U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
Datums Page                                                        Page  1 of  7

                                                                                
Station ID: 8448725                         PUBLICATION DATE:  02/08/2013
Name:       MENEMSHA HARBOR                                   
            MA
NOAA Chart: 13233                           Latitude:   41° 21.3' N (  41.35444)
USGS Quad:  SQUIBNOCKET                     Longitude:  70° 46.1' W ( -70.76783)


To reach the station from the Vineyard Haven Ferry parking lot exit the parking
lot to the left onto Water St and proceed 0.2 km (0.1 mi) to the intersection of
Beach St. Water St., turn right onto Beach St and proceed 0.2 km (0.1 mi) to the
intersection of Beach St. and Main/State Rd, turn slightly to the left as Beach
St. becomes Main/State Rd. Proceed on State Rd. for 8.9 km (5.5mi). At the
intersection of North Rd. and State Rd. turn right and proceed 10.0 km (6.2 mi).
In the town of Menemsha at the intersection of North Rd. and Basin Rd. turn
right and proceed 0.4 km (0.3 mi) to the parking lot at the end of the road. The
station is located on the city of Chilmark?s finger pier that parallels the
harbors jetty.


                         T I D A L   B E N C H   M A R K S
                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  2 of  7

                                                                                
Station ID: 8448725                         PUBLICATION DATE:  02/08/2013
Name:       MENEMSHA HARBOR                                   
            MA
NOAA Chart: 13233                           Latitude:   41° 21.3' N (  41.35444)
USGS Quad:  SQUIBNOCKET                     Longitude:  70° 46.1' W ( -70.76783)


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


                 PRIMARY BENCH MARK STAMPING:  MEN 1 1994
                         DESIGNATION:          MEN 1

MONUMENTATION:           Tidal Station disk                    VM#:        18701
AGENCY:                  National Ocean Survey/Service (NOS)   IDB PID#:        
SETTING CLASSIFICATION:  Retaining wall                        OPUS PID#: BBDM82
LATITUDE:   41° 21.3' N (  41.35447)          LONGITUDE:  70° 46.0' W ( -70.76706)


The primary bench mark is set flush in the top of a retaining wall located
within vicinity of Menemsha Marina parking lot area, 51.10 m (167.7 ft) NW from
the NW corner of the gas station/general store, 9.80 m (32.2 ft) NE of the first
power pole along the pier, 2.70 m (8.9 ft) NW of the seventh electrical outlet
from the store along the retaining wall, and 0.2 m (0.7 ft) sea of the NE face
of the retaining.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  3 of  7

                                                                                
Station ID: 8448725                         PUBLICATION DATE:  02/08/2013
Name:       MENEMSHA HARBOR                                   
            MA
NOAA Chart: 13233                           Latitude:   41° 21.3' N (  41.35444)
USGS Quad:  SQUIBNOCKET                     Longitude:  70° 46.1' W ( -70.76783)


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


                         BENCH MARK STAMPING:  MEN 2 1994
                         DESIGNATION:          MEN 2

MONUMENTATION:           Tidal Station disk                    VM#:        18702
AGENCY:                  National Ocean Survey/Service (NOS)   IDB PID#:        
SETTING CLASSIFICATION:  Retaining wall                        OPUS PID:        
LATITUDE:   41° 21.3' N (  41.35436)          LONGITUDE:  70° 46.0' W ( -70.76650)


The bench mark is set flush in the top of a retaining wall located in the
vicinity of the Menemesha Marina parking lot, 13.90 m (45.6 ft) north of the
northern most bollard along the retaining wall, 4.30 m (14.1 ft) SE of the first
electrical outlet from the general store along the retaining wall, 3.70 m (12.1
ft) west of the NW corner of the gas station/general store and 3.30 m (10.8 ft)
east of the water's edge.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  4 of  7

                                                                                
Station ID: 8448725                         PUBLICATION DATE:  02/08/2013
Name:       MENEMSHA HARBOR                                   
            MA
NOAA Chart: 13233                           Latitude:   41° 21.3' N (  41.35444)
USGS Quad:  SQUIBNOCKET                     Longitude:  70° 46.1' W ( -70.76783)


