U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
Datums Page                                                        Page  1 of  6

                                                   PUBLICATION DATE:  02/13/1988
Station ID: 8724967                                SUPERCEDED DATE:   04/21/2003
Name:       MARCO ISLAND, CAXAMBAS PASS                       
            FLORIDA
NOAA Chart: 11429                                  Latitude:         25° 54.5' N
USGS Quad:  MARCO ISLAND                           Longitude:        81° 43.7' W


To reach the tidal bench marks from the intersection of County Highway 953 and
State Highway 951 (Collier Boulevard), proceed south on Collier Boulevard for
3.4 miles (5.5 km) to the Deltona Corporation property.  The bench marks are
located along Swallow Avenue, Collier Boulevard, and on Deltona Corporation
property.  The tide gage and staff were located on the seawall south of Bench
Mark CAXAMBAS 1959 1975.


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


                 PRIMARY BENCH MARK STAMPING:  CAXAMBAS 1959 1975

MONUMENTATION:           Survey Disk                               VM#:     9730
AGENCY:                                                            PID#:  AC3260
SETTING CLASSIFICATION:  Concrete Filled Terra-cotta Pipe


The bench mark is set in the top of a concrete filled terra-cotta pipe just
south of the pump house on Deltona Corporation Property, west of where a paved
private road becomes a dirt road on the Deltona Corporation property, 375 feet
(114 m) SE of the north corner of the bulkhead, 102 feet (31 m) NW of utility
pole T-11355, 55 feet (17 m) south of a dilapidated chain link fence, 4 feet (1
m) west of a witness post, 0.5 foot (0.2 m) east of another witness post, and
0.7 foot (0.2 m) above ground level.



                         BENCH MARK STAMPING:  NO 3 CAXAMBAS 1959 1975

MONUMENTATION:           Survey Disk                               VM#:     9731
AGENCY:                                                            PID#:  AE4423
SETTING CLASSIFICATION:  Concrete Pad


The bench mark is set flush in the SE corner of a concrete pad at the pump house
on Deltona Corporation property, 23 feet (7 m) NE of Bench Mark CAXAMBAS 1959
1975, and 14.5 feet (4.4 m) NW of a light pole.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  2 of  6

                                                   PUBLICATION DATE:  02/13/1988
Station ID: 8724967                                SUPERCEDED DATE:   04/21/2003
Name:       MARCO ISLAND, CAXAMBAS PASS                       
            FLORIDA
NOAA Chart: 11429                                  Latitude:         25° 54.5' N
USGS Quad:  MARCO ISLAND                           Longitude:        81° 43.7' W


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


                         BENCH MARK STAMPING:  NO 4 CAXAMBAS 1959 1975

MONUMENTATION:           Survey Disk                               VM#:     9732
AGENCY:                                                            PID#:  AE4424
SETTING CLASSIFICATION:  Concrete Pad


The bench mark is set flush in the SW corner of a concrete pad at the pump house
on Deltona Corporation property, 30.7 feet (9.4 m) west of Bench Mark NO 3
CAXAMBAS 1959 1975, and 18.8 feet (5.7 m) NW of Bench Mark CAXAMBAS 1959 1975.



                         BENCH MARK STAMPING:  NO 1 1976

MONUMENTATION:           Survey Disk                               VM#:     9733
AGENCY:                                                            PID#:  AC3259
SETTING CLASSIFICATION:  Concrete Pad


The bench mark is set in a concrete pad at building #12906 in the SW section of
Deltona Corporation property, 78 feet (24 m) east of the inside edge of the sea
wall, 42 feet (13 m) NE of a light pole #51071A, 20.5 feet (6.2 m) south of the
steps to the warehouse building, and 3 feet (1 m) west of the SW corner of the
warehouse building.



                         BENCH MARK STAMPING:  NO 5 1976

MONUMENTATION:           Survey Disk                               VM#:     9734
AGENCY:                                                            PID:         
SETTING CLASSIFICATION:  Concrete Pad


The bench mark is set flush in a concrete pad at building #12902, 198 feet (60
m) SE of Bench Mark NO 7 1976, 150 feet (46 m) SE of the center of the east
gate, 71 feet (22 m) south of the centerline of the paved road, 4.9 feet (1.5 m)
SE of a witness sign, and 1 foot (0.3 m) NW of the NW corner of building #12702.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  3 of  6

                                                   PUBLICATION DATE:  02/13/1988
Station ID: 8724967                                SUPERCEDED DATE:   04/21/2003
Name:       MARCO ISLAND, CAXAMBAS PASS                       
            FLORIDA
NOAA Chart: 11429                                  Latitude:         25° 54.5' N
USGS Quad:  MARCO ISLAND                           Longitude:        81° 43.7' W


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


                         BENCH MARK STAMPING:  NO 7 1976

MONUMENTATION:           Survey Disk                               VM#:     9735
AGENCY:                                                            PID#:  AC3261
SETTING CLASSIFICATION:  Copper-clad Steel Rod


The bench mark is 66 feet (20 m) west of the centerline of a paved road leading
south from Collier Boulevard, 48 feet (15 m) NE of the east entrance to the
Deltona Corporation property, and 1.3 feet (0.4 m) south of a power pole with a
witness sign.  The bench mark is at ground level, crimped to a copper-clad steel
rod driven 40 feet (12 m) to refusal, and encased in a 4-inch PVC pipe and
concrete kickblock.



