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

                                                                                
Station ID: 8662405                         PUBLICATION DATE:  06/16/2003
Name:       JAMESTOWN BRIDGE, SANTEE RIVER                    
            SC
NOAA Chart: 11531                           Latitude:   33° 18.3' N (  33.30500)
USGS Quad:  JAMESTOWN                       Longitude:  79° 40.7' W ( -79.67830)


To reach the tidal bench marks from the intersection of U.S. Highway 17A and
State Highway 41 at Jamestown, proceed north on U.S. Highway 17A for 2.4 km (1.5
mi) to the W.H. Andrews Memorial Bridge over the Santee River.  The bench marks
are on the south end of the bridge, and along a dirt road to the SE of U.S.
Highway 17A, just south of the bridge.  The tide station was located on the SE
end of the bridge.


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


                 PRIMARY BENCH MARK STAMPING:  2405 A 1976
                         DESIGNATION:          866 2405 A TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:         3927
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:  DD1149
SETTING CLASSIFICATION:  Concrete bridge abutment              OPUS PID:        
LATITUDE:   33° 18.3' N (  33.30500)          LONGITUDE:  79° 40.7' W ( -79.67830)


The primary bench mark is a disk set in the SW concrete bridge abutment, 4.39 m
(14.4 ft) NE of the centerline of the bridge, 0.40 m (1.3 ft) ESE of the bridge
rail, 0.15 m (0.5 ft) NNW of the end of the bridge, and 0.3 m (1.0 ft) above
highway level.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  2 of  6

                                                                                
Station ID: 8662405                         PUBLICATION DATE:  06/16/2003
Name:       JAMESTOWN BRIDGE, SANTEE RIVER                    
            SC
NOAA Chart: 11531                           Latitude:   33° 18.3' N (  33.30500)
USGS Quad:  JAMESTOWN                       Longitude:  79° 40.7' W ( -79.67830)


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


                         BENCH MARK STAMPING:  2405 B 1976
                         DESIGNATION:          866 2405 B TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:         3928
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:  DD1150
SETTING CLASSIFICATION:  Concrete bridge abutment              OPUS PID:        
LATITUDE:   33° 18.3' N (  33.30500)          LONGITUDE:  79° 40.7' W ( -79.67830)


The bench mark is a disk set flush in the SE concrete bridge abutment, 8.78 m
(28.8 ft) SE of 2405 A 1976, 4.39 m (14.4 ft) SW of the centerline of the
bridge, 2.13 m (7.0 ft) NNE of the bridge, 0.49 m (1.6 ft) ENE of the right
bridge rail, 0.18 m (0.6 ft) NNE of the end of the bridge abutment, and 0.3 m
(1.0 ft) above the highway.



                         BENCH MARK STAMPING:  2405 C 1976
                         DESIGNATION:          866 2405 C TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:         3929
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:  DD1153
SETTING CLASSIFICATION:  Copper-clad steel rod                 OPUS PID:        
LATITUDE:   33° 18.2' N (  33.30330)          LONGITUDE:  79° 40.7' W ( -79.67830)


The bench mark is a disk located in the treeline at the SE edge of the dirt road
paralleling the SE side of the highway, 91 m (299 ft) east of bench mark 2405 G
1976, 37.92 m (124.4 ft) SSW of the SE corner of the bridge, 16.12 m (52.9 ft)
SE of the centerline of the highway, 2.99 m (9.8 ft) north of a 1 m (2 ft)
diameter pine tree, 2.13 m (7.0 ft) SSE of the center of the dirt road, and 0.46
m (1.5 ft) NNE of a metal witness post.  The bench mark is set about 4 m (12 ft)
below the highway, crimped to the top of a copper-clad steel rod driven 4.9 m
(16 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  3 of  6

                                                                                
Station ID: 8662405                         PUBLICATION DATE:  06/16/2003
Name:       JAMESTOWN BRIDGE, SANTEE RIVER                    
            SC
NOAA Chart: 11531                           Latitude:   33° 18.3' N (  33.30500)
USGS Quad:  JAMESTOWN                       Longitude:  79° 40.7' W ( -79.67830)


