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

                                                   PUBLICATION DATE:  07/29/1990
Station ID: 8729501                                SUPERCEDED DATE:   04/21/2003
Name:       VALPARAISO, BOGGY BAYOU, CHOCTAWHATCHEE BAY       
            FLORIDA
NOAA Chart: 11388                                  Latitude:         30° 30.1' N
USGS Quad:  NICEVILLE                              Longitude:        86° 29.5' W


To reach the tidal bench marks from the junction of State Highway 85 and State
Road 397 in Valparaiso, proceed south on State Road 397 for 0.4 mile (0.6 km) to
Bayshore Drive, then east on Bayshore Drive for 0.3 mile (0.5 km) to Spence Boat
Works.  The bench marks are along Bayshore Drive, and the tide gage and staff
were on the eastern most dock near Spence Boat Works.


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


                 PRIMARY BENCH MARK STAMPING:  9501 A 1977

MONUMENTATION:           Survey Disk                               VM#:    10126
AGENCY:                                                            PID#:  BG4634
SETTING CLASSIFICATION:  Concrete Manhole Foundation


The bench mark is set in the top of a concrete manhole foundation, 0.1 mile (0.2
km) east of the intersection of Bayshore Drive and State Road 397, 51.0 feet
(15.5 m) NE of the centerline of Bayshore Drive, 18.5 feet (5.6 m) east of a
power pole, 5.8 feet (1.8 m) east of the manhole cover, 2.4 feet (0.7 m) NE of
the SW face of the manhole foundation, and 1.0 foot (0.3 m) above ground level.



                         BENCH MARK STAMPING:  9501 B 1989

MONUMENTATION:           Survey Disk                               VM#:    10127
AGENCY:                                                            PID:         
SETTING CLASSIFICATION:  Concrete Step


The bench mark is set in the top of a concrete step which is the support for the
shore end of Valpariaso City Pier, on the west end of the step.

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

                                                   PUBLICATION DATE:  07/29/1990
Station ID: 8729501                                SUPERCEDED DATE:   04/21/2003
Name:       VALPARAISO, BOGGY BAYOU, CHOCTAWHATCHEE BAY       
            FLORIDA
NOAA Chart: 11388                                  Latitude:         30° 30.1' N
USGS Quad:  NICEVILLE                              Longitude:        86° 29.5' W


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


                         BENCH MARK STAMPING:  9501 C 1989

MONUMENTATION:           Survey Disk                               VM#:    10128
AGENCY:                                                            PID:         
SETTING CLASSIFICATION:  Concrete Step


The bench mark is set in the top of a concrete step which leads from Bayshore
Drive to the city pier, on the east end of the fifth step down from Bayshore
Drive.



                         BENCH MARK STAMPING:  NO I

MONUMENTATION:           Survey Disk                               VM#:    10129
AGENCY:                                                            PID#:  BG1509
SETTING CLASSIFICATION:  Concrete Retaining Wall


The bench mark is set in the top of a concrete retaining wall SE of the
intersection of Westview Avenue and Bayshore Drive, 63.0 feet (19.2 m) south of
the centerline of Bayshore Drive, 13.0 feet (4.0 m) west of the west face of the
gas station without gas at Spence Boat Works sanding area, 4.5 feet (1.4 m) east
of the east face of the shop, and 0.5 foot (0.2 m) above ground level.



                         BENCH MARK STAMPING:  NO II

MONUMENTATION:           Survey Disk                               VM#:    10130
AGENCY:                                                            PID#:  BG1510
SETTING CLASSIFICATION:  Chimney Foundation


The bench mark is set in the top of a concrete foundation for a chimney for a
two-story building, 45.0 feet (13.7 m) south of the centerline of Bayshore
Drive, 20.3 feet (6.2 m) NE of Bench Mark NO I, 16.7 feet (5.1 m) north of the
north side of a one-story building, 10.8 feet (3.3 m) SE of the NW corner of the
foundation, 9.7 feet (3.0 m) south of the NW corner of the building, and 0.5
foot (0.2 m) above ground level.

