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Bench Mark Sheet for 8464255, ROCKY HILL,CONNECTICUT RIVER CT

Superseded Epoch

Large map location marker Station Location
Small red map location marker Published bench mark
Small blue map location marker Unpublished bench mark

Bench mark positions only appear on the map if their coordinates in the CO-OPS database are at the precision of degrees/minutes/seconds/and tenths of seconds. If the coordinates are less precise, the mark will not appear.

Printable version

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
Datums Page                                                        Page  1 of  5

                                                                                
Station ID: 8464255                         PUBLICATION DATE:  05/16/2003
Name:       ROCKY HILL,CONNECTICUT RIVER                      
            CT
NOAA Chart: 12377                           Latitude:   41° 39.8' N (  41.66330)
USGS Quad:  HARTFORD SOUTH                  Longitude:  72° 37.8' W ( -72.63000)


To reach the tidal bench marks from Middleton proceed north on State Road 99 to
Rocky Hill Fire Department Company #3, turn right on Old Forge Road and go 1.21
km (0.75 mi) to Dividend Road, turn left on Dividend Road and go 0.3 km (0.2 mi)
to Evans Road, turn right on Evans Road and go 0.40 km (0.25 mi) to Rocky Hill
Oil Company.  The bench marks are on the oil company property and along the
railroad tracks.  The tide gage and staff were on the south side of the oil
company fuel transfer dock behind the company grounds, reached through a locked
company gate leading to the dock.


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


                 PRIMARY BENCH MARK STAMPING:  1 1938
                         DESIGNATION:          846 4255 TIDAL 1

MONUMENTATION:           Tidal Station disk                    VM#:         2257
AGENCY:                  US Coast and Geodetic Survey
                         (USC&GS)                              IDB PID#:        
SETTING CLASSIFICATION:  Concrete pump house                   OPUS PID:        
LATITUDE:   41° 39.0' N (  41.65000)          LONGITUDE:  72° 37.6' W ( -72.62670)


The primary bench mark is a disk set in the top of a 2.19 m (7.2 ft) square
abandoned concrete pump house, 18 m (60 ft) north of the oil company fuel
transfer dock, 5.09 m (16.7 ft) east of the river front fence on company
grounds, 9 m (30 ft) south of the SE corner of a masonry building, and 3 m (9
ft) below the base of the fence.

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

                                                                                
Station ID: 8464255                         PUBLICATION DATE:  05/16/2003
Name:       ROCKY HILL,CONNECTICUT RIVER                      
            CT
NOAA Chart: 12377                           Latitude:   41° 39.8' N (  41.66330)
USGS Quad:  HARTFORD SOUTH                  Longitude:  72° 37.8' W ( -72.63000)


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


                         BENCH MARK STAMPING:  2 1938
                         DESIGNATION:          846 4255 TIDAL 2

MONUMENTATION:           Tidal Station disk                    VM#:         2258
AGENCY:                  US Coast and Geodetic Survey
                         (USC&GS)                              IDB PID#:        
SETTING CLASSIFICATION:  Concrete railroad overpass            OPUS PID:        
LATITUDE:   41° 39.0' N (  41.65000)          LONGITUDE:  72° 37.6' W ( -72.62670)


The bench mark is a disk set in the NE corner of the concrete railroad overpass
at the company entrance gate, 26 m (84 ft) south of a 2 m (6 ft) high Close
Clearance sign which is 2 m (6 ft) west of the railroad, 24.17 m (79.3 ft) south
of a 1 m (2 ft) high rail post which is 2 m (6 ft) west of the railroad, and
1.10 m (3.6 ft) east of the east rail.



                         BENCH MARK STAMPING:  3 1938
                         DESIGNATION:          846 4255 TIDAL 3

MONUMENTATION:           Tidal Station disk                    VM#:         2259
AGENCY:                  US Coast and Geodetic Survey
                         (USC&GS)                              IDB PID#:        
SETTING CLASSIFICATION:  Concrete base                         OPUS PID:        
LATITUDE:   41° 39.0' N (  41.65000)          LONGITUDE:  72° 37.6' W ( -72.62670)


The bench mark is a disk set in the SW corner of a 0.85 m (2.8 ft) square
abandoned concrete railroad signal base, 138 ties north along the railroad from
the centerline of Evans Road, 2 m (8 ft) west of the west rail, and 0.24 m (0.8
ft) above ground level.

