U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
Datums Page                                                        Page  1 of  7

                                                   PUBLICATION DATE:  11/09/1987
Station ID: 8651370                                SUPERCEDED DATE:   04/21/2003
Name:       DUCK, CORPS OF ENGINEERS FIELD RESEARCH FACILITY (
            NORTH CAROLINA
NOAA Chart: 12204                                  Latitude:         36° 11.0' N
USGS Quad:  KITTY HAWK                             Longitude:        75° 44.8' W


To reach the tidal bench marks from the Methodist Church in Duck, proceed north
on State Road 1152 for 1.0 mile (1.6 km) to the U.S. Corps of Engineers Research
Facility.  The bench marks are located on the pier, in the parking lot, and
along the pier access road.  The tide gage and electric tape gage are located on
the offshore end of the pier.


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


                 PRIMARY BENCH MARK STAMPING:  865 1370 B 1977

MONUMENTATION:           Survey Disk                               VM#:      522
AGENCY:                                                            PID#:  FW0688
SETTING CLASSIFICATION:  Galvanized Steel Rod


The bench mark is 222.0 feet (67.7 m) west of the NW inshore piling of the FRF
pier, 200 feet (61 m) west of the centerline of the shore end of the pier, 100
feet (30 m) north of the centerline of the pier access road, and 2 feet    (1 m)
south of a 4x4-inch witness post.  The bench mark is at ground level, crimped to
a galvanized steel rod driven 24 feet (7 m) to refusal, and encased in a 4-inch
PVC pipe and concrete kickblock.



                         BENCH MARK STAMPING:  865 1370 A 1977

MONUMENTATION:           Survey Disk                               VM#:      523
AGENCY:                                                            PID#:  FW0691
SETTING CLASSIFICATION:  Concrete Abutment


The bench mark is set vertically on the south side of the first concrete
abutment of the FRF pier, 0.9 foot (0.3 m) east of the east edge of the concrete
platform of the pier, 4.4 feet (1.3 m) below the edge of the platform, and 3
feet (1 m) above ground level.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  2 of  7

                                                   PUBLICATION DATE:  11/09/1987
Station ID: 8651370                                SUPERCEDED DATE:   04/21/2003
Name:       DUCK, CORPS OF ENGINEERS FIELD RESEARCH FACILITY (
            NORTH CAROLINA
NOAA Chart: 12204                                  Latitude:         36° 11.0' N
USGS Quad:  KITTY HAWK                             Longitude:        75° 44.8' W


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


                         BENCH MARK STAMPING:  865 1370 C 1977

MONUMENTATION:           Survey Disk                               VM#:      524
AGENCY:                                                            PID#:  FW0686
SETTING CLASSIFICATION:  Galvanized Steel Rod


The bench mark is 600 feet (183 m) east of the centerline of State Road 1152,
100 feet (30 m) north of the centerline of the pier access road, and 2 feet   
(1 m) south of a 4x4-inch witness post.  The bench mark is at ground level,
crimped to a galvanized steel rod driven 32 feet (10 m) to refusal, and encased
in a 4-inch PVC pipe and concrete kickblock.



                         BENCH MARK STAMPING:  865 1370 D 1977

MONUMENTATION:           Survey Disk                               VM#:      525
AGENCY:                                                            PID#:  FW0685
SETTING CLASSIFICATION:  Galvanized Steel Rod


The bench mark is 100 feet (30 m) east of the centerline of State Road 1152, 100
feet (30 m) north of the centerline of the pier access road, and 2 feet    (1 m)
south of a 4x4-inch witness post.  The bench mark is at ground level, crimped to
a galvanized steel rod driven 24 feet (7 m) 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  7

                                                   PUBLICATION DATE:  11/09/1987
Station ID: 8651370                                SUPERCEDED DATE:   04/21/2003
Name:       DUCK, CORPS OF ENGINEERS FIELD RESEARCH FACILITY (
            NORTH CAROLINA
NOAA Chart: 12204                                  Latitude:         36° 11.0' N
USGS Quad:  KITTY HAWK                             Longitude:        75° 44.8' W


