Superseded Bench Mark Sheet for 8447295, Gray Gables MA

Present Epoch

Printable version

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
Datums Page                                                        Page  1 of  5

                                                   PUBLICATION DATE:  06/27/2001
Station ID: 8447295                                SUPERCEDED DATE:   04/21/2003
Name:       GRAY GABLES, BUZZARDS BAY, MA                     
            MASSACHUSETTS
NOAA Chart: 13230                                  Latitude:         41° 44.1' N
USGS Quad:  POCASSET                               Longitude:        70° 37.4' W


To reach the tidal bench marks from the first traffic rotary after crossing
south over the Bourne Bridge (Route 28 south),  proceed NW at the first exit -
Trowbridge Road, following the signs for Mashnee Village for 1.0 km (0.6 mi) to
Shore Road, then continue straight on Shore Road for 1.4 km (0.9 mi) to Monument
Neck Road, stay right and proceed straight (WSW) on Monument Neck Road for 0.2
km (0.1 mi) to Presidents Road, turn right and continue on Presidents Road for
0.3 km (0.2 mi), turn left and continue on Presidents Road for 0.3 km (0.2 mi),
then turn right and go 0.3 km (0.2 mi) to No. 211 Presidents Road. The bench
marks are located along Presidents, Bryant, and Beverly Roads. The tide gauge
was located on the NW end of the private pier behind No. 211 Presidents Road.


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


                 PRIMARY BENCH MARK STAMPING:  7295 C 2000
                         DESIGNATION:          844 7295 C

MONUMENTATION:           Tidal Station disk                        VM#:    16262
AGENCY:                  National Ocean Service (NOS)              PID:         
SETTING CLASSIFICATION:  Sea wall


The primary bench mark is a disk set in the NW corner of the junction of two sea
walls along the beach at No. 7 Bryant Road, in a patch of wild roses, 23.65 m
(77.6 ft) NNW of the NW corner of the house, 17.50 m (57.4 ft) NNE of the center
of a walkway leading from the back of the house to the beach, 3 m (10 ft) SSW of
a low stone wall, and 0.20 m (0.7 ft) above ground level.



                         BENCH MARK STAMPING:  7295 A 2000
                         DESIGNATION:          844 7295 A

MONUMENTATION:           Tidal Station disk                        VM#:    16263
AGENCY:                  National Ocean Service (NOS)              PID:         
SETTING CLASSIFICATION:  Concrete base


The bench mark is a disk set in the west corner of the concrete base of an
ornamental lighthouse at No. 216 Presidents Road, the last house on Presidents
Road, 28.42 m (93.2 ft) north of the western of two stone entrance pillars at
the end of the road, 27.80 m (91.2 ft) WNW of the NE corner of the house, 15.75
m (51.7 ft) NE of the NE edge of an old paved road on the point, and 0.10 m (0.3
ft) above ground level.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  2 of  5

                                                   PUBLICATION DATE:  06/27/2001
Station ID: 8447295                                SUPERCEDED DATE:   04/21/2003
Name:       GRAY GABLES, BUZZARDS BAY, MA                     
            MASSACHUSETTS
NOAA Chart: 13230                                  Latitude:         41° 44.1' N
USGS Quad:  POCASSET                               Longitude:        70° 37.4' W


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


                         BENCH MARK STAMPING:  7295 B 2000
                         DESIGNATION:          844 7295 B

MONUMENTATION:           Tidal Station disk                        VM#:    16264
AGENCY:                  National Ocean Service (NOS)              PID:         
SETTING CLASSIFICATION:  Retaining wall


The bench mark is a disk set in the NW end of a concrete retaining wall on the
NW side of the driveway at No. 8 Bryant Road, 21.75 m (71.4 ft) SSW of power
pole No. 1, 19.15 m (62.8 ft) NE of power pole No. 2, 6.40 m (21.0 ft) ESE of
the center of Bryant Road, and 0.40 m (1.3 ft) above ground level.



                         BENCH MARK STAMPING:  7295 D 2000
                         DESIGNATION:          844 7295 D

MONUMENTATION:           Tidal Station disk                        VM#:    16265
AGENCY:                  National Ocean Service (NOS)              PID:         
SETTING CLASSIFICATION:  Retaining wall


The bench mark is a disk set in the NW end of the SW retaining wall of the
driveway at No. 36 Benedict Road, 11.93 m (39.1 ft) west of the NW corner of the
house, 9.80 m (32.2 ft) north of the SE corner of No. 40 Benedict Road, 9.25 m
(30.3 ft) SSE of the center of Benedict Road, and 0.35 m (1.1 ft) above the
driveway.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  3 of  5

                                                   PUBLICATION DATE:  06/27/2001
Station ID: 8447295                                SUPERCEDED DATE:   04/21/2003
Name:       GRAY GABLES, BUZZARDS BAY, MA                     
            MASSACHUSETTS
NOAA Chart: 13230                                  Latitude:         41° 44.1' N
USGS Quad:  POCASSET                               Longitude:        70° 37.4' W


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


                         BENCH MARK STAMPING:  7295 E 2000
                         DESIGNATION:          844 7295 E

MONUMENTATION:           Tidal Station disk                        VM#:    16266
AGENCY:                  National Ocean Service (NOS)              PID:         
SETTING CLASSIFICATION:  Concrete pier


The bench mark is a disk set in the concrete dock at No. 39 Benedict Road, near
the foot of the steps leading down from the house to the pier, 8.55 m (28.1 ft)
WNW of the NE corner of the house, 7.30 m (24.0 ft) north of the NW corner of
the house, and 0.70 m (2.3 ft) NNW of the sea wall.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  4 of  5

                                                   PUBLICATION DATE:  06/27/2001
Station ID: 8447295                                SUPERCEDED DATE:   04/21/2003
Name:       GRAY GABLES, BUZZARDS BAY, MA                     
            MASSACHUSETTS
NOAA Chart: 13230                                  Latitude:         41° 44.1' N
USGS Quad:  POCASSET                               Longitude:        70° 37.4' W


                            T I D A L   D A T U M S 


Tidal datums at GRAY GABLES, BUZZARDS BAY, MA based on:

     LENGTH OF SERIES:      2 MONTHS
     TIME PERIOD:           August 2000 - September 2000
     TIDAL EPOCH:           1960-1978
     CONTROL TIDE STATION:  8452660 NEWPORT, NARRAGANSETT BAY


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

     MEAN HIGHER HIGH WATER                     MHHW   =  1.272
     MEAN HIGH WATER                            MHW    =  1.173
     MEAN TIDE LEVEL                            MTL    =  0.613
     MEAN SEA LEVEL                             MSL    =  0.549
     MEAN LOW WATER                             MLW    =  0.052
     MEAN LOWER LOW WATER                       MLLW   =  0.000



Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MLLW        MHW

     7295 C 2000                                 2.187    1.014
     7295 A 2000                                 2.443    1.270
     7295 B 2000                                 3.147    1.974
     7295 D 2000                                 4.743    3.570
     7295 E 2000                                 1.942    0.769


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

                                                   PUBLICATION DATE:  06/27/2001
Station ID: 8447295                                SUPERCEDED DATE:   04/21/2003
Name:       GRAY GABLES, BUZZARDS BAY, MA                     
            MASSACHUSETTS
NOAA Chart: 13230                                  Latitude:         41° 44.1' N
USGS Quad:  POCASSET                               Longitude:        70° 37.4' 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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