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


                         BENCH MARK STAMPING:  2405 E 1976
                         DESIGNATION:          866 2405 E TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:         3931
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:  DD1151
SETTING CLASSIFICATION:  Copper-clad steel rod                 OPUS PID:        
LATITUDE:   33° 18.0' N (  33.30000)          LONGITUDE:  79° 40.9' W ( -79.68170)


The bench mark is a disk located between the tree line and Highway 17A at its
intersection with the dirt road leading to the boat ramp just SE of the bridge,
88 m (290 ft) west of 2405 G 1976, 9.63 m (31.6 ft) SE of the centerline of the
highway, 1.83 m (6.0 ft) east of the center of the dirt road leading back from
the boat ramp, and 0.70 m (2.3 ft) east of a metal witness post and sign.  The
bench mark is set 1.49 m (4.9 ft) below the highway, crimped to the top of a
copper-clad steel rod driven 4.9 m (16 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  4 of  6

                                                                                
Station ID: 8662405                         PUBLICATION DATE:  06/16/2003
Name:       JAMESTOWN BRIDGE, SANTEE RIVER                    
            SC
NOAA Chart: 11531                           Latitude:   33° 18.3' N (  33.30500)
USGS Quad:  JAMESTOWN                       Longitude:  79° 40.7' W ( -79.67830)


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


                         BENCH MARK STAMPING:  2405 G 1982
                         DESIGNATION:          866 2405 G TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:         3932
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:  DD1152
SETTING CLASSIFICATION:  Copper-clad steel rod                 OPUS PID:        
LATITUDE:   33° 18.1' N (  33.30170)          LONGITUDE:  79° 40.8' W ( -79.68000)


The bench mark is a disk located near a lone 1.28 m (4.2 ft) diameter pine tree
in the treeline at the SE edge of the dirt road paralleling the SE side of the
highway, 14.72 m (48.3 ft) SE of the centerline of the highway, 5.58 m (18.3 ft)
north of a 1 m (3 ft) diameter pine tree, 3.14 m (10.3 ft) WSW of the 1.28 m
(4.2 ft) diameter pine tree, 2.29 m (7.5 ft) SE of the center of the dirt road,
and 0.88 m (2.9 ft) north of a witness post and sign.  The bench mark is set
about 3 m (10 ft) below the highway, crimped to the top of a copper-clad steel
rod driven 7.3 m (24 ft) to refusal, and encased in a 5-inch PVC pipe and
concrete kickblock.

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

                                                                                
Station ID: 8662405                         PUBLICATION DATE:  06/16/2003
Name:       JAMESTOWN BRIDGE, SANTEE RIVER                    
            SC
NOAA Chart: 11531                           Latitude:   33° 18.3' N (  33.30500)
USGS Quad:  JAMESTOWN                       Longitude:  79° 40.7' W ( -79.67830)


                            T I D A L   D A T U M S 


Tidal datums at JAMESTOWN BRIDGE, SANTEE RIVER based on:

     LENGTH OF SERIES:      4 MONTHS
     TIME PERIOD:           May 1977 - August 1977
     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   =  0.406
     MEAN HIGH WATER                            MHW    =  0.361
     MEAN TIDE LEVEL                            MTL    =  0.191
     MEAN SEA LEVEL                             MSL    =  0.179
     MEAN LOW WATER                             MLW    =  0.020
     MEAN LOWER LOW WATER                       MLLW   =  0.000
     North American Vertical Datum              NAVD88 = -0.135

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MLLW        MHW

     2405 A 1976                                12.502   12.141
     2405 B 1976                                12.503   12.142
     2405 C 1976                                 8.244    7.883
     2405 E 1976                                 9.121    8.760
     2405 G 1982                                 7.709    7.348


Foot Notes:

Note:The tidal signal is masked at this station during periods of high river
level.

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

                                                                                
Station ID: 8662405                         PUBLICATION DATE:  06/16/2003
Name:       JAMESTOWN BRIDGE, SANTEE RIVER                    
            SC
NOAA Chart: 11531                           Latitude:   33° 18.3' N (  33.30500)
USGS Quad:  JAMESTOWN                       Longitude:  79° 40.7' W ( -79.67830)


                             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.