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

                                                                                
Station ID: 8445138                         PUBLICATION DATE:  02/05/2004
Name:       SCITUATE, SCITUATE HARBOR                         
            MA
NOAA Chart: 13269                           Latitude:   42° 12.1' N (  42.20170)
USGS Quad:  SCITUATE                        Longitude:  70° 43.6' W ( -70.72670)


To reach the tidal bench marks from the intersection of State Routes 3 and 14
(Exit 11 on State Route 3), proceed east on State Route 14 for 1.0 km (0.6 mi)
to State Route 139, then continue west on State Route 139 for 1.8 km (1.1 mi) to
State Route 3A, then turn left and proceed north on State Route 3A for 15.4 km
(9.6 mi) to First Parish Road, then turn right and proceed east on First Parish
Road for 4.0 km (2.5 mi) to Front Street, then turn left and proceed NE on Front
Street for 0.6 km (0.4 mi) to Jericho Road, continue north on Jericho Road for
0.5 km (0.3 mi) to Scituate Harbor Marina.  The bench marks are near the marina
and along Front Street and Jericho Road.  The tide gage and staff were on the
east end of the marina pier.


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


                 PRIMARY BENCH MARK STAMPING:  5138 A 1990
                         DESIGNATION:          844 5138 A

MONUMENTATION:           Tidal Station disk                    VM#:         1467
AGENCY:                  National Ocean Service (NOS)          IDB PID#:        
SETTING CLASSIFICATION:  Concrete sea wall                     OPUS PID#: BBBJ43
LATITUDE:   42° 12.1' N (  42.20170)          LONGITUDE:  70° 43.6' W ( -70.72670)


The primary bench mark is a disk set in the bend of the concrete sea wall
located in the NE corner of the Scituate Harbor Marina parking lot, 37.31 m
(122.4 ft) SW of the NE corner of the west end of the sea wall, 21.52 m (70.6
ft) north of utility pole #11B, 0.30 m (1.0 ft) NW of the SE corner of the sea
wall, and 0.37 m (1.2 ft) above the parking lot.

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

                                                                                
Station ID: 8445138                         PUBLICATION DATE:  02/05/2004
Name:       SCITUATE, SCITUATE HARBOR                         
            MA
NOAA Chart: 13269                           Latitude:   42° 12.1' N (  42.20170)
USGS Quad:  SCITUATE                        Longitude:  70° 43.6' W ( -70.72670)


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


                         BENCH MARK STAMPING:  GATE 1924
                         DESIGNATION:          GATE
                         ALIAS:                4 USE

MONUMENTATION:           Bench Mark disk                       VM#:         1468
AGENCY:                  US Army Corps of Engineers (USE)      IDB PID#:        
SETTING CLASSIFICATION:  Rock wall                             OPUS PID:        
LATITUDE:   42° 12.1' N (  42.20170)          LONGITUDE:  70° 43.6' W ( -70.72670)


The bench mark is a disk set in a rock wall east of 8 Beaver Dam Road, 25 m (83
ft) north of the NW corner of 4 Beaver Dam Road, 23 m (74 ft) east of the SE
porch corner of 8 Beaver Dam Road, and 1.86 m (6.1 ft) west of a wooden light
pole at the inshore end of a pier.



                         BENCH MARK STAMPING:  NO 7 1952
                         DESIGNATION:          844 5138 TIDAL 7

MONUMENTATION:           Tidal Station disk                    VM#:         1469
AGENCY:                  US Coast and Geodetic Survey
                         (USC&GS)                              IDB PID#:        
SETTING CLASSIFICATION:  Concrete sea wall                     OPUS PID:        
LATITUDE:   42° 12.1' N (  42.20170)          LONGITUDE:  70° 43.6' W ( -70.72670)


The bench mark is a disk set in the sea wall located on the east side of Front
Street and south of the entrance to the marina pier, 8.26 m (27.1 ft) SSE of a
power pole, 6.25 m (20.5 ft) east of the centerline of Front Street, 0.15 m (0.5
ft) west of the edge of the sea wall, and 0.64 m (2.1 ft) below the level of the
sidewalk.

