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Station ID: 8419317 SUPERCEDED DATE: 04/21/2003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Station ID: 8419317 SUPERCEDED DATE: 04/21/2003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.