U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
Datums Page                                                        Page  1 of  8

                                                                                
Station ID: 8447270                         PUBLICATION DATE:  04/21/2003
Name:       BUZZARDS BAY (RR BRIDGE), CAPE COD CANAL          
            MA
NOAA Chart: 13236                           Latitude:   41° 44.5' N (  41.74170)
USGS Quad:  POCASSET                        Longitude:  70° 37.0' W ( -70.61670)


To reach the tidal bench marks from the Post Office at Buzzards Bay, proceed
west on Main Street 0.8 km (0.5 mi) to Academy Road, turn left on Academy Road
and continue south for 0.3 km (0,2 mi) to the U.S. Army Corps of Engineers
reservation and the concrete pier at the boat basin.  The bench marks are at the
reservation and at the railroad depot in Buzzards Bay.  The tide gage was on the
north side of the concrete pier at the basin.


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


                 PRIMARY BENCH MARK STAMPING:  NO 2 1931
                         DESIGNATION:          844 7270 TIDAL 2

MONUMENTATION:           Tidal Station disk                    VM#:         2007
AGENCY:                  US Coast and Geodetic Survey
                         (USC&GS)                              IDB PID#:  LW1552
SETTING CLASSIFICATION:  Building foundation                   OPUS PID:        
LATITUDE:   41° 44.6' N (  41.74330)          LONGITUDE:  70° 36.9' W ( -70.61500)


The primary bench mark is a disk set in the concrete foundation of the Railroad
Station (Chamber of Commerce) on Main Street in Buzzards Bay, 2 m (5 ft) north
of the center of the east entrance, 1.37 m (4.5 ft) west of the east side of the
building, and level with the floor of the station.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  2 of  8

                                                                                
Station ID: 8447270                         PUBLICATION DATE:  04/21/2003
Name:       BUZZARDS BAY (RR BRIDGE), CAPE COD CANAL          
            MA
NOAA Chart: 13236                           Latitude:   41° 44.5' N (  41.74170)
USGS Quad:  POCASSET                        Longitude:  70° 37.0' W ( -70.61670)


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


                         BENCH MARK STAMPING:  NO 4 1965
                         DESIGNATION:          844 7270 TIDAL 4

MONUMENTATION:           Tidal Station disk                    VM#:         2008
AGENCY:                  US Coast and Geodetic Survey
                         (USC&GS)                              IDB PID#:        
SETTING CLASSIFICATION:  Concrete bulkhead                     OPUS PID#: BBBJ55
LATITUDE:   41° 44.5' N (  41.74170)          LONGITUDE:  70° 37.0' W ( -70.61670)


The bench mark is a disk set in the east end of a 1 m x 4 m (2 ft x 12 ft)
concrete bulkhead for an abandoned pier on the Cape Cod Canal, 36 m (118 ft) SSW
of the SW corner of the maintenance building, 16.50 m (54.1 ft) SE of a gasoline
pump near the foot of a concrete pier, and 13.60 m (44.6 ft) east of the SE
corner of the pier.



                         BENCH MARK STAMPING:  NO 5 1975
                         DESIGNATION:          844 7270 TIDAL 5

MONUMENTATION:           Tidal Station disk                    VM#:         2009
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Concrete apron                        OPUS PID:        
LATITUDE:   41° 44.5' N (  41.74170)          LONGITUDE:  70° 37.0' W ( -70.61670)


The bench mark is a disk set in the NE corner of a concrete apron leading to a
loading ramp on the north side of the stockroom building on the reservation, 46
m (150 ft) SE of the corner of a large equipment shed, 15.21 m (49.9 ft) south
of the south edge of a road running east-west through the reservation and across
the railroad tracks, 5.91 m (19.4 ft) west of a railroad spur along the east
side of the stockroom building, and 4.60 m (15.1 ft) north of the north face of
the stockroom building.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  3 of  8

                                                                                
Station ID: 8447270                         PUBLICATION DATE:  04/21/2003
Name:       BUZZARDS BAY (RR BRIDGE), CAPE COD CANAL          
            MA
NOAA Chart: 13236                           Latitude:   41° 44.5' N (  41.74170)
USGS Quad:  POCASSET                        Longitude:  70° 37.0' W ( -70.61670)


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


                         BENCH MARK STAMPING:  NO 6 1975
                         DESIGNATION:          844 7270 TIDAL 6

MONUMENTATION:           Tidal Station disk                    VM#:         2010
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Concrete pad                          OPUS PID#: BBCF80
LATITUDE:   41° 44.5' N (  41.74170)          LONGITUDE:  70° 37.0' W ( -70.61670)


The bench mark is a disk set flush in a 0.85 m x 0.73 m (2.8 ft x 2.4 ft)
concrete pad outside the fence surrounding the reservation, 76 m (250 ft) WNW of
the railroad bridge over Cape Cod Canal, 16.15 m (53.0 ft) south of a road
running east-west through the reservation and across the railroad tracks, 12 m
(40 ft) east of the NE corner of the east warehouse, 9.45 m (31.0 ft) west of
the tracks, and 1.22 m (4.0 ft) east of a base perimeter fence.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  4 of  8