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

                                                                                
Station ID: 8445138                         PUBLICATION DATE:  02/05/2004
Name:       SCITUATE, SCITUATE HARBOR                         
            MA
NOAA Chart: 13269                           Latitude:   42° 12.1' N (  42.20170)
USGS Quad:  SCITUATE                        Longitude:  70° 43.6' W ( -70.72670)


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


                         BENCH MARK STAMPING:  5138 B 1990
                         DESIGNATION:          844 5138 B

MONUMENTATION:           Tidal Station disk                    VM#:         1470
AGENCY:                  National Ocean Service (NOS)          IDB PID#:        
SETTING CLASSIFICATION:  Concrete foundation                   OPUS PID:        
LATITUDE:   42° 12.1' N (  42.20170)          LONGITUDE:  70° 43.6' W ( -70.72670)


The bench mark is a disk set in a concrete foundation located at the west end of
the Scituate Harbor Boat Club pier, 20.12 m (66.0 ft) SW of the flagpole at the
boat club, 10.30 m (33.8 ft) south of the SE corner of the boat club building,
0.91 m (3.0 ft) NE of the SW corner of the foundation, and 0.30 m (1.0 ft) above
ground level.

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

                                                                                
Station ID: 8445138                         PUBLICATION DATE:  02/05/2004
Name:       SCITUATE, SCITUATE HARBOR                         
            MA
NOAA Chart: 13269                           Latitude:   42° 12.1' N (  42.20170)
USGS Quad:  SCITUATE                        Longitude:  70° 43.6' W ( -70.72670)


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


                         BENCH MARK STAMPING:   
                         DESIGNATION:          844 5138 BM 4
                         ALIAS:                NO STAMPING 1 (4 1924)

MONUMENTATION:           Bench Mark disk                       VM#:         1471
AGENCY:                  US Coast and Geodetic Survey
                         (USC&GS)                              IDB PID#:        
SETTING CLASSIFICATION:  Rock wall                             OPUS PID:        
LATITUDE:   42° 12.1' N (  42.20170)          LONGITUDE:  70° 43.6' W ( -70.72670)


The bench mark is a disk set in a rock wall located NNE of 8 Beaver Dam Road, 31
m (101 ft) NW of bench mark GATE 1924, 20.57 m (67.5 ft) south of a chain link
fence, and 15.64 m (51.3 ft) NNE of the NE porch corner of 8 Beaver Dam Road.

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

                                                                                
Station ID: 8445138                         PUBLICATION DATE:  02/05/2004
Name:       SCITUATE, SCITUATE HARBOR                         
            MA
NOAA Chart: 13269                           Latitude:   42° 12.1' N (  42.20170)
USGS Quad:  SCITUATE                        Longitude:  70° 43.6' W ( -70.72670)


                            T I D A L   D A T U M S 


Tidal datums at SCITUATE, SCITUATE HARBOR based on:

     LENGTH OF SERIES:      3 MONTHS
     TIME PERIOD:           June 1990 - August 1990
     TIDAL EPOCH:           1983-2001
     CONTROL TIDE STATION:  8443970 BOSTON, BOSTON HARBOR


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

     MEAN HIGHER HIGH WATER                     MHHW   =  2.970
     MEAN HIGH WATER                            MHW    =  2.834
     MEAN SEA LEVEL                             MSL    =  1.491
     MEAN TIDE LEVEL                            MTL    =  1.471
     MEAN LOW WATER                             MLW    =  0.108
     MEAN LOWER LOW WATER                       MLLW   =  0.000

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MLLW        MHW

     5138 A 1990                                 4.708    1.874
     GATE 1924                                   4.915    2.081
     NO 7 1952                                   4.468    1.634
     5138 B 1990                                 4.954    2.120
     844 5138 BM 4                               4.992    2.158


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

                                                                                
Station ID: 8445138                         PUBLICATION DATE:  02/05/2004
Name:       SCITUATE, SCITUATE HARBOR                         
            MA
NOAA Chart: 13269                           Latitude:   42° 12.1' N (  42.20170)
USGS Quad:  SCITUATE                        Longitude:  70° 43.6' W ( -70.72670)


                             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.