NOAA Web Site Link Tides and Currents Home Page Transparent placeholder image

Bench Mark Sheet for 8455189, Westerly Pawcatuck RI

Superseded Epoch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Small blue map location marker Unpublished bench mark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  6

                                                                                
Station ID: 8455189                         PUBLICATION DATE:  06/20/2016
Name:       WESTERLY, PAWCATUCK RIVER                         
            RI
NOAA Chart: 13214                           Latitude:   41° 22.9' N (  41.38170)
USGS Quad:  WATCH HILL                      Longitude:  71° 49.9' W ( -71.83170)


To reach the tidal bench marks from the intersection of U.S. Highway 1 (Broad
Street) and Main Street, proceed south on Main Street for 1.0 km (0.6 mi) to a
fork in the road at Margin Street and Beach Street, continue right on Margin
Street and proceed80 m (250 ft) south to number 4 Margin Street.  The bench
marks are located along the east side of the Pawcatuck River between 4 Margin
Drive and the Canal Street railroad overpass north of downtown Westerly.  The
tide gauge is located on the south side of the pier at 4 Margin Street.


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


                 PRIMARY BENCH MARK STAMPING:  A 18 1965
                         DESIGNATION:          A 18

MONUMENTATION:           Bench Mark disk                       VM#:        21485
AGENCY:                  US Coast & Geodetic Survey            IDB PID#:  LW0745
SETTING CLASSIFICATION:  Retaining wall                        OPUS PID#: LW0745
LATITUDE:   41° 22.6' N (  41.37750)          LONGITUDE:  71° 49.9' W ( -71.83144)


The primary bench mark is a disk set on top of a concrete retaining wall for the
U.S. highway 1 bridge over the Pawcatuck river, 38.45 m (126.1 ft) NNE of the S
end of a 0.84 m (2.8 ft) tall retaining wall bordering a parking lot and the
river, 23.61 m (77.5 ft) NNW of the third decorative lamppost S of the westerly
bridge, 17.32 m (56.8 ft) WNW of the W curb edge of main street, 15.69 m (51.5
ft) SW of the end of the SE bridge parapet, 9.93 m (32.6 ft) WSW of the S of
three flag poles, 6.83 m (22.4 ft) WSW of the SW corner of the Korean war
memorial wall and about 3.40 m (11.2 ft) above the retaining wall footing in the
river.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  2 of  6

                                                                                
Station ID: 8455189                         PUBLICATION DATE:  06/20/2016
Name:       WESTERLY, PAWCATUCK RIVER                         
            RI
NOAA Chart: 13214                           Latitude:   41° 22.9' N (  41.38170)
USGS Quad:  WATCH HILL                      Longitude:  71° 49.9' W ( -71.83170)


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


                         BENCH MARK STAMPING:  NO 1 1917 4.656 FT
                         DESIGNATION:          845 5189 TIDAL 1

MONUMENTATION:           Tidal Station disk                    VM#:         2215
AGENCY:                  US Coast and Geodetic Survey
                         (USC&GS)                              IDB PID#:  LW0747
SETTING CLASSIFICATION:  Stone walkway                         OPUS PID:        
LATITUDE:   41° 22.2' N (  41.36939)          LONGITUDE:  71° 49.9' W ( -71.83203)


The bench mark is a disk set in a 1.10 m (3.6 ft) by 0.90 m (3.0 ft) stone
sidewalk slab leading to the pier, 27.23 m (89.3 ft) WSW of a utility pole
numbered 26, 25.00 m (82.0 ft) N of the high point of the S most granite
driveway entrance monolith, 4.48 m (14.7 ft) ESE of the river side edge of a
stone retaining wall bordering the Pawcatuck River, 3.54 m (11.6 ft) NW of the
curb edge of margin drive, 0.36 m (1.2 ft) WSW of the NE corner of the bottom of
the steps and about 1.60 m (5.2 ft) lower than the road.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  3 of  6

                                                                                
Station ID: 8455189                         PUBLICATION DATE:  06/20/2016
Name:       WESTERLY, PAWCATUCK RIVER                         
            RI
NOAA Chart: 13214                           Latitude:   41° 22.9' N (  41.38170)
USGS Quad:  WATCH HILL                      Longitude:  71° 49.9' W ( -71.83170)


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


                         BENCH MARK STAMPING:  BM B 1 1961
                         DESIGNATION:          B 1

MONUMENTATION:           Bench Mark disk                       VM#:         2217
AGENCY:                  US Coast and Geodetic Survey
                         (USC&GS)                              IDB PID#:  LW0746
SETTING CLASSIFICATION:  Stone retaining wall                  OPUS PID:        
LATITUDE:   41° 22.2' N (  41.36983)          LONGITUDE:  71° 49.9' W ( -71.83167)


The bench mark is a disk set in a 0.40 m (1.3 ft) by 2.73 m (9.0 ft) by 0.20 m
(0.7 ft) capstone to a retaining wall along the E bank of the Pawcatuck River on
the property of 2 margin street, 23.54 m (77.2 ft) W of the top bolt of a fire
hydrant, 19.53 m (64.1 ft) WSW of a utility pole numbered 25, 19.36 m (63.5 ft)
NNW of a concrete monument S of a driveway for 2 margin street, 11.82 m (38.8
ft) NW of the center line of margin road and about 1.40 m (4.6 ft) above the
river bottom.



