U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
Datums Page                                                        Page  1 of  8

                                                                                
Station ID: 8726492                         PUBLICATION DATE:  02/08/2011
Name:       MANGROVE POINT INSIDE                             
            FL
NOAA Chart: 11412                           Latitude:   27° 44.5' N (  27.74170)
USGS Quad:  RUSKIN                          Longitude:  82° 28.0' W ( -82.46670)


To reach the tidal bench marks from the Ruskin Post Office, drive 3.06 km (1.9
mi) SW on U.S. Route 41 to the bridge over the Little Manatee River, then 0.16
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 ft) west of the east shoreline of the Little Manatee River,
0.37 m (1.2 ft) NW of the west most part of the dock, the staff was 5.43 m (17.8
ft) SE of the gage, and the bench marks are along U.S. Route 41 and the old
highway bridge.


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


                 PRIMARY BENCH MARK STAMPING:  6492 A 1977
                         DESIGNATION:          872 6492 A TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:         6534
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:  AG7526
SETTING CLASSIFICATION:  Copper-clad steel rod                 OPUS PID:        
LATITUDE:   27° 44.6' N (  27.74330)          LONGITUDE:  82° 28.1' W ( -82.46830)


The primary bench mark is a disk set flush in the concrete slab of the southern
most picnic shelter and about 0.21 m (0.7 ft) above the level of the park road
in the middle of three palm trees, about 91.44 m (300.0 ft) ESE of bench mark
6492 E 1977, 37.19 m (122.0 ft) WNW of bench mark 6492 B 1977, 7.92 m (26.0 ft)
NE of the approximate centerline of a dirt track road, 7.01 m (23.0 ft) ESE of a
palm tree, 5.18 m (17.0 ft) west of a palm tree, and 0.55 m (1.8 ft) NE of a
palm tree.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  2 of  8

                                                                                
Station ID: 8726492                         PUBLICATION DATE:  02/08/2011
Name:       MANGROVE POINT INSIDE                             
            FL
NOAA Chart: 11412                           Latitude:   27° 44.5' N (  27.74170)
USGS Quad:  RUSKIN                          Longitude:  82° 28.0' W ( -82.46670)


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


                         BENCH MARK STAMPING:  6492 B 1977
                         DESIGNATION:          872 6492 B TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:         6535
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:  AG7527
SETTING CLASSIFICATION:  Concrete slab                         OPUS PID:        
LATITUDE:   27° 44.6' N (  27.74330)          LONGITUDE:  82° 28.1' W ( -82.46830)


The bench mark is a disk set flush in the concrete slab of the southern-most
picnic shelter and about 0.21 m (0.7 ft) above the level of the park road
located 7.13 m (23.4 ft) NE of the approximate centerline of a dirt road, 1.13 m
(3.7 ft) NE of the SW edge of the slab, and 0.70 m (2.3 ft) SW of the NW edge of
the slab.



                         BENCH MARK STAMPING:  6492 C 1977
                         DESIGNATION:          872 6492 C TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:         6536
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:  AG7528
SETTING CLASSIFICATION:  Copper-clad steel rod                 OPUS PID:        
LATITUDE:   27° 44.6' N (  27.74330)          LONGITUDE:  82° 28.1' W ( -82.46830)


The benchmark is a disk located 15.24 m (50.0 ft) SE of a bush palm, 8.53 m
(28.0 ft) NE of the centerline of the paved drive, and 0.67 m (2.2 ft) north of
the north corner of the paved parking lot.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  3 of  8

                                                                                
Station ID: 8726492                         PUBLICATION DATE:  02/08/2011
Name:       MANGROVE POINT INSIDE                             
            FL
NOAA Chart: 11412                           Latitude:   27° 44.5' N (  27.74170)
USGS Quad:  RUSKIN                          Longitude:  82° 28.0' W ( -82.46670)


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


                         BENCH MARK STAMPING:  6492 E 1977
                         DESIGNATION:          872 6492 E TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:         6537
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:  AG7529
SETTING CLASSIFICATION:  Copper-clad steel rod                 OPUS PID:        
LATITUDE:   27° 44.6' N (  27.74330)          LONGITUDE:  82° 28.1' W ( -82.46830)


The bench mark is a disk set flush in the concrete slab of the southern most
picnic shelter and located about 85.34 m (280.0 ft) SE of the northern most
picnic shelter, 21.95 m (72.0 ft) NE of the NE corner of the turnaround, 7.62 m
(25.0 ft) NE of the approximate centerline of a dirt track road, 5.03 m (16.5
ft) south of a 15-inch palm tree, 0.76 m (2.5 ft) NE of a 12-inch palm tree, and
0.21 m (0.7 ft) above the level of the paved road.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  4 of  8

                                                                                
Station ID: 8726492                         PUBLICATION DATE:  02/08/2011
Name:       MANGROVE POINT INSIDE                             
            FL
NOAA Chart: 11412                           Latitude:   27° 44.5' N (  27.74170)
USGS Quad:  RUSKIN                          Longitude:  82° 28.0' W ( -82.46670)


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


                         BENCH MARK STAMPING:  W 695 2007
                         DESIGNATION:          W 695

MONUMENTATION:           Survey disk                           VM#:        19654
AGENCY:                  Florida Dept. of Environmental
                         Protection (FLDEP)                    IDB PID#:  DL1732
SETTING CLASSIFICATION:  Concrete monument                     OPUS PID:        
LATITUDE:   27° 44.1' N (  27.73517)          LONGITUDE:  82° 27.9' W ( -82.46439)


