U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
Datums Page                                                        Page  1 of  9

                                                                                
Station ID: 8724580                                PUBLICATION DATE:  09/07/2010
Name:       KEY WEST                                          
            FLORIDA
NOAA Chart: 11447                                  Latitude:         24° 33.3' N
USGS Quad:  KEY WEST                               Longitude:        81° 48.5' W


To reach the tidal bench marks from Key West International Airport, proceed west
on Roosevelt Boulevard for 3.9 km (2.4 mi) to White Street, then NW on White
Street for 2.3 km (1.4 mi) to Southard Street, turn left onto Southard Street
and go west to the U.S. Naval Reservation main gate at Thomas Street,  continue
0.3 km (0.2 mi) to a second gate at Emma Street.  The bench marks are on the
Naval Base, near the County Courthouse, and along Front Street in downtown Key
West.  The tide gauge is located on the concrete sea wall near the north
property line of the Naval Base.  NOTE:  A pass to enter the Naval Base must be
obtained at the Boca Chica Naval Air Station.


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


                 PRIMARY BENCH MARK STAMPING:  4580 E 1998
                         DESIGNATION:          872 4580 E

MONUMENTATION:           Flange-encased Rod                        VM#:    13915
AGENCY:                  National Ocean Service (NOS)              PID#:  AJ2450
SETTING CLASSIFICATION:  Stainless steel rod in sleeve


The primary bench mark is a flange-encased rod located at 44.17 m (144.91 ft)
east of the west inside face of the concrete pier face, 37.70 m (123.69 ft) NNE
of the NE corner of a two story white block building, 37.19 m (122.01 ft) SE of
the SE corner of a concrete electrical building, 25.79 m (84.61 ft) west of the
east chain link property fence, and 25.69 m (84.28 ft) east of the third light
pole south of the north end of the property.  The datum point is the top of a
stainless steel rod driven 7.0 m (23.0 ft) to refusal, inside a sleeve to a
depth of 0.9 m (2.95 ft) and encased in a 5-inch NOS logo cap.  NOTE- Sleeve
depth does not meet the specifications for a class A rod mark.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  2 of  9

                                                                                
Station ID: 8724580                                PUBLICATION DATE:  09/07/2010
Name:       KEY WEST                                          
            FLORIDA
NOAA Chart: 11447                                  Latitude:         24° 33.3' N
USGS Quad:  KEY WEST                               Longitude:        81° 48.5' W


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


                         BENCH MARK STAMPING:  29 1923 8.140
                         DESIGNATION:          872 4580 TIDAL 29

MONUMENTATION:           Tidal Station disk                        VM#:      706
AGENCY:                  US Coast and Geodetic Survey (USC&GS)     PID#:  AA0009
SETTING CLASSIFICATION:  Concrete wall of a building


The bench mark is a disk set vertically in the east concrete wall and at the NE
corner of  a private residence , 12.04 m (39.5 ft) west of the west curb of
Front street (extended from the City of Key West), 10.67 m (35.01 ft) south of
the south curb of Eaton Street, and 1.22 m (4.00 ft)  above the level of the
ground.



                         BENCH MARK STAMPING:  24 1923 6.529
                         DESIGNATION:          872 4580 TIDAL 24

MONUMENTATION:           Tidal Station disk                        VM#:      710
AGENCY:                  US Coast and Geodetic Survey (USC&GS)     PID#:  AA0003
SETTING CLASSIFICATION:  Concrete pillar of a building


The bench mark is a disk set vertically in the NW concrete face of a concrete
pillar near the west corner of Cavanaghs Clothing Store, 2.90 m (9.51 ft) SE of
the SE curb of front street, 1.83 m (6.00 ft) NE of the NE curb of ann street,
0.15 m (0.49 ft) NE of the west corner of the building, and 1.25 m (4.10 ft)
above the level of sidewalk.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  3 of  9

                                                                                
Station ID: 8724580                                PUBLICATION DATE:  09/07/2010
Name:       KEY WEST                                          
            FLORIDA
NOAA Chart: 11447                                  Latitude:         24° 33.3' N
USGS Quad:  KEY WEST                               Longitude:        81° 48.5' W


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


                         BENCH MARK STAMPING:  25 1923 5.292
                         DESIGNATION:          872 4580 TIDAL 25

MONUMENTATION:           Tidal Station disk                        VM#:      711
AGENCY:                  US Coast and Geodetic Survey (USC&GS)     PID#:  AA0004
SETTING CLASSIFICATION:  Massive structure


The bench mark is a disk set vertically in a wall of the SE bank, close to the
corner at the east side of the corner entrance, 11 m (36.1 ft) SE of the
centerline of Front street, 2.3 m (7.5 ft) SW of the SW curb of Duval Street,
and 0.8 m (2.6 ft) above the pavement.