                                                                                
Station ID: 8447270                         PUBLICATION DATE:  04/21/2003
Name:       BUZZARDS BAY (RR BRIDGE), CAPE COD CANAL          
            MA
NOAA Chart: 13236                           Latitude:   41° 44.5' N (  41.74170)
USGS Quad:  POCASSET                        Longitude:  70° 37.0' W ( -70.61670)


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


                         BENCH MARK STAMPING:   
                         DESIGNATION:          844 7270 A48
                         ALIAS:                A48

MONUMENTATION:           See descriptive text                  VM#:         2012
AGENCY:                  Unknown                               IDB PID#:        
SETTING CLASSIFICATION:  Tower foundation                      OPUS PID:        
LATITUDE:   41° 44.5' N (  41.74170)          LONGITUDE:  70° 37.0' W ( -70.61670)


The bench mark is a copper plug located on the west corner of the railroad
switch tower U-416 near the railroad station in Buzzards Bay. Note: the plug is
painted white and is somewhat difficult to see.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  5 of  8

                                                                                
Station ID: 8447270                         PUBLICATION DATE:  04/21/2003
Name:       BUZZARDS BAY (RR BRIDGE), CAPE COD CANAL          
            MA
NOAA Chart: 13236                           Latitude:   41° 44.5' N (  41.74170)
USGS Quad:  POCASSET                        Longitude:  70° 37.0' W ( -70.61670)


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


                         BENCH MARK STAMPING:   
                         DESIGNATION:          844 7270 J17
                         ALIAS:                J 17

MONUMENTATION:           Chiseled Square                       VM#:         2013
AGENCY:                  Unknown                               IDB PID#:        
SETTING CLASSIFICATION:  Granite step                          OPUS PID:        
LATITUDE:   41° 44.5' N (  41.74170)          LONGITUDE:  70° 37.0' W ( -70.61670)


The bench mark is a chiseled square in the corner sill that abuts the NW end of
a granite step at the NE entrance of the railroad station (Chamber of Commerce)
at Buzzards Bay, and 4.42 m (14.5 ft) SE of the north corner of the station.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  6 of  8

                                                                                
Station ID: 8447270                         PUBLICATION DATE:  04/21/2003
Name:       BUZZARDS BAY (RR BRIDGE), CAPE COD CANAL          
            MA
NOAA Chart: 13236                           Latitude:   41° 44.5' N (  41.74170)
USGS Quad:  POCASSET                        Longitude:  70° 37.0' W ( -70.61670)


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


                         BENCH MARK STAMPING:   
                         DESIGNATION:          844 7270 NWRR (USE)
                         ALIAS:                NWRR (USE)

MONUMENTATION:           See descriptive text                  VM#:         2014
AGENCY:                  Unknown                               IDB PID#:        
SETTING CLASSIFICATION:  Concrete abutment                     OPUS PID:        
LATITUDE:   41° 44.5' N (  41.74170)          LONGITUDE:  70° 37.0' W ( -70.61670)


The bench mark is a brass plug set in the north concrete abutment of the
railroad bridge over Cape Cod Canal, just outside the fence at the Corps of
Engineers reservation, 6 m (20 ft) SW of the centerline of the railroad tracks,
3 m (10 ft) NW of the NW corner of the bridge abutment, and 2 m (6 ft) below
track level.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  7 of  8

                                                                                
Station ID: 8447270                         PUBLICATION DATE:  04/21/2003
Name:       BUZZARDS BAY (RR BRIDGE), CAPE COD CANAL          
            MA
NOAA Chart: 13236                           Latitude:   41° 44.5' N (  41.74170)
USGS Quad:  POCASSET                        Longitude:  70° 37.0' W ( -70.61670)


                            T I D A L   D A T U M S 


Tidal datums at BUZZARDS BAY (RR BRIDGE), CAPE COD CANAL based on:

     LENGTH OF SERIES:      2 Months
     TIME PERIOD:           August 2000 - September 2000
     TIDAL EPOCH:           1983-2001
     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   =  1.217
     MEAN HIGH WATER                            MHW    =  1.111
     MEAN TIDE LEVEL                            MTL    =  0.589
     MEAN SEA LEVEL                             MSL    =  0.548
     MEAN LOW WATER                             MLW    =  0.067
     MEAN LOWER LOW WATER                       MLLW   =  0.000

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MLLW        MHW

     NO 2 1931                                   3.433    2.322
     NO 4 1965                                   2.554    1.443
     NO 5 1975                                   3.246    2.135
     NO 6 1975                                   3.481    2.370
     844 7270 A48                                3.301    2.190
     844 7270 J17                                3.434    2.323
     844 7270 NWRR (USE)                         2.376    1.265


                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  8 of  8

                                                                                
Station ID: 8447270                         PUBLICATION DATE:  04/21/2003
Name:       BUZZARDS BAY (RR BRIDGE), CAPE COD CANAL          
            MA
NOAA Chart: 13236                           Latitude:   41° 44.5' N (  41.74170)
USGS Quad:  POCASSET                        Longitude:  70° 37.0' W ( -70.61670)


                             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.