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

                                                                                
Station ID: 8534393                         PUBLICATION DATE:  05/12/2004
Name:       MAIN MARSH THOROFARE                              
            NJ
NOAA Chart: 12316                           Latitude:   39° 28.7' N (  39.47830)
USGS Quad:  OCEANVILLE                      Longitude:  74° 23.0' W ( -74.38330)


To reach the tidal bench marks from Oyster Creek, proceed 4.0 km (2.5 mi) SE
along the south shore of Great Bay to the Intracoastal Waterway of Main Marsh
Thorofare, then proceed 0.6 km (0.4 mi) SW along the thorofare to a small creek
on the west bank of Main Marsh.  The bench marks are located along the shore of
the small creek.  The tide gage and staff were located on a wooden platform on
the shore of Main Marsh Thorofare.


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


                 PRIMARY BENCH MARK STAMPING:  4393 D 1977
                         DESIGNATION:          853 4393 D TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:         2683
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Galvanized steel rod                  OPUS PID:        
LATITUDE:   39° 28.7' N (  39.47830)          LONGITUDE:  74° 23.0' W ( -74.38330)


The primary bench mark is a disk located 53 m (175 ft) SE of bench mark BM 4
1971, 17.68 m (58.0 ft) east of the east bank of the small creek on the west
bank of Main Marsh Thorofare, 16.15 m (53.0 ft) SW of bench mark Z 55 1961,
10.49 m (34.4 ft) SW of a wildlife refuge sign, and 4.57 m (15.0 ft) west of the
top of the bank of the Thorofare.  The bench mark is set 0.15 m (0.5 ft) above
ground level, crimped to the top of a galvanized steel rod driven 15.2 m (50 ft)
to refusal, and encased in a PVC pipe and a concrete kickblock.

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

                                                                                
Station ID: 8534393                         PUBLICATION DATE:  05/12/2004
Name:       MAIN MARSH THOROFARE                              
            NJ
NOAA Chart: 12316                           Latitude:   39° 28.7' N (  39.47830)
USGS Quad:  OCEANVILLE                      Longitude:  74° 23.0' W ( -74.38330)


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


                         BENCH MARK STAMPING:  BM 4 1971
                         DESIGNATION:          853 4393 TIDAL 4

MONUMENTATION:           Tidal Station disk                    VM#:         2681
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Shallow set pipe                      OPUS PID:        
LATITUDE:   39° 28.7' N (  39.47830)          LONGITUDE:  74° 23.0' W ( -74.38330)


The bench mark is a disk located on the west bank of Main Marsh Thorofare
halfway from the entrance to Great Bay, 53 m (175 ft) NW of bench mark 4393 D
1977, 18 m (60 ft) south of the bend of a creek which extends due west from the
thorofare, 8 m (25 ft) south of a large piling and approximately on range with
the south Brigantine water tower.  The bench mark is set 0.15 m (0.5 ft) above
ground level, crimped to the top of a pipe driven 3.0 m (10 ft) into the marsh.



                         BENCH MARK STAMPING:  BM 6 1971
                         DESIGNATION:          853 4393 TIDAL 6

MONUMENTATION:           Tidal Station disk                    VM#:         2682
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Unspecified                           OPUS PID:        
LATITUDE:   39° 28.7' N (  39.47830)          LONGITUDE:  74° 23.0' W ( -74.38330)


The bench mark is a disk located on the west bank of Main Marsh Thorofare near
the entrance to a small creek, 53 m (175 ft) NW of bench mark BM 4 1971, 40 m
(130 ft) west of bench mark Z 55 1961, 30 m (100 ft) WNW from the bend in the
small creek at the point where the creek runs from west to south.

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

                                                                                
Station ID: 8534393                         PUBLICATION DATE:  05/12/2004
Name:       MAIN MARSH THOROFARE                              
            NJ
NOAA Chart: 12316                           Latitude:   39° 28.7' N (  39.47830)
USGS Quad:  OCEANVILLE                      Longitude:  74° 23.0' W ( -74.38330)


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


                         BENCH MARK STAMPING:  4393 E 1977
                         DESIGNATION:          853 4393 E TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:         2684
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Galvanized steel rod                  OPUS PID:        
LATITUDE:   39° 28.4' N (  39.47330)          LONGITUDE:  74° 23.0' W ( -74.38330)


The bench mark is a disk located 51.21 m (168.0 ft) south of bench mark 4393 D
1977, 18.29 m (60.0 ft) SE of the east bank of a small creek, and 12.19 m (40.0
ft) NW of the top of bank of the Thorofare.  The bench mark is 0.30 m (1.0 ft)
above ground level, crimped to the top of a galvanized steel rod driven 15.24 m
(50.0 ft) to refusal, and encased in a 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: 8534393                         PUBLICATION DATE:  05/12/2004
Name:       MAIN MARSH THOROFARE                              
            NJ
NOAA Chart: 12316                           Latitude:   39° 28.7' N (  39.47830)
USGS Quad:  OCEANVILLE                      Longitude:  74° 23.0' W ( -74.38330)


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


                         BENCH MARK STAMPING:  Z 55 1961
                         DESIGNATION:          Z 55

MONUMENTATION:           Bench Mark disk                       VM#:        12413
AGENCY:                  US Coast & Geodetic Survey
                         (USC&GS)                                 IDB PID#:  JU0280
SETTING CLASSIFICATION:  Metal pipe                            OPUS PID:        
LATITUDE:   39° 28.8' N (  39.48000)          LONGITUDE:  74° 23.0' W ( -74.38330)


The bench mark is a disk located 27 m (90 ft) west of the west bank of Main
Marsh Thorofare, 27 m (88 ft) north of north bank of the creek, and 0.12 m (0.4
ft) above ground level.  The bench mark is set on top of a 3-inch galvanized
iron pipe.

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

                                                                                
Station ID: 8534393                         PUBLICATION DATE:  05/12/2004
Name:       MAIN MARSH THOROFARE                              
            NJ
NOAA Chart: 12316                           Latitude:   39° 28.7' N (  39.47830)
USGS Quad:  OCEANVILLE                      Longitude:  74° 23.0' W ( -74.38330)


                            T I D A L   D A T U M S 


Tidal datums at MAIN MARSH THOROFARE based on:

     LENGTH OF SERIES:      8 MONTHS
     TIME PERIOD:           April 1978 - November 1978
     TIDAL EPOCH:           1983-2001
     CONTROL TIDE STATION:  8557380 LEWES, FT. MILES


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

     MEAN HIGHER HIGH WATER                     MHHW   =  1.123
     MEAN HIGH WATER                            MHW    =  1.018
     MEAN TIDE LEVEL                            MTL    =  0.529
     MEAN SEA LEVEL                             MSL    =  0.521
     MEAN LOW WATER                             MLW    =  0.040
     MEAN LOWER LOW WATER                       MLLW   =  0.000

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MLLW        MHW

     4393 D 1977                                 1.154    0.136
     BM 4 1971                                   1.207    0.189
     BM 6 1971                                   1.223    0.205
     4393 E 1977                                 1.270    0.252
     Z 55 1961                                   1.260    0.242


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

                                                                                
Station ID: 8534393                         PUBLICATION DATE:  05/12/2004
Name:       MAIN MARSH THOROFARE                              
            NJ
NOAA Chart: 12316                           Latitude:   39° 28.7' N (  39.47830)
USGS Quad:  OCEANVILLE                      Longitude:  74° 23.0' W ( -74.38330)


                             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.