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

                                                                                
Station ID: 8630308                         PUBLICATION DATE:  07/12/2004
Name:       CHINCOTEAGUE CHANNEL, SOUTH END                   
            VA
NOAA Chart: 12211                           Latitude:   37° 54.4' N (  37.90670)
USGS Quad:  CHINCOTEAGUE EAST               Longitude:  75° 24.3' W ( -75.40500)


To reach the tidal bench marks from Chincoteague at the junction of Main Street
and State Highway 175, proceed south along Main Street (State Road 2114) for 3.8
km (2.4 mi) to Mr. Minnicks lot, on the west side of Main Street.  The tide gage
and staff were located on the north side of the southernmost of two boat slips
at Mr. Minnicks lot.


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


                 PRIMARY BENCH MARK STAMPING:  863 0308 B 1977
                         DESIGNATION:          863 0308 B TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:         3260
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Concrete monument                     OPUS PID:        
LATITUDE:   37° 54.4' N (  37.90670)          LONGITUDE:  75° 24.3' W ( -75.40500)


The primary bench mark is a disk set in a concrete monument, 41.61 m (136.5 ft)
SE of bench mark 863 0308 A 1977, 22.25 m (73.0 ft) NW of the north corner of
Mr. Minnicks trailer, 0.67 m (2.2 ft) NE of the east corner of a block
foundation and at ground level.



                         BENCH MARK STAMPING:  863 0308 A 1977
                         DESIGNATION:          863 0308 A TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:         3259
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Concrete monument                     OPUS PID:        
LATITUDE:   37° 54.4' N (  37.90670)          LONGITUDE:  75° 24.3' W ( -75.40500)


The bench mark is a disk set in a concrete monument in the back of Mr. Minnick's
lot near the north line, 41.61 m (136.5 ft) NW of bench mark 863 0308 B 1977,
7.41 m (24.3 ft) east of the north corner of a shop, 6.46 m (21.2 ft) NE of the
east corner of the shop and at ground level.

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

                                                                                
Station ID: 8630308                         PUBLICATION DATE:  07/12/2004
Name:       CHINCOTEAGUE CHANNEL, SOUTH END                   
            VA
NOAA Chart: 12211                           Latitude:   37° 54.4' N (  37.90670)
USGS Quad:  CHINCOTEAGUE EAST               Longitude:  75° 24.3' W ( -75.40500)


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


                         BENCH MARK STAMPING:  863 0308 C 1977
                         DESIGNATION:          863 0308 C TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:         3261
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Concrete monument                     OPUS PID#: BBDY44
LATITUDE:   37° 54.4' N (  37.90670)          LONGITUDE:  75° 24.3' W ( -75.40500)


The bench mark is a disk set in concrete, near the southeastern part of a large
parking lot, 58.06 m (190.5 ft) NE of the east corner of Mr. Minnick's trailer,
48 m (156 ft) NW of the centerline of the road, 4.72 m (15.5 ft) SE of a power
pole and at ground level.

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

                                                                                
Station ID: 8630308                         PUBLICATION DATE:  07/12/2004
Name:       CHINCOTEAGUE CHANNEL, SOUTH END                   
            VA
NOAA Chart: 12211                           Latitude:   37° 54.4' N (  37.90670)
USGS Quad:  CHINCOTEAGUE EAST               Longitude:  75° 24.3' W ( -75.40500)


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


                         BENCH MARK STAMPING:  NO 2 1962
                         DESIGNATION:          TIDAL 2 STA 5

MONUMENTATION:           Tidal Station disk                    VM#:         3262
AGENCY:                  US Coast & Geodetic Survey
                         (USC&GS)                                 IDB PID#:  FW0142
SETTING CLASSIFICATION:  Concrete-filled terra cotta pipe      OPUS PID:        
LATITUDE:   37° 54.3' N (  37.90500)          LONGITUDE:  75° 24.4' W ( -75.40670)


The bench mark is a disk set in the top of a concrete filled terra cotta pipe,
70 m (230 ft) east of the centerline of Main Street at a side road entrance, 65
m (212 ft) east of power pole ESPSC of Virginia 17 with transformer, 26 m (86
ft) SSE of the fourth USCG telephone pole, 19 m (63 ft) NNW of the third USCG
telephone pole and 0.15 m (0.5 ft) above ground level.  NOTE: For the complete
leveling record for this mark, see station 863-0316, Harbor of Refuge.

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

                                                                                
Station ID: 8630308                         PUBLICATION DATE:  07/12/2004
Name:       CHINCOTEAGUE CHANNEL, SOUTH END                   
            VA
NOAA Chart: 12211                           Latitude:   37° 54.4' N (  37.90670)
USGS Quad:  CHINCOTEAGUE EAST               Longitude:  75° 24.3' W ( -75.40500)


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


                         BENCH MARK STAMPING:  NO 3 1962
                         DESIGNATION:          TIDAL 3 STA 5

MONUMENTATION:           Tidal Station disk                    VM#:         3263
AGENCY:                  US Coast & Geodetic Survey
                         (USC&GS)                                 IDB PID#:  FW0143
SETTING CLASSIFICATION:  Concrete-filled terra cotta pipe      OPUS PID:        
LATITUDE:   37° 54.3' N (  37.90500)          LONGITUDE:  75° 24.4' W ( -75.40670)


The bench mark is a disk set in the top of a concrete filled terra cotta pipe,
69 m (225 ft) NNW of bench mark No 2 1962, 43 m (140 ft) SE of power pole ESPSC
of Virginia (the first pole north of the pole with a transformer attached), 38 m
(126 ft) west of the fifth USCG telephone pole from the south end of the island
and 30 m (100 ft) north of the middle of three one-room cottages.  NOTE: For the
complete leveling record for this mark, see station 863-0316, Harbor of Refuge.

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

                                                                                
Station ID: 8630308                         PUBLICATION DATE:  07/12/2004
Name:       CHINCOTEAGUE CHANNEL, SOUTH END                   
            VA
NOAA Chart: 12211                           Latitude:   37° 54.4' N (  37.90670)
USGS Quad:  CHINCOTEAGUE EAST               Longitude:  75° 24.3' W ( -75.40500)


                            T I D A L   D A T U M S 


Tidal datums at CHINCOTEAGUE CHANNEL, SOUTH END based on:

     LENGTH OF SERIES:      3 MONTHS
     TIME PERIOD:           June 1977 - August 1977
     TIDAL EPOCH:           1983-2001
     CONTROL TIDE STATION:  8630249 CHINCOTEAGUE, USCG STATION


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

     MEAN HIGHER HIGH WATER                     MHHW   =  0.758
     MEAN HIGH WATER                            MHW    =  0.691
     North American Vertical Datum              NAVD88 =  0.401
     MEAN TIDE LEVEL                            MTL    =  0.362
     MEAN SEA LEVEL                             MSL    =  0.359
     MEAN LOW WATER                             MLW    =  0.033
     MEAN LOWER LOW WATER                       MLLW   =  0.000

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MLLW        MHW

     863 0308 B 1977                             1.380    0.689
     863 0308 A 1977                             1.564    0.873
     863 0308 C 1977                             1.606    0.915
     NO 2 1962                                   1.427    0.736
     NO 3 1962                                   1.252    0.561


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

                                                                                
Station ID: 8630308                         PUBLICATION DATE:  07/12/2004
Name:       CHINCOTEAGUE CHANNEL, SOUTH END                   
            VA
NOAA Chart: 12211                           Latitude:   37° 54.4' N (  37.90670)
USGS Quad:  CHINCOTEAGUE EAST               Longitude:  75° 24.3' W ( -75.40500)


                             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.