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

                                                                                
Station ID: 8460751                         PUBLICATION DATE:  06/20/2016
Name:       WEST MYSTIC, MYSTIC RIVER                         
            CT
NOAA Chart: 13214                           Latitude:   41° 20.6' N (  41.34330)
USGS Quad:  Mystic                          Longitude:  71° 58.5' W ( -71.97500)


To reach the station from the US Highway 1 (Main Street) bridge over the Mystic
River in Mystic, proceed west on US Highway 1 for 0.2 km (0.1 mi) to Water
Street (State Highway 215), turn left and proceed south for 1.1 km (0.7 mi) on
State Highway 215 to School Street on the left, turn left and proceed southeast
for 0.3 km (0.2 mi) to its termination at Essex Street. Turn right and proceed
southwest for 0.1 km (0.1 mi) to the Mystic Shipyard on the left at 100 Essex
Street. The bench marks are located between the north end of Casino Road and the
intersection of State Highway 215 and Cedar Road. The tide gauge is located on
the west end of the north pier at Mystic Shipyard.


                         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  8

                                                                                
Station ID: 8460751                         PUBLICATION DATE:  06/20/2016
Name:       WEST MYSTIC, MYSTIC RIVER                         
            CT
NOAA Chart: 13214                           Latitude:   41° 20.6' N (  41.34330)
USGS Quad:  Mystic                          Longitude:  71° 58.5' W ( -71.97500)


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


                 PRIMARY BENCH MARK STAMPING:  NO 1 1917
                         DESIGNATION:          TIDAL 1 STA 2

MONUMENTATION:           DJ                                    VM#:        21427
AGENCY:                  US Coast & Geodetic Survey            IDB PID#:  LW0715
SETTING CLASSIFICATION:  In rock outcrop                       OPUS PID:        
LATITUDE:   41° 20.8' N (  41.34611)          LONGITUDE:  71° 58.5' W ( -71.97469)


The primary bench mark is a disk set in a bedrock outcrop on the E end of the
property at the shoreline, 23.93 m (78.5 ft) E of a  6.1 m (20 ft) tall post,
19.95 m (65.5 ft) ENE of the center of a flue for an outdoor stone fireplace,
12.35 m (40.5 ft) SSE of the NE corner of an abandoned house, 10.92 m (35.8 ft)
E of a 25 cm (10 in) diameter oak tree and 8.07 m (26.5 ft) SE of the SE corner
of an abandoned house.



                         BENCH MARK STAMPING:  0751 A 2015
                         DESIGNATION:          846 0751 A

MONUMENTATION:           DB                                    VM#:        21428
AGENCY:                  National Ocean Service                IDB PID#:        
SETTING CLASSIFICATION:  Footings/foundation walls of
                         small/medium structures               OPUS PID:        
LATITUDE:   41° 20.6' N (  41.34372)          LONGITUDE:  71° 58.4' W ( -71.97400)


The bench mark is a disk set in an E facing garage door in the concrete footing
of a shop building on the NE side of the shipyard, 21.21 m (69.6 ft) W of a
piling N of a gated access pier labeled with the letter C, 17.90 m (58.7 ft) NW
of the N piling at the corner of a steel seawall of the dock, 16.85 m (55.3 ft)
W of a telephone pedestal near the intersection of the armor rock seawall and
steel seawall, 8.96 m (29.4 ft) NNE of the center of the N most man door to the
building and 2.47 m (8.1 ft) SSW of the NE corner of the building.

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

                                                                                
Station ID: 8460751                         PUBLICATION DATE:  06/20/2016
Name:       WEST MYSTIC, MYSTIC RIVER                         
            CT
NOAA Chart: 13214                           Latitude:   41° 20.6' N (  41.34330)
USGS Quad:  Mystic                          Longitude:  71° 58.5' W ( -71.97500)


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


                         BENCH MARK STAMPING:  HILL 1934
                         DESIGNATION:          HILL

MONUMENTATION:           DS                                    VM#:        21429
AGENCY:                  US Coast & Geodetic Survey            IDB PID#:  LW0714
SETTING CLASSIFICATION:  In rock outcrop                       OPUS PID:        
LATITUDE:   41° 20.4' N (  41.34053)          LONGITUDE:  71° 58.7' W ( -71.97900)


The bench mark is a disk set in bedrock at a location named the point N of
sixpenny island as named by USGS, 41.8 m (137.1 ft) ESE of the E rail of the
railroad tracks, and 7.10 m (23.3 ft) NW of of a 1.0 ft (0.3 m) long bent metal
rod embedded in bedrock.