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

                                                                                
Station ID: 8464255                         PUBLICATION DATE:  05/16/2003
Name:       ROCKY HILL,CONNECTICUT RIVER                      
            CT
NOAA Chart: 12377                           Latitude:   41° 39.8' N (  41.66330)
USGS Quad:  HARTFORD SOUTH                  Longitude:  72° 37.8' W ( -72.63000)


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


                         BENCH MARK STAMPING:  4255 D 1987
                         DESIGNATION:          846 4255 D

MONUMENTATION:           Tidal Station disk                    VM#:         2260
AGENCY:                  National Ocean Service (NOS)          IDB PID#:        
SETTING CLASSIFICATION:  Concrete catch basin                  OPUS PID:        
LATITUDE:   41° 39.0' N (  41.65000)          LONGITUDE:  72° 37.6' W ( -72.62670)


The bench mark is a disk set flush in the top of a concrete catch basin north of
the south intersection of an inner spur pair of rails off the main line, SE of
the building at 51 Belamose Avenue, 85 m (280 ft) north of the south
intersection of the inner pair of rails, 4.82 m (15.8 ft) west of the west rail
of the east pair of rails, and 3.08 m (10.1 ft) east of the east rail of the
west pair of rails.



                         BENCH MARK STAMPING:  4255 E 1987
                         DESIGNATION:          846 4255 E

MONUMENTATION:           Tidal Station disk                    VM#:         2261
AGENCY:                  National Ocean Service (NOS)          IDB PID#:        
SETTING CLASSIFICATION:  Concrete stairway                     OPUS PID:        
LATITUDE:   41° 39.0' N (  41.65000)          LONGITUDE:  72° 37.6' W ( -72.62670)


The bench mark is a disk set in the outside end of the lowest step of an outside
concrete stairway at 51 Belamose Avenue, 41.24 m (135.3 ft) west of the west
rail of a railroad track which intersects Belamose Avenue and passes east of 51
Belamose Avenue, 29.20 m (95.8 ft) along the east wall from the NE corner of 51
Belamose Avenue, and 2.01 m (6.6 ft) north of the SE corner of the easternmost
wall of the building.

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

                                                                                
Station ID: 8464255                         PUBLICATION DATE:  05/16/2003
Name:       ROCKY HILL,CONNECTICUT RIVER                      
            CT
NOAA Chart: 12377                           Latitude:   41° 39.8' N (  41.66330)
USGS Quad:  HARTFORD SOUTH                  Longitude:  72° 37.8' W ( -72.63000)


                            T I D A L   D A T U M S 


Tidal datums at ROCKY HILL,CONNECTICUT RIVER based on:

     LENGTH OF SERIES:      4 MONTHS
     TIME PERIOD:           June 1987 - September 1987
     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   =  0.689
     MEAN HIGH WATER                            MHW    =  0.611
     MEAN SEA LEVEL                             MSL    =  0.335
     MEAN TIDE LEVEL                            MTL    =  0.325
     MEAN LOW WATER                             MLW    =  0.038
     MEAN LOWER LOW WATER                       MLLW   =  0.000

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MLLW        MHW

     1 1938                                      7.217    6.606
     2 1938                                     13.544   12.933
     3 1938                                     14.247   13.636
     4255 D 1987                                11.093   10.482
     4255 E 1987                                 9.581    8.970


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

                                                                                
Station ID: 8464255                         PUBLICATION DATE:  05/16/2003
Name:       ROCKY HILL,CONNECTICUT RIVER                      
            CT
NOAA Chart: 12377                           Latitude:   41° 39.8' N (  41.66330)
USGS Quad:  HARTFORD SOUTH                  Longitude:  72° 37.8' W ( -72.63000)


                             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.

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Products available at 8464255 ROCKY HILL,CONNECTICUT RIVER, CT

Revised: 08/08/2018
NOAA / National Ocean Service
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