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

                                                                                
Station ID: 8726436                         PUBLICATION DATE:  08/05/2005
Name:       LITTLE MANATEE RIVER                              
            FL
NOAA Chart: 11412                           Latitude:   27° 42.3' N (  27.70500)
USGS Quad:  RUSKIN                          Longitude:  82° 26.9' W ( -82.44830)


To reach the tidal bench marks from the Ruskin Post Office, drive 3.0 km (1.9
mi) SW on U.S. Route 41 to the bridge over the Little Manatee River, then 0.2 km
(0.1 mi) north from the east end of the four lane concrete bridge on U.S. Route
41 over the Little Manatee River, to the Paradise Mobile Court for mobile homes
which is on the north (right) side of the highway, and west to an old concrete
bridge.  The tide gage was on a wooden dock at the Paradise Mobile court, 10.67
m (35.0 mi) west of the east shoreline of the Little Manatee River, 0.37 m (1.2
mi) NW of the west most part of the dock, the staff was 5.43 m (17.8 mi) SE of
the gage, and the bench marks are along U.S. Route 41 and the old highway
birdge.


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


                 PRIMARY BENCH MARK STAMPING:  6436 A 1977
                         DESIGNATION:          872 6436 A 1977

MONUMENTATION:           Survey disk                           VM#:        12116
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:  AG7553
SETTING CLASSIFICATION:  Concrete bridge curbing               OPUS PID:        
LATITUDE:   27° 42.3' N (  27.70500)          LONGITUDE:  82° 26.9' W ( -82.44830)


The primary bench mark is a disk set flush in the bridge surface 0.15 m (0.5 ft)
above the surface of the road, 9.39 m (30.8 ft) south of the SE corner of the
south bound lane bridge for U.S. Route 41, 5.33 m (17.5 ft) north of the
centerline of the north bound lane of the bridge, and 0.55 m (1.8 ft) east of
the NE edge of the bridge.

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

                                                                                
Station ID: 8726436                         PUBLICATION DATE:  08/05/2005
Name:       LITTLE MANATEE RIVER                              
            FL
NOAA Chart: 11412                           Latitude:   27° 42.3' N (  27.70500)
USGS Quad:  RUSKIN                          Longitude:  82° 26.9' W ( -82.44830)


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


                         BENCH MARK STAMPING:  6436 B 1977
                         DESIGNATION:          872 6436 B 1977

MONUMENTATION:           Survey disk                           VM#:        12117
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:  AG7551
SETTING CLASSIFICATION:  Concrete drain box                    OPUS PID#: AG7551
LATITUDE:   27° 42.3' N (  27.70500)          LONGITUDE:  82° 26.9' W ( -82.44830)


The bench mark is a disk set flush in top of a 1.22  (4.0 ft) square concrete
drain box 0.61 m (2.0 ft) below the road, 23.07 m (75.7 ft) east of the west end
of the curb for the cross-over road east of the bridge, 11.46 m (37.6 ft) south
of the centerline of the south bound lane, 9.63 m (31.6 ft) north of the
centerline of the north bound lane, and 0.15 m (0.5 ft) west of the witness
post.



                         BENCH MARK STAMPING:  6436 C 1977
                         DESIGNATION:          872 6436 C 1977

MONUMENTATION:           Survey disk                           VM#:        12118
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:  AG7552
SETTING CLASSIFICATION:  Concrete drain box                    OPUS PID#: AG7552
LATITUDE:   27° 42.3' N (  27.70500)          LONGITUDE:  82° 26.9' W ( -82.44830)


The bench mark is a disk set flush in top of a 1.22 m (4.0 ft) square concrete
drain box 0.61 m (2.0 ft) below the road, 111.25 m (365.0 ft) east of Bench Mark
6436 A 1977, 48 m (157 ft) west of Bench Mark 6436 B 1977, 10.67 m (35.0 ft)
north of the centerline of the north bound lane, 9.81 m (32.2 ft) west of the
east end of the median curb for the cross-over road, and 9.66 m (31.7 ft) south
of the centerline of the south bound lane.

