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

                                                                                
Station ID: 8667178                         PUBLICATION DATE:  05/23/2003
Name:       POINT OF PINES, N. EDISTO R.                      
            SC
NOAA Chart: 11522                           Latitude:   32° 35.1' N (  32.58500)
USGS Quad:  ROCKVILLE                       Longitude:  80° 13.7' W ( -80.22830)


To reach the tidal bench marks from Edisto Island Post Office, proceed NE on
County Road S-10-1452 for 3.1 km (1.9 mi) until the paved road becomes a dirt
road, then proceed on the private dirt road for 2.7 km (1.7 mi) to the west bank
of North Edisto River.  The bench marks are along the berm line and adjacent
field.  The tide gauge and staff were on a platform constructed 61 m (200 ft)
offshore NE of bench mark 7178 E 1977.


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


                 PRIMARY BENCH MARK STAMPING:  7178 E 1977
                         DESIGNATION:          866 7178 E TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:        11317
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:  CK2515
SETTING CLASSIFICATION:  Galvanized steel rod                  OPUS PID:        
LATITUDE:   32° 35.1' N (  32.58500)          LONGITUDE:  80° 13.6' W ( -80.22670)


The primary bench mark is a disk located along the beach just above the berm
line, 19.20 m (63.0 ft) SSE of a 1.07 m (3.5 ft) diameter oak tree, 16.31 m
(53.5 ft) north of a cluster of three oak trees, 16.03 m (52.6 ft) east of a
lone 0.3 m (1 ft) diameter palmetto tree, 4.88 m (16.0 ft) SE of an old barb
wire fence leading into the river, and 0.91 m (3.0 ft) east of a witness post. 
The bench mark is 6 cm (0.2 ft) above the ground, crimped to a galvanized steel
rod driven 11.3 m (37 ft) 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  2 of  6

                                                                                
Station ID: 8667178                         PUBLICATION DATE:  05/23/2003
Name:       POINT OF PINES, N. EDISTO R.                      
            SC
NOAA Chart: 11522                           Latitude:   32° 35.1' N (  32.58500)
USGS Quad:  ROCKVILLE                       Longitude:  80° 13.7' W ( -80.22830)


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


                         BENCH MARK STAMPING:  OAK NO 2 1933
                         DESIGNATION:          OAK RM 2

MONUMENTATION:           Reference Mark disk                   VM#:        11313
AGENCY:                  US Coast and Geodetic Survey
                         (USC&GS)                              IDB PID#:  CK5142
SETTING CLASSIFICATION:  Concrete post                         OPUS PID:        
LATITUDE:   32° 35.1' N (  32.58500)          LONGITUDE:  80° 13.7' W ( -80.22830)


The bench mark is a disk set in the top of a 0.30 m (1.0 ft) diameter round
concrete post located inland from the beach, 23 m (75 ft) west of the high water
line, 4.27 m (14.0 ft) east of a 0.76 m (2.5 ft) diameter palmetto tree, 4.27 m
(14.0 ft) NW of the center of a group of three palmetto trees which are 0.46 m
(1.5 ft) in diameter, and 8 cm (0.25 ft) above ground level.

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

                                                                                
Station ID: 8667178                         PUBLICATION DATE:  05/23/2003
Name:       POINT OF PINES, N. EDISTO R.                      
            SC
NOAA Chart: 11522                           Latitude:   32° 35.1' N (  32.58500)
USGS Quad:  ROCKVILLE                       Longitude:  80° 13.7' W ( -80.22830)


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


                         BENCH MARK STAMPING:  OAK 1963
                         DESIGNATION:          OAK

MONUMENTATION:           Azimuth Mark disk                     VM#:        11314
AGENCY:                  US Coast and Geodetic Survey
                         (USC&GS)                              IDB PID#:  CK3356
SETTING CLASSIFICATION:  Concrete monument                     OPUS PID:        
LATITUDE:   32° 35.1' N (  32.58500)          LONGITUDE:  80° 13.7' W ( -80.22830)


The bench mark is a disk set in the top of a concrete monument located along the
NW edge of an irrigation ditch and tree-brush line, 1.0 km (0.6 mi) west of the
river bank, 54 m (178 ft) NNW of the center of the road in the tree gap, 4.57 m
(15.0 ft) west of the centerline of a dirt road along the side of the field,
4.21 m (13.8 ft) east of a fence line, 0.3 m (1.0 ft) SSE of a fiberglass
witness post, and at ground level.



