Superseded Bench Mark Sheet for 8631044, Wachapreague VA

Present Epoch

Printable version

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

                                                   PUBLICATION DATE:  07/06/1987
Station ID: 8631044                                SUPERCEDED DATE:   04/21/2003
Name:       WACHAPREAGUE, WACHAPREAGUE CHANNEL                
            VIRGINIA
NOAA Chart: 12210                                  Latitude:         37° 36.4' N
USGS Quad:  WACHAPREAGUE                           Longitude:        75° 41.2' W


To reach the tidal bench marks from intersection of US Highway 13 and State
Route 180 in Keller, proceed east on State Route 180 4.4 miles (7.1 km) to a T
intersection with Atlantic Avenue (County Road 1701), continue north on Atlantic
Avenue 0.4 mile (0.6 km) to the Virginia Institute of Marine Sciences (VIMS),
Eastern Shore Laboratory.  The bench marks are located on VIMS property.  The
tide gage and staff were located on the salt water pump house pier, ESE of the
north end of Atlantic Avenue.


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


                 PRIMARY BENCH MARK STAMPING:  1044 B 1978

MONUMENTATION:           Survey Disk                               VM#:      469
AGENCY:                                                            PID:         
SETTING CLASSIFICATION:  Brick Wall


The bench mark is set vertically in the brick main laboratory building VIMS, at
the SW corner of the intersection of Liberty Street and Atlantic Avenue, 39 feet
(12 m) WNW of the centerline of Atlantic Avenue, 1.4 feet (0.4 m) NNE of the SE
corner of the building and 3.5 feet (1.1 m) above the pavement.



                         BENCH MARK STAMPING:  1044 A 1978

MONUMENTATION:           Survey Disk                               VM#:      470
AGENCY:                                                            PID:         
SETTING CLASSIFICATION:  Concrete Boat Ramp


The bench mark is set flush on the NE side of the boat ramp. 100.9 feet (30.8 m)
SE of the centerline of Atlantic Avenue (County Road 1701), 55.7 feet (17.0 m)
SW of the SE corner of Quonset hut lab building, 46.5 feet (14.2 m) WSW of the
SE corner of the bulkhead at the boat ramp, 27.5 feet (8.9 m) NNW of a Delmarva
Power & Light pole # DP&L 44151 65595, 7.5 feet (2.29 m) NE of the western
corner of the boat ramp.

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

                                                   PUBLICATION DATE:  07/06/1987
Station ID: 8631044                                SUPERCEDED DATE:   04/21/2003
Name:       WACHAPREAGUE, WACHAPREAGUE CHANNEL                
            VIRGINIA
NOAA Chart: 12210                                  Latitude:         37° 36.4' N
USGS Quad:  WACHAPREAGUE                           Longitude:        75° 41.2' W


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


                         BENCH MARK STAMPING:  1044 C 1978

MONUMENTATION:           Survey Disk                               VM#:      471
AGENCY:                                                            PID:         
SETTING CLASSIFICATION:  Concrete Monument


The bench mark is set flush in a concrete monument 41.5 feet (12.7 m) NNW of
Atlantic Avenue, 33.5 feet (10.2 m) NNE of the centerline of Riverview Avenue, 3
feet (1 m) east of a 2 x 3 foot (1 x 1 m) white box weather station, and level
with the ground.



                         BENCH MARK STAMPING:  1044 D 1978

MONUMENTATION:           Survey Disk                               VM#:      472
AGENCY:                                                            PID:         
SETTING CLASSIFICATION:  Concrete Monument


The bench mark is set flush in top of a concrete monument located on the north
side of Liberty Street, off the SE corner of a green absestos shingle house,
50.7 feet (15.4 m) NW of a Delmarva Power and Light pole, # 44144 65615, 32.5
feet (9.9 m) NE of the centerline of Liberty Street, 30.8 feet (9.4 m) NNE of
the centerline of Atlantic Avenue, 30.5 feet (9.3 m) NW of the NW corner of a
2.7 x 5.0-foot (0.8 x 1.5 m)concrete saltwater sump, 4.5 feet (1.4 m) ESE of the
SW corner of the dormitory building, and level with the ground.

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

                                                   PUBLICATION DATE:  07/06/1987
Station ID: 8631044                                SUPERCEDED DATE:   04/21/2003
Name:       WACHAPREAGUE, WACHAPREAGUE CHANNEL                
            VIRGINIA
NOAA Chart: 12210                                  Latitude:         37° 36.4' N
USGS Quad:  WACHAPREAGUE                           Longitude:        75° 41.2' W


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


                         BENCH MARK STAMPING:  1044 E 1978

MONUMENTATION:           Survey Disk                               VM#:      473
AGENCY:                                                            PID:         
SETTING CLASSIFICATION:  Concrete Monument


The bench mark is set flush in top of a concrete monument located off the NW
corner of a brick pump house, 90.7 feet (27.9 m) SW of the centerline of Liberty
Street (County Road 1711), 45.5 feet (13.9 m) west of the western corner of the
main laboratory building, 31.3 feet (9.5 m) north of the northern corner of a
barn type garage building, 2.2 feet (0.7 m) north of the northern corner of an 9
x 9-foot(3 x3 m) square brick pumphouse, and 0.1 foot (0.1 m) below ground
level.



