Superseded Bench Mark Sheet for 8443662, AMELIA EARHART DAM, MYSTIC RIVER MA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:  05/10/2000
Station ID: 8443662                                SUPERCEDED DATE:   04/21/2003
Name:       AMELIA EARHART DAM, MYSTIC RIVER                  
            MASSACHUSETTS
NOAA Chart: 13272                                  Latitude:         42° 23.7' N
USGS Quad:  BOSTON NORTH                           Longitude:        71°  4.6' W


To reach the tide station from the Wellington Bridge over the Mystic River,
proceed SSW for 0.3 km (0.2 mi) from the bridge on State Route 28 to the second
traffic light, proceed (left) SSE on Middlesex Street for 0.5 km (0.3 mi) to
Foley Street, then ENE for 0.8 km (0.5 mi) on Foley street to its terminus at
the Draw 7 Park and Amelia Earhart Dam parking lot.  The tide gage and staff
were located on the SE fender of the dam and the tidal bench marks are located
in the vicinity of the dam and the park.


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


                 PRIMARY BENCH MARK STAMPING:  3662 A 1994
                         DESIGNATION:          844 3662 A

MONUMENTATION:           Tidal Station disk                        VM#:    12888
AGENCY:                  National Ocean Service (NOS)              PID:         
SETTING CLASSIFICATION:  Concrete dam


The primary bench mark is a disk set flush in concrete on the SW side of the
Amelia Earhart Dam, 6.00 m (19.7 ft) west of the most SW of four signal lamps at
the SE end of the dam, 5.40 m (17.7 ft) NW of the SE corner of the dam, and 0.50
m (1.6 ft) NE of the SW edge of the dam.



                         BENCH MARK STAMPING:  3662 B 1994
                         DESIGNATION:          844 3662 B

MONUMENTATION:           Tidal Station disk                        VM#:    12889
AGENCY:                  National Ocean Service (NOS)              PID:         
SETTING CLASSIFICATION:  Concrete culvert


The bench mark is a disk set flush on the top of a concrete field drain culvert,
16.79 m (55.1 ft) NE of a fire hydrant near a soccer field, 10.61  m (34.8 ft)
NNW of a manhole cover in the center of nearby blacktop bicycle path, 4.00 m
(13.1 ft) west of the bicycle path, and 1.00 m (3.3 ft) SE of the NW edge of the
culvert.

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

                                                   PUBLICATION DATE:  05/10/2000
Station ID: 8443662                                SUPERCEDED DATE:   04/21/2003
Name:       AMELIA EARHART DAM, MYSTIC RIVER                  
            MASSACHUSETTS
NOAA Chart: 13272                                  Latitude:         42° 23.7' N
USGS Quad:  BOSTON NORTH                           Longitude:        71°  4.6' W


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


                         BENCH MARK STAMPING:  3662 C 1994
                         DESIGNATION:          844 3662 C

MONUMENTATION:           Tidal Station disk                        VM#:    12890
AGENCY:                  National Ocean Service (NOS)              PID:         
SETTING CLASSIFICATION:  Bridge pier


The bench mark is a disk set flush in the third north concrete pier from the
southern end of an elevated train bridge crossing the Mystic River just SE of
the dam, 5.00 m (16.4 ft) west of the east edge of the pier, 1.71 m (5.6 ft)
south of the north edge of pier, 0.30 m (1.0 ft) east of the west edge of pier,
and is 0.80 m (2.6 ft) above the ground.



                         BENCH MARK STAMPING:  3662 D 1994
                         DESIGNATION:          844 3662 D

MONUMENTATION:           Tidal Station disk                        VM#:    12891
AGENCY:                  National Ocean Service (NOS)              PID:         
SETTING CLASSIFICATION:  Concrete abutment


The bench mark is a disk set flush in concrete abutment at the SW end of a train
threstle, 23.10 m (75.8 ft) SE of telephone light pole No 577-10-2, 1.71 m (5.6
ft) south of the north edge of concrete abutment, 0.30 m (1.0 ft) ESE of the
west edge of abutment, and 1.10 m (3.6 ft) above ground.

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

                                                   PUBLICATION DATE:  05/10/2000
Station ID: 8443662                                SUPERCEDED DATE:   04/21/2003
Name:       AMELIA EARHART DAM, MYSTIC RIVER                  
            MASSACHUSETTS
NOAA Chart: 13272                                  Latitude:         42° 23.7' N
USGS Quad:  BOSTON NORTH                           Longitude:        71°  4.6' W


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


                         BENCH MARK STAMPING:  3662 E 1994
                         DESIGNATION:          844 3662 E

MONUMENTATION:           Tidal Station disk                        VM#:    12892
AGENCY:                  National Ocean Service (NOS)              PID:         
SETTING CLASSIFICATION:  Concrete dam


The bench mark is a disk set flush in concrete foundation of east pumping
station for the Amelia Earhart Dam, located 37.40 m (122.7 ft) NE of the SW
corner of the Pump Building, 13.41 m (44.0 ft) ESE of the NW edge of station
intake, 2.59 m (8.5 ft) south of the north edge of concrete  foundation, and
0.40 m (1.3 ft) NW of the NW face of pumping station.

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

                                                   PUBLICATION DATE:  05/10/2000
Station ID: 8443662                                SUPERCEDED DATE:   04/21/2003
Name:       AMELIA EARHART DAM, MYSTIC RIVER                  
            MASSACHUSETTS
NOAA Chart: 13272                                  Latitude:         42° 23.7' N
USGS Quad:  BOSTON NORTH                           Longitude:        71°  4.6' W


                            T I D A L   D A T U M S 


Tidal datums at AMELIA EARHART DAM, MYSTIC RIVER based on:

     LENGTH OF SERIES:      157 HW and 157 LW
     TIME PERIOD:           May 4, 1994 - July 23, 1994
     TIDAL EPOCH:           1960-1978
     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   =  3.167
     MEAN HIGH WATER                            MHW    =  3.033
     MEAN SEA LEVEL                             MSL    =  1.606
     MEAN TIDE LEVEL                            MTL    =  1.570
     MEAN LOW WATER                             MLW    =  0.104
     MEAN LOWER LOW WATER                       MLLW   =  0.000



Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MLLW        MHW

     3662 A 1994                                 5.337    2.305
     3662 B 1994                                 4.727    1.694
     3662 C 1994                                 4.837    1.804
     3662 D 1994                                 5.844    2.811
     3662 E 1994                                 5.443    2.410


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

                                                   PUBLICATION DATE:  05/10/2000
Station ID: 8443662                                SUPERCEDED DATE:   04/21/2003
Name:       AMELIA EARHART DAM, MYSTIC RIVER                  
            MASSACHUSETTS
NOAA Chart: 13272                                  Latitude:         42° 23.7' N
USGS Quad:  BOSTON NORTH                           Longitude:        71°  4.6' 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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