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


                         BENCH MARK STAMPING:  1370 E 1979

MONUMENTATION:           Survey Disk                               VM#:      526
AGENCY:                                                            PID#:  FW0683
SETTING CLASSIFICATION:  Copper-clad Steel Rod


The bench mark is 72.7 feet (22.2 m) east of the centerline of State Road 1152,
66.2 feet (20.2 m) south of the centerline of the pier access road, and 46.8
feet (14.3 m) ESE of a fire hydrant at the junction of State Road 1152 and the
access road.  The bench mark is 0.1 foot (0.03 m) above ground level, crimped to
a copper-clad steel rod driven 24 feet (7 m) to refusal, and encased in a 4-inch
PVC pipe and concrete kickblock.



                         BENCH MARK STAMPING:  1370 F 1979

MONUMENTATION:           Survey Disk                               VM#:      527
AGENCY:                                                            PID#:  FW0684
SETTING CLASSIFICATION:  Copper-clad Steel Rod


The bench mark is located 175.0 feet (53.3 m) west of the centerline of State
Road 1152, 52 feet (16 m) east of Currituck Sound shoreline, 9.8 feet (3.0 m) NW
of utility pole #440, 3.2 feet (1.0 m) SW of a guy wire anchor for utility pole
#440, and 1.2 feet (0.4 m) south of a 4x4-inch witness post.  The bench mark is
0.4 foot (0.1 m) above ground level, crimped to a copper-clad steel rod driven
23 feet (7 m) 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  7

                                                   PUBLICATION DATE:  11/09/1987
Station ID: 8651370                                SUPERCEDED DATE:   04/21/2003
Name:       DUCK, CORPS OF ENGINEERS FIELD RESEARCH FACILITY (
            NORTH CAROLINA
NOAA Chart: 12204                                  Latitude:         36° 11.0' N
USGS Quad:  KITTY HAWK                             Longitude:        75° 44.8' W


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


                         BENCH MARK STAMPING:  1370 G 1980

MONUMENTATION:           Survey Disk                               VM#:      528
AGENCY:                                                            PID#:  FW0692
SETTING CLASSIFICATION:  Concrete Deck


The bench mark is set flush in the SE corner of the concrete platform leading to
the FRF pier, 78.4 feet (23.9 m) east of the west face of the platform, 56.4
feet (17.2 m) south of the centerline of the platform, 25.9 feet (7.9 m) SE of
the SE corner of the office building on the platform, and 1.5 feet    (0.5 m)
north of the south face of the platform.



                         BENCH MARK STAMPING:  1370 H 1980

MONUMENTATION:           Survey Disk                               VM#:      529
AGENCY:                                                            PID#:  FW0689
SETTING CLASSIFICATION:  Concrete Foundation


The bench mark is set flush in the concrete platform leading to the FRF pier,
72.6 feet (22.1 m) north of the centerline of the platform, 35.5 feet (10.8 m)
NE of the NE corner of the office building on the platform, 1.6 feet (0.5 m)
west of the east face of the platform, and 1.6 feet (0.5 m) south of the north
face of the platform.



                         BENCH MARK STAMPING:  1370 J 1980

MONUMENTATION:           Survey Disk                               VM#:      530
AGENCY:                                                            PID#:  FW0687
SETTING CLASSIFICATION:  Concrete Ramp


The bench mark is set flush in the SE corner of a footing on the south side of
an asphalt ramp leading to a platform on the north side of the FRF pier, 58.5
feet (17.8 m) north of the centerline of the pier access road, 9.0 feet    (2.7
m) east of the west end of the footing, 8.7 feet (2.7 m) south of the centerline
of the asphalt ramp, and 3.8 feet (1.2 m) above ground level.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  5 of  7

