U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
Datums Page                                                        Page  1 of  4

                                                   PUBLICATION DATE:  02/13/1988
Station ID: 8726632                                SUPERCEDED DATE:   04/21/2003
Name:       ARCHIE CREEK, HILLSBOROUGH BAY                    
            FLORIDA
NOAA Chart: 11413                                  Latitude:         27° 52.9' N
USGS Quad:  TAMPA                                  Longitude:        82° 23.8' W


To reach the tidal bench marks from the south end of the U.S. Highway 41 bridge
over Palm River, proceed south on U.S. Highway 41 for 4.6 miles (7.4 km) to the
bridge over Archie Creek.  The bench marks are located along U.S. Highway 41. 
The tide gage and staff were located on the west side of the bridge.


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


                 PRIMARY BENCH MARK STAMPING:  6632 A 1977

MONUMENTATION:           Survey Disk                               VM#:     6633
AGENCY:                                                            PID#:  AG7469
SETTING CLASSIFICATION:  Concrete Culvert


The bench mark is set flush in a concrete culvert, 60 feet (18 m) NW of the SE
end of the culvert headwall, 29 feet (9 m) SW of the centerline of the
southbound lane of U.S. Highway 41, 3 feet (1 m) SE of the NW end of the culvert
headwall, and 2 feet (1 m) below the highway.



                         BENCH MARK STAMPING:  6632 B 1977

MONUMENTATION:           Survey Disk                               VM#:     6634
AGENCY:                                                            PID#:  AG7468
SETTING CLASSIFICATION:  Concrete Drain


The bench mark is set flush in a 6 x 7-foot (2 x 2 m) concrete drain box with an
iron gate, 65.0 feet (19.8 m) ESE of Bench Mark 6632 A 1977, 36.7 feet (11.2 m)
SW of the centerline of the northbound lane of U.S. Highway 41, 29.5 feet (9.0
m) NE of the centerline of the southbound lane, and 2 feet (1 m) below the
highway.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  2 of  4

                                                   PUBLICATION DATE:  02/13/1988
Station ID: 8726632                                SUPERCEDED DATE:   04/21/2003
Name:       ARCHIE CREEK, HILLSBOROUGH BAY                    
            FLORIDA
NOAA Chart: 11413                                  Latitude:         27° 52.9' N
USGS Quad:  TAMPA                                  Longitude:        82° 23.8' W


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


                         BENCH MARK STAMPING:  6632 C 1977

MONUMENTATION:           Survey Disk                               VM#:     6635
AGENCY:                                                            PID#:  AG7467
SETTING CLASSIFICATION:  Concrete Culvert


The bench mark is set flush in a concrete culvert, 69.5 feet (21.2 m) ESE of
Bench Mark 6632 B 1977, 26.5 feet (8.1 m) NE of the centerline of the northbound
lane of U.S. Highway 41, 0.8 foot (0.2 m) NW of the SE end of the culvert
headwall, and 2 feet (1 m) below the highway.



                         BENCH MARK STAMPING:  6632 E 1977

MONUMENTATION:           Survey Disk                               VM#:     6636
AGENCY:                                                            PID#:  AG7466
SETTING CLASSIFICATION:  Concrete Monument


The bench mark is set in the top of a concrete monument, 575 feet (175 m) south
of Bench Mark 6632 C 1977, 78 feet (24 m) NE of the centerline of the northbound
lane of U.S. Highway 41, 3.5 feet (1.1 m) SW of the SW end of a billboard sign
with a witness sign attached, 4 feet (1 m) below the highway, and level with the
ground.



                         BENCH MARK STAMPING:  6632 F 1977

MONUMENTATION:           Survey Disk                               VM#:     6637
AGENCY:                                                            PID#:  AG7465
SETTING CLASSIFICATION:  Copper-clad Steel Rod


The bench mark is 345 feet (105 m) SSW of Bench Mark 6632 E 1977, 33.5 feet
(10.2 m) SW of the centerline of the northbound lane of U.S. Highway 41, 33.5
feet (10.2 m) NE of the centerline of the southbound lane, and 6 feet (2 m)
north of the north curb of the median cross-over road.  The bench mark is level
with the highway, crimped to a copper-clad steel rod driven an unspecified depth
to refusal, and encased in a 4-inch PVC pipe and concrete kickblock.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  3 of  4

                                                   PUBLICATION DATE:  02/13/1988
Station ID: 8726632                                SUPERCEDED DATE:   04/21/2003
Name:       ARCHIE CREEK, HILLSBOROUGH BAY                    
            FLORIDA
NOAA Chart: 11413                                  Latitude:         27° 52.9' N
USGS Quad:  TAMPA                                  Longitude:        82° 23.8' W


                            T I D A L   D A T U M S 


Tidal datums at ARCHIE CREEK, HILLSBOROUGH BAY based on:

     LENGTH OF SERIES:      2 MONTHS
     TIME PERIOD:           MARCH-APRIL 1977
     TIDAL EPOCH:           1960-1978
     CONTROL TIDE STATION:  8726537 APOLLO BEACH


Elevations of tidal datums referred to Mean High Water (MHW), in FEET:

     HIGHEST OBSERVED WATER LEVEL (12/21/1976)         =   1.53
     MEAN HIGHER HIGH WATER                     MHHW   =   0.18
     MEAN HIGH WATER                            MHW    =   0.00

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In FEET above:

     Stamping or Designation                                MHW

     6632 A 1977                                           5.09
     6632 B 1977                                           4.96
     6632 C 1977                                           4.98
     6632 E 1977                                           2.71
     6632 F 1977                                           8.79


Foot Notes:

The datums were computed by the NOS Direct Method due to flat low  waters.

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

                                                   PUBLICATION DATE:  02/13/1988
Station ID: 8726632                                SUPERCEDED DATE:   04/21/2003
Name:       ARCHIE CREEK, HILLSBOROUGH BAY                    
            FLORIDA
NOAA Chart: 11413                                  Latitude:         27° 52.9' N
USGS Quad:  TAMPA                                  Longitude:        82° 23.8' 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.