Superseded Bench Mark Sheet for 8419317, Wells ME

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:  04/17/2000
Station ID: 8419317                                SUPERCEDED DATE:   04/21/2003
Name:       WELLS, WEBHANNET RIVER                            
            MAINE
NOAA Chart: 13286                                  Latitude:         43° 19.2' N
USGS Quad:  WELLS                                  Longitude:        70° 33.8' W


To reach the bench marks from the intersection of US Route 1 and State Route 9
in Wells, proceed north on Route 1 for 45.7 m (150 ft) to Lower Landing Road and
proceed east for 1.6 km (1.0 mi) to the Wells Town Dock. The bench marks are
along Lower Landing Road, Route 9, and Route 1. The tide gage is located on the
town dock.


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


                 PRIMARY BENCH MARK STAMPING:  PUMP 1987
                         DESIGNATION:          841 9317 PUMP

MONUMENTATION:           Survey disk                               VM#:    15919
AGENCY:                  US Army Corps of Engineers (COE)          PID:         
SETTING CLASSIFICATION:  Concrete pad


The primary bench mark is a disk set in the east corner of a concrete pad at the
entrance to the pump station next to Lords Harbor Restaurant, 72 m (236 ft) 
north of the centerline of Lower Landing Road, 12.88 m (42.3 ft) north of a
utility pole numbered  DC-C7, and  5.46 m (17.9 ft) NE of the center of the
circular concrete pad.



                         BENCH MARK STAMPING:  9317 A 1999
                         DESIGNATION:          841 9317 A

MONUMENTATION:           Tidal Station disk                        VM#:    15920
AGENCY:                  National Ocean Service (NOS)              PID:         
SETTING CLASSIFICATION:  Concrete skidway


The bench mark is a disk set in the concrete skidway at Webhannet River
Boatyard, 13.44 M (44.1 ft) east of the NE corner of the Webhannet River
Boatyard building, 5.72 m (18.8 ft) south of the SE corner of the Webhannet
River Boat Supply Shop, and 0.29 m (0.1 ft) SE of the NW edge of the concrete
skidway at the boatyard.

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

                                                   PUBLICATION DATE:  04/17/2000
Station ID: 8419317                                SUPERCEDED DATE:   04/21/2003
Name:       WELLS, WEBHANNET RIVER                            
            MAINE
NOAA Chart: 13286                                  Latitude:         43° 19.2' N
USGS Quad:  WELLS                                  Longitude:        70° 33.8' W


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


                         BENCH MARK STAMPING:  TBM SLAB 1987
                         DESIGNATION:          841 9317 TBM SLAB

MONUMENTATION:           Survey disk                               VM#:    15921
AGENCY:                  US Army Corps of Engineers (COE)          PID:         
SETTING CLASSIFICATION:  Concrete slab


The bench mark is a disk set in the  concrete slab at the entrance to the Wells
Town Dock, 8.36 m (27.4 ft) north of the NW corner of the Wells Harbormaster
building, 4.87 m (15.9 ft) south of the SW corner of a small wood frame
building, and 2.76 m (9.1 ft) NW of the NE corner of the concrete pad.



                         BENCH MARK STAMPING:  LORD 1975
                         DESIGNATION:          LORD

MONUMENTATION:           Survey disk                               VM#:    15922
AGENCY:                  Maine DOT                                 PID#:  OC2106
SETTING CLASSIFICATION:  Concrete monument


The bench mark is a disk set in a concrete post located 0.8 km (0.5 mi) ESE
along Lower Landing Road from its intersection with U.S. Highway 1, 11.80 m
(38.7 ft) west of power pole numbered 20, 11.40 m (37.4 ft) north of a cable
pole, 11 m (35 ft)  SSW of the Lower Landing Road centerline, and 1m (3ft) below
the surface of the road.

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

                                                   PUBLICATION DATE:  04/17/2000
Station ID: 8419317                                SUPERCEDED DATE:   04/21/2003
Name:       WELLS, WEBHANNET RIVER                            
            MAINE
NOAA Chart: 13286                                  Latitude:         43° 19.2' N
USGS Quad:  WELLS                                  Longitude:        70° 33.8' W


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


                         BENCH MARK STAMPING:  A 161 1966
                         DESIGNATION:          A 161

MONUMENTATION:           Bench Mark disk                           VM#:    15923
AGENCY:                  Coast and Geodetic Survey (USC&GS)        PID#:  OC0367
SETTING CLASSIFICATION:  Concrete wing wall


The bench mark is a disk set in the top of the SE concrete wing wall for a pipe
culvert located 0.08 km (0.05 mi) along State Highway 9 from its intersection
with U.S. Highway 1, 11 m (35 ft) south of the center line of US Highway 9, and
1.07 m (3.5 ft) north of the sound end of the wing wall.



                         BENCH MARK STAMPING:  B 161 1966
                         DESIGNATION:          B 161

MONUMENTATION:           Bench Mark disk                           VM#:    15924
AGENCY:                  Coast and Geodetic Survey (USC&GS)        PID#:  OC0368
SETTING CLASSIFICATION:  Concrete wing wall


The bench mark is a disk set in the north concrete wing wall for a 3 m (9 ft)
box culvert over Depot Brook located 0.2 km (0.1 mi) NE along U.S. Highway 1
from its intersection with State Highway 9, 7 m (23 ft) NW of the center line of
Highway 1, and 0.3 m (1 ft) below the level of the highway.

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

                                                   PUBLICATION DATE:  04/17/2000
Station ID: 8419317                                SUPERCEDED DATE:   04/21/2003
Name:       WELLS, WEBHANNET RIVER                            
            MAINE
NOAA Chart: 13286                                  Latitude:         43° 19.2' N
USGS Quad:  WELLS                                  Longitude:        70° 33.8' W


                            T I D A L   D A T U M S 


Tidal datums at WELLS, WEBHANNET RIVER based on:

     LENGTH OF SERIES:      1 MONTHS
     TIME PERIOD:           July 1999 - July 1999
     TIDAL EPOCH:           1960-1978
     CONTROL TIDE STATION:  8418150 PORTLAND, CASCO BAY


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

     MEAN HIGHER HIGH WATER                     MHHW   =  2.909
     MEAN HIGH WATER                            MHW    =  2.778
     North American Vertical Datum              NAVD88 =  1.532
     MEAN SEA LEVEL                             MSL    =  1.451
     MEAN TIDE LEVEL                            MTL    =  1.438
     MEAN LOW WATER                             MLW    =  0.098
     MEAN LOWER LOW WATER                       MLLW   =  0.000

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MLLW        MHW

     PUMP 1987                                   5.534    2.756
     9317 A 1999                                 5.157    2.379
     TBM SLAB 1987                               4.692    1.915
     LORD 1975                                   3.994    1.216
     A 161 1966                                 22.386   19.608
     B 161 1966                                 20.559   17.781


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

                                                   PUBLICATION DATE:  04/17/2000
Station ID: 8419317                                SUPERCEDED DATE:   04/21/2003
Name:       WELLS, WEBHANNET RIVER                            
            MAINE
NOAA Chart: 13286                                  Latitude:         43° 19.2' N
USGS Quad:  WELLS                                  Longitude:        70° 33.8' 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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