                                                   PUBLICATION DATE:  11/09/1987
Station ID: 8651370                                SUPERCEDED DATE:   04/21/2003
Name:       DUCK, CORPS OF ENGINEERS FIELD RESEARCH FACILITY (
            NORTH CAROLINA
NOAA Chart: 12204                                  Latitude:         36° 11.0' N
USGS Quad:  KITTY HAWK                             Longitude:        75° 44.8' W


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


                         BENCH MARK STAMPING:  1370 K 1980

MONUMENTATION:           Survey Disk                               VM#:      531
AGENCY:                                                            PID#:  FW0690
SETTING CLASSIFICATION:  Concrete Pier Decking


The bench mark is set flush in the concrete decking on the south side of the FRF
pier at the wind tower, 1278 feet (390 m) ESE of the inshore end of the pier,
562 feet (171 m) west of the offshore end of the pier, 16.2 feet (4.9 m) south
of the north face of the pier, 2.7 feet (0.8 m) north of the south face of the
pier, and 1 foot (0.3 m) north of the northernmost leg of the tower.



                         BENCH MARK STAMPING:  # 64

MONUMENTATION:           Survey Disk                               VM#:      532
AGENCY:                                                            PID:         
SETTING CLASSIFICATION:  Concrete Monument


The bench mark is set in the top of a concrete monument west of State Road 1152
and the pier access road, south of a sand trail, 140 feet (43 m) south of a
VEPCO utility pole on the south side of the sand trail, 124 feet (38 m) east of
a VEPCO utility pole in Currituck Sound, and 30 feet (9 m) east of a VEPCO
utility pole.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  6 of  7

                                                   PUBLICATION DATE:  11/09/1987
Station ID: 8651370                                SUPERCEDED DATE:   04/21/2003
Name:       DUCK, CORPS OF ENGINEERS FIELD RESEARCH FACILITY (
            NORTH CAROLINA
NOAA Chart: 12204                                  Latitude:         36° 11.0' N
USGS Quad:  KITTY HAWK                             Longitude:        75° 44.8' W


                            T I D A L   D A T U M S 


Tidal datums at DUCK, CORPS OF ENGINEERS FIELD RESEARCH FACILITY ( based on:

     LENGTH OF SERIES:      8 YEARS
     TIME PERIOD:           1979-1986
     TIDAL EPOCH:           1960-1978
     CONTROL TIDE STATION:  8638610 HAMPTON ROADS, VA


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

     HIGHEST OBSERVED WATER LEVEL (11/13/1981)         =   6.50
     MEAN HIGHER HIGH WATER                     MHHW   =   3.75
     MEAN HIGH WATER                            MHW    =   3.43
     MEAN TIDE LEVEL                            MTL    =   1.79
   * NATIONAL GEODETIC VERTICAL DATUM           NGVD29 =   1.60
     MEAN LOW WATER                             MLW    =   0.15
     MEAN LOWER LOW WATER                       MLLW   =   0.00
     LOWEST  OBSERVED WATER LEVEL (03/16/1980)         =  -2.29

   * NGVD reference based on elevations published in Quad 360753, 1982, and NOS
     leveling of 1986. 
North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In FEET above:

     Stamping or Designation                    MLLW        MHW

     865 1370 B 1977                            14.80     11.37
     865 1370 A 1977                            22.45     19.02
     865 1370 C 1977                            21.03     17.60
     865 1370 D 1977                            10.00      6.57
     1370 E 1979                                 7.53      4.10
     1370 F 1979                                 7.50      4.07
     1370 G 1980                                26.80     23.37
     1370 H 1980                                26.75     23.32
     1370 J 1980                                19.73     16.30
     1370 K 1980                                27.02     23.59
     # 64                                        5.84      2.41


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

                                                   PUBLICATION DATE:  11/09/1987
Station ID: 8651370                                SUPERCEDED DATE:   04/21/2003
Name:       DUCK, CORPS OF ENGINEERS FIELD RESEARCH FACILITY (
            NORTH CAROLINA
NOAA Chart: 12204                                  Latitude:         36° 11.0' N
USGS Quad:  KITTY HAWK                             Longitude:        75° 44.8' W


                             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 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.