                         BENCH MARK STAMPING:  4967 A 1979

MONUMENTATION:           Survey Disk                               VM#:     9736
AGENCY:                                                            PID#:  AC3262
SETTING CLASSIFICATION:  Copper-clad Steel Rod


The bench mark is 315 feet (96 m) north of Bench Mark NO 7 1976, 74.0 feet (22.6
m) WSW of the centerpoint of the first crossover after the bend in Collier
Boulevard, 3.5 feet (1.1 m) SE of a green UTS telephone junction box #1100-1,
and 1.0 foot (0.3 m) east of power pole #T2826 with a witness sign attached. 
The bench mark is 0.1 foot (0.03 m) above the ground, crimped to a copper-clad
steel rod driven 48 feet (15 m) to refusal, and encased in a pipe.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  4 of  6

                                                   PUBLICATION DATE:  02/13/1988
Station ID: 8724967                                SUPERCEDED DATE:   04/21/2003
Name:       MARCO ISLAND, CAXAMBAS PASS                       
            FLORIDA
NOAA Chart: 11429                                  Latitude:         25° 54.5' N
USGS Quad:  MARCO ISLAND                           Longitude:        81° 43.7' W


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


                         BENCH MARK STAMPING:  4967 B 1979

MONUMENTATION:           Survey Disk                               VM#:     9737
AGENCY:                                                            PID#:  AC3263
SETTING CLASSIFICATION:  Copper-clad Steel Rod


The bench mark is 164 feet (50 m) NE of Bench Mark 4967 A 1979, 83.5 feet (25.5
m) SSE of the SE corner of Island Club Condominium (a yellow 3-story stucco
building), 32.0 feet (9.8 m) north of the centerline of Collier Boulevard
(northbound land), 20.3 feet (6.2 m) SE of the SE corner of the parking lot, 2.5
feet (0.8 m) east of a concrete power pole, and 3 feet (1 m) east of a witness
post.  The bench mark is at ground level, crimped to a copper-clad steel rod
driven 48 feet (15 m) to refusal, and encased in a pipe.



                         BENCH MARK STAMPING:  4967 C 1979

MONUMENTATION:           Survey Disk                               VM#:    10543
AGENCY:                                                            PID#:  AC3264
SETTING CLASSIFICATION:  Copper-clad Steel Rod


The bench mark is 266 feet (81 m) north of Bench Mark 4967 B 1979, 80.9 feet
(24.7 m) NNE of the NE corner of Island Club Condominium (a yellow 3-story
stucco building), 39.9 feet (12.2 m) south of the centerline of Swallow Avenue,
1.0 foot (0.3 m) west of a concrete power pole with a witness sign, and 0.8 foot
(0.2 m) south of the south edge of the sidewalk.  The bench mark is at ground
level, crimped to a copper-clad steel rod driven 64 feet (20 m) to refusal and
encased in a pipe.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  5 of  6

                                                   PUBLICATION DATE:  02/13/1988
Station ID: 8724967                                SUPERCEDED DATE:   04/21/2003
Name:       MARCO ISLAND, CAXAMBAS PASS                       
            FLORIDA
NOAA Chart: 11429                                  Latitude:         25° 54.5' N
USGS Quad:  MARCO ISLAND                           Longitude:        81° 43.7' W


                            T I D A L   D A T U M S 


Tidal datums at MARCO ISLAND, CAXAMBAS PASS based on:

     LENGTH OF SERIES:      29 MONTHS
     TIME PERIOD:           MARCH 1976-DECEMBER 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 (06/02/1977)         =   4.72
     MEAN HIGHER HIGH WATER                     MHHW   =   3.12
     MEAN HIGH WATER                            MHW    =   2.89
     MEAN TIDE LEVEL                            MTL    =   1.74
     MEAN LOW WATER                             MLW    =   0.59
     MEAN LOWER LOW WATER                       MLLW   =   0.00
     LOWEST  OBSERVED WATER LEVEL (01/18/1976)         =  -1.56

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In FEET above:

     Stamping or Designation                    MLLW        MHW

     CAXAMBAS 1959 1975                          6.73      3.84
     NO 3 CAXAMBAS 1959 1975                     6.17      3.28
     NO 4 CAXAMBAS 1959 1975                     6.23      3.34
     NO 1 1976                                   9.92      7.03
     NO 5 1976                                   8.90      6.01
     NO 7 1976                                   6.51      3.62
     4967 A 1979                                 7.77      4.88
     4967 B 1979                                 7.80      4.91
     4967 C 1979                                 6.94      4.05


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

                                                   PUBLICATION DATE:  02/13/1988
Station ID: 8724967                                SUPERCEDED DATE:   04/21/2003
Name:       MARCO ISLAND, CAXAMBAS PASS                       
            FLORIDA
NOAA Chart: 11429                                  Latitude:         25° 54.5' N
USGS Quad:  MARCO ISLAND                           Longitude:        81° 43.7' 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.