                         BENCH MARK STAMPING:  26 1923 9.482
                         DESIGNATION:          872 4580 TIDAL 26

MONUMENTATION:           Tidal Station disk                        VM#:      712
AGENCY:                  US Coast and Geodetic Survey (USC&GS)     PID#:  AA0005
SETTING CLASSIFICATION:  Brick wall of a building


The bench mark is a disk set vertically in the east brick wall of the Key West
museum of art and history across the street from Mel Fisher museum, 45.7 m
(149.9 ft) SW of the center of the street intersection, 12.71 m (41.699 ft) west
of the west curb of Front street, 10.33 m (33.89 ft) south of the NE corner of
the building, 0.91 m (2.99 ft) north of the north end of the third step from top
at entrace to building and about 1.07 m (3.51 ft) above the level of the ground.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  4 of  9

                                                                                
Station ID: 8724580                                PUBLICATION DATE:  09/07/2010
Name:       KEY WEST                                          
            FLORIDA
NOAA Chart: 11447                                  Latitude:         24° 33.3' N
USGS Quad:  KEY WEST                               Longitude:        81° 48.5' W


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


                         BENCH MARK STAMPING:  30 1923 16.417
                         DESIGNATION:          872 4580 TIDAL 30

MONUMENTATION:           Tidal Station disk                        VM#:      714
AGENCY:                  US Coast and Geodetic Survey (USC&GS)     PID#:  AA0007
SETTING CLASSIFICATION:  Courthouse wall


The bench mark is a disk set vertically in the NE face of the old County
Courthouse, 30.2 m (99.1 ft) SW of the SW curb of Whitehead Street, 14.6 m (47.9
ft) NW of the center of the NE entrance to the building, 0.30 m (0.98 ft) SE of
the north corner of the building, and 1.07 m (3.51 ft) above the ground.



                         BENCH MARK STAMPING:  14.324
                         DESIGNATION:          872 4580 TIDAL BASIC

MONUMENTATION:           Bench Mark disk                           VM#:      716
AGENCY:                  US Coast and Geodetic Survey (USC&GS)     PID#:  AA0008
SETTING CLASSIFICATION:  Concrete post


The bench mark is a disk set flush in the top of a concrete monument  bearing
the inscription United States Coast and Geodetic Survey basic bench mark, 21.64
m (70.9 ft) east of the north corner of the old County Courthouse, 9.91 m (32.51
ft) SW of the SW curb of Whitehead Street, 6.71 m (22.01 ft) from a low cement
wall on the Whitehead street side of the County Courthouse grounds, 5.79 m (19.0
ft) north of the edge of a walk leading to the front steps of the courthouse,
2.93 m (9.61 ft) NW of the NW curb of the NE entrance to the old courthouse, and
0.9 m (3.0 ft) above the level of the sidewalk.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  5 of  9

                                                                                
Station ID: 8724580                                PUBLICATION DATE:  09/07/2010
Name:       KEY WEST                                          
            FLORIDA
NOAA Chart: 11447                                  Latitude:         24° 33.3' N
USGS Quad:  KEY WEST                               Longitude:        81° 48.5' W


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


                         BENCH MARK STAMPING:  KH-8 1962 JAX
                         DESIGNATION:          KH 8

MONUMENTATION:           Survey disk                               VM#:     1781
AGENCY:                  US Army Corps of Engineers (USE)          PID#:  AA1753
SETTING CLASSIFICATION:  Dock


The bench mark is a disk set in the concrete dock 85.95 m (281.99 ft) west of
the NE corner of the dock, 12.59 m (41.3 ft) east of the NW corner of the dock,
and 0.67 m (2.20 ft) north of the north edge of the dock.  Note -In order to
survey to this mark you must obtain permission from captain  Chad Cummingham
director of marina operation for Hilton, phone number 305-294-4000.



                         BENCH MARK STAMPING:  4580 C 1992
                         DESIGNATION:          872 4580 C

MONUMENTATION:           Tidal Station disk                        VM#:    12415
AGENCY:                  National Ocean Survey (NOS)               PID:         
SETTING CLASSIFICATION:  Mooring bollard


The bench mark is a disk set in the concrete surface of the second mooring
bollard south of the Admirals Slip along the sea wall near the tide station,
25.90 m (84.97 ft) west of the U.S. Navy property line fence on the east side of
the condominiums, 20.73 m (68.01 ft) north of the NW corner of the northern-most
water valve pit, 14.33 m (47.01 ft) south of the south face of the Admirals
Slip, 1.37m (4.49 ft) east of the east face of the concrete bulkhead, and 0.18 m
(0.59 ft) above the concrete deck.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  6 of  9