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

                                                                                
Station ID: 8460751                         PUBLICATION DATE:  06/20/2016
Name:       WEST MYSTIC, MYSTIC RIVER                         
            CT
NOAA Chart: 13214                           Latitude:   41° 20.6' N (  41.34330)
USGS Quad:  Mystic                          Longitude:  71° 58.5' W ( -71.97500)


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


                         BENCH MARK STAMPING:  HILL NO 1 1934
                         DESIGNATION:          HILL RM 1

MONUMENTATION:           DR                                    VM#:        21430
AGENCY:                  US Coast & Geodetic Survey            IDB PID#:  LW0712
SETTING CLASSIFICATION:  In rock outcrop                       OPUS PID:        
LATITUDE:   41° 20.4' N (  41.34053)          LONGITUDE:  71° 58.7' W ( -71.97869)


The bench mark is a disk set in bedrock at a location named the point N of
sixpenny island as named by USGS, 26.55 m (87.1 ft) E of station hill set at the
highest point on the bedrock at the point, 24.95 m (81.9 ft) ESE of the SE
corner of an old stone foundation, and 3.84 m (12.6 ft) W of a cliff leading
down to the water line.

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

                                                                                
Station ID: 8460751                         PUBLICATION DATE:  06/20/2016
Name:       WEST MYSTIC, MYSTIC RIVER                         
            CT
NOAA Chart: 13214                           Latitude:   41° 20.6' N (  41.34330)
USGS Quad:  Mystic                          Longitude:  71° 58.5' W ( -71.97500)


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


                         BENCH MARK STAMPING:  HILL NO 2 1934
                         DESIGNATION:          HILL RM 2

MONUMENTATION:           DR                                    VM#:        21431
AGENCY:                  US Coast & Geodetic Survey            IDB PID#:  LW0713
SETTING CLASSIFICATION:  In rock outcrop                       OPUS PID:        
LATITUDE:   41° 20.4' N (  41.34042)          LONGITUDE:  71° 58.7' W ( -71.97881)


The bench mark is a disk set in bedrock at a location named the point N of
sixpenny island as named by USGS, 16.00 m (52.5 ft) ESE of station hill on the
highest bedrock at the point, 12.65 m (41.5 ft) N of a concrete wall at the
shoreline where bedrock meets the mudflats and 9.75 m (32.0 ft) ESE of a 0.3 m
(1.0 ft) bent metal rod embedded in the bedrock.

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

                                                                                
Station ID: 8460751                         PUBLICATION DATE:  06/20/2016
Name:       WEST MYSTIC, MYSTIC RIVER                         
            CT
NOAA Chart: 13214                           Latitude:   41° 20.6' N (  41.34330)
USGS Quad:  Mystic                          Longitude:  71° 58.5' W ( -71.97500)


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


                         BENCH MARK STAMPING:  V 37 1965
                         DESIGNATION:          V 37

MONUMENTATION:           DB                                    VM#:        21432
AGENCY:                  Coast and Geodetic Survey             IDB PID#:  LW0711
SETTING CLASSIFICATION:  In rock outcrop                       OPUS PID#: LW0711
LATITUDE:   41° 20.5' N (  41.34203)          LONGITUDE:  71° 59.0' W ( -71.98272)


The bench mark is a disk set in bedrock, 25.30 m (83.0 ft) NNW of center of a
catch basin W of residence driveway on Noank road, 24.35 m (79.9 ft) S of a
utility pole in the residence front yard, 23.76 m (78.0 ft) NNW of a fire
hydrant, 9.45 m (31.0 ft) W of the centerline of the residence driveway
perpendicular to the rock formation and 3.99 m (13.1 ft) ENE of a utility pole
just W of the bedrock.

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

                                                                                
Station ID: 8460751                         PUBLICATION DATE:  06/20/2016
Name:       WEST MYSTIC, MYSTIC RIVER                         
            CT
NOAA Chart: 13214                           Latitude:   41° 20.6' N (  41.34330)
USGS Quad:  Mystic                          Longitude:  71° 58.5' W ( -71.97500)


                            T I D A L   D A T U M S 


Tidal datums at WEST MYSTIC, MYSTIC RIVER based on:

     LENGTH OF SERIES:      4 MONTHS
     TIME PERIOD:           May 2015 - August 2015
     TIDAL EPOCH:           1983-2001
     CONTROL TIDE STATION:  8461490 NEW LONDON, THAMES RIVER


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

     MEAN HIGHER HIGH WATER                     MHHW   =  0.909
     MEAN HIGH WATER                            MHW    =  0.820
     North American Vertical Datum              NAVD88 =  0.565
     MEAN SEA LEVEL                             MSL    =  0.450
     MEAN TIDE LEVEL                            MTL    =  0.439
     MEAN LOW WATER                             MLW    =  0.058
     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 1 1917                                   1.279    0.459
     0751 A 2015                                 1.952    1.132
     HILL 1934                                   7.919    7.099
     HILL NO 1 1934                              5.532    4.712
     HILL NO 2 1934                              5.098    4.278
     V 37 1965                                   9.354    8.534


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

                                                                                
Station ID: 8460751                         PUBLICATION DATE:  06/20/2016
Name:       WEST MYSTIC, MYSTIC RIVER                         
            CT
NOAA Chart: 13214                           Latitude:   41° 20.6' N (  41.34330)
USGS Quad:  Mystic                          Longitude:  71° 58.5' W ( -71.97500)


                             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.