Superseded Bench Mark Sheet for 8452154, Bristol Highlands RI

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:  11/19/1985
Station ID: 8452154                                SUPERCEDED DATE:   04/21/2003
Name:       BRISTOL HIGHLANDS, NARRAGANSETT BAY               
            RHODE ISLAND
NOAA Chart: 13221                                  Latitude:         41° 41.8' N
USGS Quad:  BRISTOL                                Longitude:        71° 17.6' W


To reach the tidal bench marks from Bristol, proceed north 3 miles (5 km) on
State Route 114 to Gibson Road, turn left (west) onto Gibson Road and travel 1
mile (2 km) until the road ends in a small park owned by Bristol Highlands
Improvement Association (BHIA).  The bench marks are mounted in the concrete
seawall at the east end of the pier and extend south along the seawall and east
toward the pavilion.  The tide gauge and staff were on the north side of the
pier.


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


                 PRIMARY BENCH MARK STAMPING:  2154 A 1977

MONUMENTATION:           Survey Disk                               VM#:     2159
AGENCY:                                                            PID:         
SETTING CLASSIFICATION:  Concrete Seawall


The bench mark is set flush in the top of the northernmost end of a north-south
concrete seawall within the BHIA park, 115.5 feet (35.2 m) west of a 5-foot (2
m) high stone and cement column set in the fence along the east side of the
park, 76.8 feet (23.4 m) SW of the SW corner of the park, and 61 feet (19 m)
north of the centerline of the concrete steps in the seawall, which lead to the
beach.



                         BENCH MARK STAMPING:  2154 B 1977

MONUMENTATION:           Survey Disk                               VM#:     2160
AGENCY:                                                            PID:         
SETTING CLASSIFICATION:  Concrete Seawall


The bench mark is set flush in the top of the north-south concrete seawall
within the BHIA park, 124.5 feet (37.9 m) west of the centerline of the road
paralleling the shoreline on the east side of the park, 45 feet (14 m) NW of
Bench Mark 2154 C 1977, 41 feet (12 m) south of Bench Mark 2154 A 1977, 25 feet
(8 m) NW of the NW corner of a cement and wood pavilion in the center of the
park, and 20 feet (6 m) north of the centerline of the concrete steps in the
seawall, which lead to the beach.

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

                                                   PUBLICATION DATE:  11/19/1985
Station ID: 8452154                                SUPERCEDED DATE:   04/21/2003
Name:       BRISTOL HIGHLANDS, NARRAGANSETT BAY               
            RHODE ISLAND
NOAA Chart: 13221                                  Latitude:         41° 41.8' N
USGS Quad:  BRISTOL                                Longitude:        71° 17.6' W


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


                         BENCH MARK STAMPING:  2154 C 1977

MONUMENTATION:           Survey Disk                               VM#:     2161
AGENCY:                                                            PID:         
SETTING CLASSIFICATION:  Concrete Foundation


The bench mark is set flush in the SE corner of the cement foundation of a
pavilion having 4 steel columns supporting a wooden roof in the center of the
BHIA park, 83 feet (25 m) WNW of the center of a large 8-foot (2 m) high stone
and cement column, located at the junction of Gibson Road and the road
paralleling the shoreline and the east side of the park, 45 feet (14 m) SE of
Bench Mark 2154 B 1977, and 37 feet (11 m) east of the concrete seawall.



                         BENCH MARK STAMPING:  2154 D 1977

MONUMENTATION:           Survey Disk                               VM#:     2162
AGENCY:                                                            PID:         
SETTING CLASSIFICATION:  Concrete Seawall


The bench mark is located where the seawall begins to curve to the SW, set flush
in the top of the north-south concrete seawall within the BHIA park, 55 feet (17
m) SW of Bench Mark 2154 C 1977, 43.5 feet (13.3 m) NNW of the Bench Mark 2154 E
1977, 38 feet (12 m) south of the centerline of the steps leading to the beach,
in the seawall, and 22.5 feet (7 m) SW of the SW corner of the pavilion in the
center of the park.

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

                                                   PUBLICATION DATE:  11/19/1985
Station ID: 8452154                                SUPERCEDED DATE:   04/21/2003
Name:       BRISTOL HIGHLANDS, NARRAGANSETT BAY               
            RHODE ISLAND
NOAA Chart: 13221                                  Latitude:         41° 41.8' N
USGS Quad:  BRISTOL                                Longitude:        71° 17.6' W


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


                         BENCH MARK STAMPING:  2154 E 1977

MONUMENTATION:           Survey Disk                               VM#:     2163
AGENCY:                                                            PID:         
SETTING CLASSIFICATION:  Concrete Seawall


The bench mark is set flush in the top of the southernmost end of a concrete
seawall within the BHIA park, 81 feet (25 m) SE of the centerline of the steps
in the seawall which lead to the beach, 32 feet (10 m) north of the centerline
of a boat ramp at the south end of the park, and 13.5 feet (4.1 m) SE of the
junction of the NW-SE seawall and the north-south seawall.

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

                                                   PUBLICATION DATE:  11/19/1985
Station ID: 8452154                                SUPERCEDED DATE:   04/21/2003
Name:       BRISTOL HIGHLANDS, NARRAGANSETT BAY               
            RHODE ISLAND
NOAA Chart: 13221                                  Latitude:         41° 41.8' N
USGS Quad:  BRISTOL                                Longitude:        71° 17.6' W


                            T I D A L   D A T U M S 


Tidal datums at BRISTOL HIGHLANDS, NARRAGANSETT BAY based on:

     LENGTH OF SERIES:      52 HIGHS &  LOWS
     TIME PERIOD:           OCTOBER 19 - NOVEMBER 15, 1977
     TIDAL EPOCH:           1960-1978
     CONTROL TIDE STATION:  8454000 NEWPORT


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

     HIGHEST OBSERVED WATER LEVEL (11/11/1977)         =   6.88
     MEAN HIGHER HIGH WATER                     MHHW   =   4.66
     MEAN HIGH WATER                            MHW    =   4.41
     MEAN TIDE LEVEL                            MTL    =   2.29
     MEAN LOW WATER                             MLW    =   0.17
     MEAN LOWER LOW WATER                       MLLW   =   0.00
     LOWEST  OBSERVED WATER LEVEL (11/12/1977)         =  -0.85



Bench Mark Elevation Information                In FEET above:

     Stamping or Designation                    MLLW        MHW

     2154 A 1977                                 5.86      1.45
     2154 B 1977                                 5.88      1.47
     2154 C 1977                                 9.19      4.78
     2154 D 1977                                 5.63      1.22
     2154 E 1977                                 6.82      2.41


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

                                                   PUBLICATION DATE:  11/19/1985
Station ID: 8452154                                SUPERCEDED DATE:   04/21/2003
Name:       BRISTOL HIGHLANDS, NARRAGANSETT BAY               
            RHODE ISLAND
NOAA Chart: 13221                                  Latitude:         41° 41.8' N
USGS Quad:  BRISTOL                                Longitude:        71° 17.6' 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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