                                                                                
Station ID: 8724580                                PUBLICATION DATE:  09/07/2010
Name:       KEY WEST                                          
            FLORIDA
NOAA Chart: 11447                                  Latitude:         24° 33.3' N
USGS Quad:  KEY WEST                               Longitude:        81° 48.5' W


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


                         BENCH MARK STAMPING:  4580 D 1993
                         DESIGNATION:          872 4580 D

MONUMENTATION:           Tidal Station disk                        VM#:    13696
AGENCY:                  National Ocean Service (NOS)              PID:         
SETTING CLASSIFICATION:  mooring bollard


The bench mark is a disk set in a concrete pad for a mooring bollard,
approximately 183 m (600.4 ft) south of the gage house, 49.07 m (160.99 ft) NW
of third light pole south of the gage house, 21.64 m (71.00 ft) south of the
middle concrete pad housing ship to shore power, 10.80 m (35.43 ft) NW of the NW
corner of the Concrete Power Building, and 0.91 m (2.99 ft) east of the sea
wall.



                         BENCH MARK STAMPING:  KEY WEST GSL 1989
                         DESIGNATION:          KEY WEST GSL

MONUMENTATION:           Horizontal Station disk                   VM#:    15837
AGENCY:                  US Coast and Geodetic Survey (USC&GS)     PID#:  AA1645
SETTING CLASSIFICATION:  Sea wall


The bench mark is a disk set in the concrete sea wall of the outer most pier,
0.6 km (0.35 mi) north along the outer most pier from its south end, near the
start of the curve of the sea wall to the NE, 22.25 m (73.00 ft) NW of the
concrete base of the last light pole at the NNE end of the pier, 10.36 m (33.989
ft) SSW of a steel ladder attached to the NW side of the sea wall, 0.91 m (2.99
ft) north of the north corner of a bollard, and 0.91 m (2.99 ft) ESE of the WNW
edge of the sea wall.  Note - special request must be submitted to the naval
base authorities to get access and survey to this mark

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  7 of  9

                                                                                
Station ID: 8724580                                PUBLICATION DATE:  09/07/2010
Name:       KEY WEST                                          
            FLORIDA
NOAA Chart: 11447                                  Latitude:         24° 33.3' N
USGS Quad:  KEY WEST                               Longitude:        81° 48.5' W


                            T I D A L   D A T U M S 


Tidal datums at KEY WEST based on:

     LENGTH OF SERIES:      19 YEARS
     TIME PERIOD:           January 1983 - December 2001
     TIDAL EPOCH:           1983-2001
     CONTROL TIDE STATION:   


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

     HIGHEST OBSERVED WATER LEVEL (10/24/2005)         =  1.507
     MEAN HIGHER HIGH WATER                     MHHW   =  0.551
     North American Vertical Datum              NAVD88 =  0.538
     MEAN HIGH WATER                            MHW    =  0.463
     MEAN SEA LEVEL                             MSL    =  0.272
     MEAN TIDE LEVEL                            MTL    =  0.268
     MEAN LOW WATER                             MLW    =  0.073
     MEAN LOWER LOW WATER                       MLLW   =  0.000
     LOWEST  OBSERVED WATER LEVEL (02/19/1928)         = -0.506

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MLLW        MHW

     4580 E 1998                                 1.726    1.263
     29 1923 8.140                               2.592    2.129
     24 1923 6.529                               2.059    1.596
     25 1923 5.292                               1.681    1.217
     26 1923 9.482                               3.009    2.546
     30 1923 16.417                              5.132    4.669
     14.324                                      4.497    4.034
     KH-8 1962 JAX                               2.986    2.523
     4580 C 1992                                 2.504    2.041
     4580 D 1993                                 2.494    2.031
     KEY WEST GSL 1989                           2.100    1.637


                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  8 of  9

                                                                                
Station ID: 8724580                                PUBLICATION DATE:  09/07/2010
Name:       KEY WEST                                          
            FLORIDA
NOAA Chart: 11447                                  Latitude:         24° 33.3' N
USGS Quad:  KEY WEST                               Longitude:        81° 48.5' W


Foot Notes:

Bench mark Key West GSL 1989 is based on one differential leveling connection
and does not meet the quality control standards of the NOS.  Therefore, caution
should be used when deriving elevations for this mark. 

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  9 of  9

                                                                                
Station ID: 8724580                                PUBLICATION DATE:  09/07/2010
Name:       KEY WEST                                          
            FLORIDA
NOAA Chart: 11447                                  Latitude:         24° 33.3' N
USGS Quad:  KEY WEST                               Longitude:        81° 48.5' 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.