                         BENCH MARK STAMPING:  1044 F 1981

MONUMENTATION:           Survey Disk                               VM#:      474
AGENCY:                                                            PID:         
SETTING CLASSIFICATION:  Stainless Steel Rod


The bench mark is located on the east side of Atlantic Avenue near the
intersection with Liberty Street, 70.5 feet (21.5 m) east of the NE corner of
the brick laboratory building, 57.4 feet (17.5 m) north of the NW corner of a
fiberglass Quonset hut building, 25.5 feet (7.8 m) ESE of the centerline of
Atlantic Avenue, 13.0 feet (4.0 m) SSW of the extended centerline of Liberty
Street, and 2.0 feet (0.6 m) ESE of power pole # 29L/317M.  The bench mark is
level with the ground, crimped on the top of a stainless steel rod driven 32
feet (10 m), to refusal, and encased in a 6-inch PVC pipe and concrete kick
block.

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

                                                   PUBLICATION DATE:  07/06/1987
Station ID: 8631044                                SUPERCEDED DATE:   04/21/2003
Name:       WACHAPREAGUE, WACHAPREAGUE CHANNEL                
            VIRGINIA
NOAA Chart: 12210                                  Latitude:         37° 36.4' N
USGS Quad:  WACHAPREAGUE                           Longitude:        75° 41.2' W


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


                         BENCH MARK STAMPING:  1044 G 1981

MONUMENTATION:           Survey Disk                               VM#:      475
AGENCY:                                                            PID:         
SETTING CLASSIFICATION:  Stainless Steel Rod


The bench mark is located near Virginia Game Commission Pier on the east side of
Atlantic Avenue near Riverview Avenue, 38.7 feet (11.8 m) SSW of the SW corner
of a 30 x 20-foot galvanized sheeted building, 25.0 feet (7.7 m) north of the NW
corner of the Virginia Game Commission pier, and 1.8 feet (0.6 m) SSE of power
pole # 29J/317A.  The bench mark is level with the ground, crimped on the top of
a stainless steel rod driven 36 feet (11 m), to refusal, and encased in a 6-inch
PVC pipe and concrete kick block.

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

                                                   PUBLICATION DATE:  07/06/1987
Station ID: 8631044                                SUPERCEDED DATE:   04/21/2003
Name:       WACHAPREAGUE, WACHAPREAGUE CHANNEL                
            VIRGINIA
NOAA Chart: 12210                                  Latitude:         37° 36.4' N
USGS Quad:  WACHAPREAGUE                           Longitude:        75° 41.2' W


                            T I D A L   D A T U M S 


Tidal datums at WACHAPREAGUE, WACHAPREAGUE CHANNEL based on:

     LENGTH OF SERIES:      6 YEARS
     TIME PERIOD:           1979-1984
     TIDAL EPOCH:           1960-1978
     CONTROL TIDE STATION:  8638610 HAMPTON ROADS


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

     HIGHEST OBSERVED WATER LEVEL (10/25/1980)         =   8.33
     MEAN HIGHER HIGH WATER                     MHHW   =   4.60
     MEAN HIGH WATER                            MHW    =   4.29
     MEAN TIDE LEVEL                            MTL    =   2.22
     MEAN LOW WATER                             MLW    =   0.15
     MEAN LOWER LOW WATER                       MLLW   =   0.00
     LOWEST  OBSERVED WATER LEVEL (03/16/1980)         =  -2.42



Bench Mark Elevation Information                In FEET above:

     Stamping or Designation                    MLLW        MHW

     1044 B 1978                                11.65      7.36
     1044 A 1978                                 6.12      1.83
     1044 C 1978                                 9.56      5.27
     1044 D 1978                                 8.26      3.97
     1044 E 1978                                 9.56      5.27
     1044 F 1981                                 7.23      2.94
     1044 G 1981                                 7.24      2.95


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

                                                   PUBLICATION DATE:  07/06/1987
Station ID: 8631044                                SUPERCEDED DATE:   04/21/2003
Name:       WACHAPREAGUE, WACHAPREAGUE CHANNEL                
            VIRGINIA
NOAA Chart: 12210                                  Latitude:         37° 36.4' N
USGS Quad:  WACHAPREAGUE                           Longitude:        75° 41.2' 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.

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