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

                                                                                
Station ID: 8726436                         PUBLICATION DATE:  08/05/2005
Name:       LITTLE MANATEE RIVER                              
            FL
NOAA Chart: 11412                           Latitude:   27° 42.3' N (  27.70500)
USGS Quad:  RUSKIN                          Longitude:  82° 26.9' W ( -82.44830)


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


                         BENCH MARK STAMPING:  6436 D
                         DESIGNATION:          872 6436 D

MONUMENTATION:           Survey disk                           VM#:        12119
AGENCY:                  State Road Department                 IDB PID#:  AG7554
SETTING CLASSIFICATION:  Rail                                  OPUS PID:        
LATITUDE:   27° 42.3' N (  27.70500)          LONGITUDE:  82° 26.9' W ( -82.44830)


The bench mark is a disk set in top of the bridge rail 0.91 m (3.0 ft) above the
surface of the bridge over the Little Manatee River on U.S. Route 41, 6.95 m
(22.8 ft) north of the centerline of the south bound lane of the U.S. Route 41
bridge, and 1.80 m (5.9 ft) west of the NE corner of the south bound lane of the
bridge.



                         BENCH MARK STAMPING:  LMR4 1961 JACKSONVILLE
                         DESIGNATION:          872 6436 LMR4 1961 JACKS

MONUMENTATION:           Survey disk                           VM#:        12120
AGENCY:                  COE                                   IDB PID#:  AG6194
SETTING CLASSIFICATION:  Concrete bridge walkway               OPUS PID:        
LATITUDE:   27° 42.3' N (  27.70500)          LONGITUDE:  82° 26.9' W ( -82.44830)


The bench mark is a disk set flush in the bridge surface 0.15 m (0.5 ft) above
the surface of the road, 7.62 m (25.0 ft) NE of Bench Mark 6436 D, 6.74 m (22.1
ft) west of a witness post, 5.03 m (16.5 ft) north of the centerline of the old
bridge, 4.60 m (15.1 ft) west of the NE corner of the old bridge, and 0.61 m
(2.0 ft) south of the north edge of the old bridge.

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

                                                                                
Station ID: 8726436                         PUBLICATION DATE:  08/05/2005
Name:       LITTLE MANATEE RIVER                              
            FL
NOAA Chart: 11412                           Latitude:   27° 42.3' N (  27.70500)
USGS Quad:  RUSKIN                          Longitude:  82° 26.9' W ( -82.44830)


                            T I D A L   D A T U M S 


Tidal datums at LITTLE MANATEE RIVER based on:

     LENGTH OF SERIES:      4 MONTHS
     TIME PERIOD:           December 1978 - March 1979
     TIDAL EPOCH:           1983-2001
     CONTROL TIDE STATION:  8726520 ST. PETERSBURG, TAMPA BAY


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

     MEAN HIGHER HIGH WATER                     MHHW   =  0.606
     MEAN HIGH WATER                            MHW    =  0.549
     North American Vertical Datum              NAVD88 =  0.390
     MEAN SEA LEVEL                             MSL    =  0.314
     MEAN TIDE LEVEL                            MTL    =  0.314
     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

     6436 A 1977                                 8.453    7.904
     6436 B 1977                                 3.945    3.396
     6436 C 1977                                 4.729    4.180
     6436 D                                      8.803    8.254
     LMR4 1961 JACKSONVILLE                      4.624    4.075


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

                                                                                
Station ID: 8726436                         PUBLICATION DATE:  08/05/2005
Name:       LITTLE MANATEE RIVER                              
            FL
NOAA Chart: 11412                           Latitude:   27° 42.3' N (  27.70500)
USGS Quad:  RUSKIN                          Longitude:  82° 26.9' W ( -82.44830)


                             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.