                         BENCH MARK STAMPING:  5189 A 2015
                         DESIGNATION:          845 5189 A

MONUMENTATION:           Tidal Station disk                    VM#:        21486
AGENCY:                  National Ocean Service                IDB PID#:        
SETTING CLASSIFICATION:  Catch basin with wing wall            OPUS PID:        
LATITUDE:   41° 22.5' N (  41.37500)          LONGITUDE:  71° 49.9' W ( -71.83214)


The bench mark is a disk set in a catch basin with a wing wall at the boat
launch ramp, 15.87 m (52.1 ft) E of the SW most piling in the river, 15.62 m
(51.2 ft) SW of the S post of a fishing area sign, 7.70 m (25.3 ft) N of the S
edge of the catch basin, 4.34 m (14.2 ft) SSE of the SW corner of a square storm
drain, 0.55 m (1.8 ft) SE of the face of the NE most piling with a hand rail and
0.18 m (0.6 ft) E of the drain strip in the catch basin.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  4 of  6

                                                                                
Station ID: 8455189                         PUBLICATION DATE:  06/20/2016
Name:       WESTERLY, PAWCATUCK RIVER                         
            RI
NOAA Chart: 13214                           Latitude:   41° 22.9' N (  41.38170)
USGS Quad:  WATCH HILL                      Longitude:  71° 49.9' W ( -71.83170)


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


                         BENCH MARK STAMPING:  G 18 1965
                         DESIGNATION:          G 18

MONUMENTATION:           Bench Mark disk                       VM#:        21487
AGENCY:                  US Coast & Geodetic Survey            IDB PID#:  LW0750
SETTING CLASSIFICATION:  Railroad bridge abutment              OPUS PID:        
LATITUDE:   41° 22.8' N (  41.38075)          LONGITUDE:  71° 49.8' W ( -71.83067)


The bench mark is a disk set vertically in the wing wall of a rail road overpass
spanning canal street, 26.51 m (87.0 ft) SE of a power pole W of the underpass
numbered 44, 11.55 m (37.9 ft) SSW of the top of the stairs (slant distance),
10.65 m (34.9 ft) NW of a 0.35 m (1.1 ft) by 0.17 m (0.6 ft) plaque in memory of
Anthony J Perrone, 8.16 m (26.8 ft) NW of a utility pole E of the underpass
numbered 45, 8.13 m (26.7 ft) NE of the centerline of canal street, 0.45 m (1.5
ft) NE of the S end of the bridge wing wall, and set vertically in the SE face
of the wing wall about 0.90 m (3.0 ft) higher than the sidewalk.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  5 of  6

                                                                                
Station ID: 8455189                         PUBLICATION DATE:  06/20/2016
Name:       WESTERLY, PAWCATUCK RIVER                         
            RI
NOAA Chart: 13214                           Latitude:   41° 22.9' N (  41.38170)
USGS Quad:  WATCH HILL                      Longitude:  71° 49.9' W ( -71.83170)


                            T I D A L   D A T U M S 


Tidal datums at WESTERLY, PAWCATUCK 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   =  0.973
     MEAN HIGH WATER                            MHW    =  0.883
     North American Vertical Datum              NAVD88 =  0.572
     MEAN SEA LEVEL                             MSL    =  0.474
     MEAN TIDE LEVEL                            MTL    =  0.472
     MEAN LOW WATER                             MLW    =  0.061
     MEAN LOWER LOW WATER                       MLLW   =  0.000

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MLLW        MHW

     A 18 1965                                   4.127    3.244
     NO 1 1917 4.656 FT                          1.684    0.801
     BM B 1 1961                                 1.504    0.621
     5189 A 2015                                 1.534    0.651
     G 18 1965                                   6.600    5.717


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

                                                                                
Station ID: 8455189                         PUBLICATION DATE:  06/20/2016
Name:       WESTERLY, PAWCATUCK RIVER                         
            RI
NOAA Chart: 13214                           Latitude:   41° 22.9' N (  41.38170)
USGS Quad:  WATCH HILL                      Longitude:  71° 49.9' W ( -71.83170)


                             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.

Return to Top
Products available at 8455189 Westerly Pawcatuck, RI

Revised: 08/08/2018
NOAA / National Ocean Service
Web site owner: Center for Operational Oceanographic Products and Services