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

                                                   PUBLICATION DATE:  07/29/1990
Station ID: 8729501                                SUPERCEDED DATE:   04/21/2003
Name:       VALPARAISO, BOGGY BAYOU, CHOCTAWHATCHEE BAY       
            FLORIDA
NOAA Chart: 11388                                  Latitude:         30° 30.1' N
USGS Quad:  NICEVILLE                              Longitude:        86° 29.5' W


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


                         BENCH MARK STAMPING:  NO III

MONUMENTATION:           Survey Disk                               VM#:    10131
AGENCY:                                                            PID#:  BG1511
SETTING CLASSIFICATION:  Concrete Foundation


The bench mark is set in the top of a 10x12-foot (3x4 m) concrete foundation for
a windlass, 126.0 feet (38.4 m) SE of the junction of Westview Avenue and
Bayshore Drive, 73.0 feet (22.3 m) NNE of Bench Mark NO II, 27.5 feet (8.4 m)
south of the centerline of Bayshore Drive, and 3.0 feet (0.9 m) SE of the NW
corner of the foundation.



                         BENCH MARK STAMPING:  NO STAMPING 1

MONUMENTATION:           Survey Disk                               VM#:    10132
AGENCY:                                                            PID#:  BG4635
SETTING CLASSIFICATION:  Concrete Abutment


The bench mark is set in the north abutment at the NE corner of the State Road
397 bridge over Toms Bayou (bridge #H15), 14.0 feet (4.3 m) east of the
centerline of the northbound lane of the highway, 1.0 foot (0.3 m) above road
level, and partially covered by the bridge end rail.

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

                                                   PUBLICATION DATE:  07/29/1990
Station ID: 8729501                                SUPERCEDED DATE:   04/21/2003
Name:       VALPARAISO, BOGGY BAYOU, CHOCTAWHATCHEE BAY       
            FLORIDA
NOAA Chart: 11388                                  Latitude:         30° 30.1' N
USGS Quad:  NICEVILLE                              Longitude:        86° 29.5' W


                            T I D A L   D A T U M S 


Tidal datums at VALPARAISO, BOGGY BAYOU, CHOCTAWHATCHEE BAY based on:

     LENGTH OF SERIES:      56 HIGH & LOW WATERS
     TIME PERIOD:           FEBRUARY 10-APRIL 11, 1989
     TIDAL EPOCH:           1960-1978
     CONTROL TIDE STATION:  8729840 PENSACOLA


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

     HIGHEST OBSERVED WATER LEVEL (09/04/1977)         =   1.69
     MEAN HIGHER HIGH WATER                     MHHW   =   0.45
     MEAN HIGH WATER                            MHW    =   0.45
     MEAN TIDE LEVEL                            MTL    =   0.23
     MEAN LOW WATER                             MLW    =   0.00
     MEAN LOWER LOW WATER                       MLLW   =   0.00
     LOWEST  OBSERVED WATER LEVEL (02/25/1989)         =  -1.56

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In FEET above:

     Stamping or Designation                    MLLW        MHW

     9501 A 1977                                 4.19      3.74
     9501 B 1989                                 3.30      2.85
     9501 C 1989                                 5.76      5.31
     NO I                                        4.51      4.06
     NO II                                       4.57      4.12
     NO III                                      5.64      5.19
     NO STAMPING 1                              19.03     18.58


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

                                                   PUBLICATION DATE:  07/29/1990
Station ID: 8729501                                SUPERCEDED DATE:   04/21/2003
Name:       VALPARAISO, BOGGY BAYOU, CHOCTAWHATCHEE BAY       
            FLORIDA
NOAA Chart: 11388                                  Latitude:         30° 30.1' N
USGS Quad:  NICEVILLE                              Longitude:        86° 29.5' 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.