The bench mark is a disk set in the top of a round concrete monument flush with
the ground and about level with the parkway, 16.09 m (52.8 ft) north of the
approximate centerline of a paved road leading west (a private drive), 11.89 m
(39.0 ft) west of the centerline of E.G. Simmons Parkway, 3.11 m (10.2 ft) north
of a wooden power pole #163292 (24991 33671) with one guy wire attached, 3.05 m
(10.0 ft) north of a carsonite witness post, and west for 3.30 km (2.05 mi) to
the junction of E.G. Simmons Parkway and the mark on the left.  NOTE:  A magnet
was imbedded in the ground on the south side of the monument.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  5 of  8

                                                                                
Station ID: 8726492                         PUBLICATION DATE:  02/08/2011
Name:       MANGROVE POINT INSIDE                             
            FL
NOAA Chart: 11412                           Latitude:   27° 44.5' N (  27.74170)
USGS Quad:  RUSKIN                          Longitude:  82° 28.0' W ( -82.46670)


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


                         BENCH MARK STAMPING:  MAX 1991
                         DESIGNATION:          MAX

MONUMENTATION:           Survey disk                           VM#:        19655
AGENCY:                  Hillsborough                          IDB PID#:  DG8994
SETTING CLASSIFICATION:  Concrete drain box                    OPUS PID:        
LATITUDE:   27° 44.4' N (  27.73947)          LONGITUDE:  82° 28.0' W ( -82.46639)


The bench mark is a disk set flush in top of a 4 foot square concrete drain box
located 18.23 m (59.8 ft) SW of a 7-inch palm tree, 9.54 m (31.3 ft) NE of the
west end of a stone wall, 8.44 m (27.7 ft) NW of the east end of a stone wall,
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, 3.17 m
(10.4 ft) west of a Nail and Hill County disk in the west edge of  pavement of
park exit road, 0.61 m (2.0 ft) below the road, 0.61 m (2.0 ft) east of a
carsonite witness post and Hillsborough County sticker, and 0.15 m (0.5 ft) west
of a witness post.  NOTE:  To reach the mark go to the entrance of E.G. Simmons
Park and the mark on the left, located just inside the park on the west side of
exit road.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  6 of  8

                                                                                
Station ID: 8726492                         PUBLICATION DATE:  02/08/2011
Name:       MANGROVE POINT INSIDE                             
            FL
NOAA Chart: 11412                           Latitude:   27° 44.5' N (  27.74170)
USGS Quad:  RUSKIN                          Longitude:  82° 28.0' W ( -82.46670)


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


                         BENCH MARK STAMPING:  6492 G 2007
                         DESIGNATION:          872 6492 G

MONUMENTATION:           Tidal Station disk                    VM#:        19656
AGENCY:                  Florida Dept. of Environmental
                         Protection (FLDEP)                    IDB PID#:  DL1876
SETTING CLASSIFICATION:  Concrete slab                         OPUS PID:        
LATITUDE:   27° 44.5' N (  27.74236)          LONGITUDE:  82° 28.0' W ( -82.46686)


The bench mark is a disk set flush in the concrete slab of the southern most
picnic shelter located 27.34 m (89.7 ft) NE of the approximate centerline of the
service road, 10.61 m (34.8 ft) east of the NW corner of the picnic shelter,
6.86 m (22.5 ft) SW of the approximate centerline of a dirt road, 0.76 m (2.5
ft) west of the SE corner of the picnic shelter, and about 0.21 m (0.7 ft) above
the level of the park road.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  7 of  8

                                                                                
Station ID: 8726492                         PUBLICATION DATE:  02/08/2011
Name:       MANGROVE POINT INSIDE                             
            FL
NOAA Chart: 11412                           Latitude:   27° 44.5' N (  27.74170)
USGS Quad:  RUSKIN                          Longitude:  82° 28.0' W ( -82.46670)


                            T I D A L   D A T U M S 


Tidal datums at MANGROVE POINT INSIDE based on:

     LENGTH OF SERIES:      5 MONTHS
     TIME PERIOD:           April 1977 - August 1977
     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   =  0.763
     MEAN HIGH WATER                            MHW    =  0.676
     North American Vertical Datum              NAVD88 =  0.502
     MEAN SEA LEVEL                             MSL    =  0.409
     MEAN TIDE LEVEL                            MTL    =  0.400
     MEAN LOW WATER                             MLW    =  0.125
     MEAN LOWER LOW WATER                       MLLW   =  0.000

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MLLW        MHW

     6492 A 1977                                 2.106    1.430
     6492 B 1977                                 2.515    1.839
     6492 C 1977                                 2.330    1.654
     6492 E 1977                                 2.201    1.525
     W 695 2007                                  1.917    1.241
     MAX 1991                                    2.382    1.706
     6492 G 2007                                 2.767    2.091


Foot Notes:

Geodetic heights of the bench marks meet all NOAA/NOS/NGS quality control
standards for Second Order, Class 1 leveling.  It is advised that a confirmation
set of levels be established for bench marks 6492 G 2007, MAX 1991, and W 695
2007 to verify height differences before using tidal bench mark elevation
information.

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

                                                                                
Station ID: 8726492                         PUBLICATION DATE:  02/08/2011
Name:       MANGROVE POINT INSIDE                             
            FL
NOAA Chart: 11412                           Latitude:   27° 44.5' N (  27.74170)
USGS Quad:  RUSKIN                          Longitude:  82° 28.0' W ( -82.46670)


                             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.