidal Station disk                    VM#:         9001
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Copper-clad steel rod                 OPUS PID:        
LATITUDE:   24° 43.7' N (  24.72830)          LONGITUDE:  81° 23.2' W ( -81.38670)


The bench mark is a disk, 56 m (184 ft) SW of bench mark NO 4 1974, 46 m (150
ft) south and 13 m (43 ft) west of the end of S-940, 31 m (101 ft) west of bench
mark NO 3 1974, and 11 m (35 ft) east of a drainage canal running parallel to
the road.  The bench mark is set 15 cm (0.5 ft) above the ground, crimped to a
copper-clad rod driven to refusal.

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

                                                                                
Station ID: 8724226                         PUBLICATION DATE:  05/12/2004
Name:       BIG PINE KEY, NORTH EAST SHORE                    
            FL
NOAA Chart: 11448                           Latitude:   24° 43.7' N (  24.72830)
USGS Quad:  SUMMERLAND KEY                  Longitude:  81° 23.2' W ( -81.38670)


                            T I D A L   D A T U M S 


Tidal datums at BIG PINE KEY, NORTH EAST SHORE based on:

     LENGTH OF SERIES:      1 MONTH
     TIME PERIOD:           October 1974 - October 1974
     TIDAL EPOCH:           1983-2001
     CONTROL TIDE STATION:  8724580 KEY WEST


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

     MEAN HIGHER HIGH WATER                     MHHW   =  0.458
     MEAN HIGH WATER                            MHW    =  0.403
     MEAN TIDE LEVEL                            MTL    =  0.241
     MEAN SEA LEVEL                             MSL    =  0.241
     MEAN LOW WATER                             MLW    =  0.079
     MEAN LOWER LOW WATER                       MLLW   =  0.000

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MLLW        MHW

     NO 1 1974                                   0.689    0.286
     NO 2 1974                                   0.836    0.433
     NO 3 1974                                   0.871    0.468
     NO 4 1974                                   1.130    0.727
     NO 5 1974                                   0.941    0.538


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

                                                                                
Station ID: 8724226                         PUBLICATION DATE:  05/12/2004
Name:       BIG PINE KEY, NORTH EAST SHORE                    
            FL
NOAA Chart: 11448                           Latitude:   24° 43.7' N (  24.72830)
USGS Quad:  SUMMERLAND KEY                  Longitude:  81° 23.2' W ( -81.38670)


                             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.