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


                         BENCH MARK STAMPING:  MEN 3 1994
                         DESIGNATION:          MEN 3

MONUMENTATION:           Tidal Station disk                    VM#:        18703
AGENCY:                  National Ocean Survey/Service (NOS)   IDB PID#:        
SETTING CLASSIFICATION:  Retaining wall                        OPUS PID:        
LATITUDE:   41° 21.2' N (  41.35417)          LONGITUDE:  70° 46.0' W ( -70.76625)


The bench mark is set flush in the top of the retaining wall located in the
vicinity of the Menemsha Marina parking lot,  22.40 m (73.5 ft) west of utility
pole by the fish market, 18.90 m (62.0 ft) SE of the centerline Basin Road,
19.00 m (52.5 ft) SSW of a utility pole in front of the dockmaster's office,
3.40 m (11.2 ft) east of the water's edge.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  5 of  7

                                                                                
Station ID: 8448725                         PUBLICATION DATE:  02/08/2013
Name:       MENEMSHA HARBOR                                   
            MA
NOAA Chart: 13233                           Latitude:   41° 21.3' N (  41.35444)
USGS Quad:  SQUIBNOCKET                     Longitude:  70° 46.1' W ( -70.76783)


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


                         BENCH MARK STAMPING:  MEN 5 1994
                         DESIGNATION:          MEN 5

MONUMENTATION:           Tidal Station disk                    VM#:        18705
AGENCY:                  National Ocean Survey/Service (NOS)   IDB PID#:        
SETTING CLASSIFICATION:  Bridge abutment                       OPUS PID:        
LATITUDE:   41° 21.2' N (  41.35350)          LONGITUDE:  70° 45.9' W ( -70.76528)


The bench mark is set flush in the NE corner of the bridges abutment located in
the vicinity of the Menemsha Marina parking lot, 38.70 m (127.0 ft) north of a
power pole on the corner of Basin Road and the dead end street, 16.50 m (54.1
ft) east of the east corner of the first building on the west side of the
marina, 4.60 m (15.09 ft) NE of the centerline of Basin Road.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  6 of  7

                                                                                
Station ID: 8448725                         PUBLICATION DATE:  02/08/2013
Name:       MENEMSHA HARBOR                                   
            MA
NOAA Chart: 13233                           Latitude:   41° 21.3' N (  41.35444)
USGS Quad:  SQUIBNOCKET                     Longitude:  70° 46.1' W ( -70.76783)


                            T I D A L   D A T U M S 


Tidal datums at MENEMSHA HARBOR based on:

     LENGTH OF SERIES:      3 YEARS
     TIME PERIOD:           Sept 2008 thru Aug 2010 & May 2011 thru April 2012
     TIDAL EPOCH:           1983-2001
     CONTROL TIDE STATION:  8452660 NEWPORT, NARRAGANSETT BAY


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

     HIGHEST OBSERVED WATER LEVEL (12/12/2008)         =  1.651
     MEAN HIGHER HIGH WATER                     MHHW   =  0.956
     MEAN HIGH WATER                            MHW    =  0.878
     MEAN TIDE LEVEL                            MTL    =  0.458
     MEAN SEA LEVEL                             MSL    =  0.417
     MEAN LOW WATER                             MLW    =  0.038
     MEAN LOWER LOW WATER                       MLLW   =  0.000
     LOWEST  OBSERVED WATER LEVEL (01/30/2010)         = -0.500

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MLLW        MHW

     MEN 1 1994                                  2.306    1.428
     MEN 2 1994                                  2.307    1.429
     MEN 3 1994                                  2.304    1.426
     MEN 5 1994                                  2.361    1.483


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

                                                                                
Station ID: 8448725                         PUBLICATION DATE:  02/08/2013
Name:       MENEMSHA HARBOR                                   
            MA
NOAA Chart: 13233                           Latitude:   41° 21.3' N (  41.35444)
USGS Quad:  SQUIBNOCKET                     Longitude:  70° 46.1' W ( -70.76783)


                             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.