                         BENCH MARK STAMPING:  7178 C 1977
                         DESIGNATION:          866 7178 C TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:        11315
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:  CK2513
SETTING CLASSIFICATION:  Galvanized steel rod                  OPUS PID:        
LATITUDE:   32° 35.1' N (  32.58500)          LONGITUDE:  80° 13.6' W ( -80.22670)


The bench mark is a disk located along the beach just above the berm line, 32 m
(105 ft) SE of the NW corner of an old tabby ruin, 28.74 m (94.3 ft) SSE of
bench mark 7178 D 1977, 20.06 m (65.8 ft) SW of a 0.61 m (2.0 ft) diameter
palmetto tree, 6.77 m (22.2 ft) NE of a 0.21 m (0.7 ft) diameter bent oak tree,
and 1.31 m (4.3 ft) east of a metal witness post.  The bench mark is 6 cm (0.2
ft) above the ground, crimped to a galvanized steel rod driven 11.3 m (37 ft) to
refusal, and encased in a 4-inch PVC pipe and a concrete kickblock.

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

                                                                                
Station ID: 8667178                         PUBLICATION DATE:  05/23/2003
Name:       POINT OF PINES, N. EDISTO R.                      
            SC
NOAA Chart: 11522                           Latitude:   32° 35.1' N (  32.58500)
USGS Quad:  ROCKVILLE                       Longitude:  80° 13.7' W ( -80.22830)


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


                         BENCH MARK STAMPING:  7178 D 1977
                         DESIGNATION:          866 7178 D TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:        11316
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:  CK2514
SETTING CLASSIFICATION:  Galvanized steel rod                  OPUS PID:        
LATITUDE:   32° 35.1' N (  32.58500)          LONGITUDE:  80° 13.6' W ( -80.22670)


The bench mark is a disk located along the beach just above the berm line, 28.29
m (92.8 ft) SE of bench mark 7178 E 1977, 26.82 m (88.0 ft) NE of the NW corner
of an old tabby ruin, 13.20 m (43.3 ft) SE of a cluster of 3 live oak trees,
10.36 m (34.0 ft) north of a lone 0.61 m (2.0 ft) diameter palmetto tree and
1.22 m (4.0 ft) ENE of a metal witness post.  The bench mark is 6 cm (0.2 ft)
above the ground, crimped to a galvanized steel rod driven 11.3 m (37 ft) to
refusal, and encased in a PVC pipe and concrete kickblock.

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

                                                                                
Station ID: 8667178                         PUBLICATION DATE:  05/23/2003
Name:       POINT OF PINES, N. EDISTO R.                      
            SC
NOAA Chart: 11522                           Latitude:   32° 35.1' N (  32.58500)
USGS Quad:  ROCKVILLE                       Longitude:  80° 13.7' W ( -80.22830)


                            T I D A L   D A T U M S 


Tidal datums at POINT OF PINES, N. EDISTO R. based on:

     LENGTH OF SERIES:      11 MONTHS
     TIME PERIOD:           June 1978 - April 1979
     TIDAL EPOCH:           1983-2001
     CONTROL TIDE STATION:  8665530 CHARLESTON, COOPER RIVER ENTRANCE


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

     MEAN HIGHER HIGH WATER                     MHHW   =  1.897
     MEAN HIGH WATER                            MHW    =  1.787
     North American Vertical Datum              NAVD88 =  1.067
     MEAN SEA LEVEL                             MSL    =  0.996
     MEAN TIDE LEVEL                            MTL    =  0.925
     MEAN LOW WATER                             MLW    =  0.062
     MEAN LOWER LOW WATER                       MLLW   =  0.000

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MLLW        MHW

     7178 E 1977                                 2.418    0.631
     OAK NO 2 1933                               2.811    1.024
     OAK 1963                                    3.872    2.085
     7178 C 1977                                 2.373    0.586
     7178 D 1977                                 2.324    0.537


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

                                                                                
Station ID: 8667178                         PUBLICATION DATE:  05/23/2003
Name:       POINT OF PINES, N. EDISTO R.                      
            SC
NOAA Chart: 11522                           Latitude:   32° 35.1' N (  32.58500)
USGS Quad:  ROCKVILLE                       Longitude:  80° 13.7' W ( -80.22830)


                             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.