U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 5
Station ID: 8443187 PUBLICATION DATE: 04/21/2003
Name: LYNN
MA
NOAA Chart: 13275 Latitude: 42° 27.5' N ( 42.45830)
USGS Quad: Lynn Longitude: 70° 56.6' W ( -70.94330)
To reach the tidal bench marks from Lynn City Hall at the intersection of South
Common and Market Streets, proceed south on Market Street for 0.6 km (0.4 mi) to
Carroll Parkway, then east on Carroll Parkway for 0.3 km (0.2 mi) to Seaport
Landing. The bench marks are near Seaport Landing and Lynn-Heritage State
Park. The tide gauge and staff were inside the east access gate to the boat
docks.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 3187 A 1992
DESIGNATION: 844 3187 A
MONUMENTATION: Tidal Station disk VM#: 12087
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete sea wall OPUS PID#: BBCF96
LATITUDE: 42° 27.5' N ( 42.45830) LONGITUDE: 70° 56.6' W ( -70.94330)
The primary bench mark is a disk set in the east end of the sea wall located
near the east access gate to the boat docks, 26.52 m (87.0 ft) SW of the SW
corner of the condominiums, 13.26 m (43.5 ft) NNE of the east access gate, 1.55
m (5.1 ft) south of the southernmost bike lockup rack, and level with the
ground.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 5
Station ID: 8443187 PUBLICATION DATE: 04/21/2003
Name: LYNN
MA
NOAA Chart: 13275 Latitude: 42° 27.5' N ( 42.45830)
USGS Quad: Lynn Longitude: 70° 56.6' W ( -70.94330)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 3187 B 1992
DESIGNATION: 844 3187 B
MONUMENTATION: Tidal Station disk VM#: 12088
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete wing wall OPUS PID:
LATITUDE: 42° 27.5' N ( 42.45830) LONGITUDE: 70° 56.6' W ( -70.94330)
The bench mark is a disk set in the NE corner of the wingwall of the stairs in
front of the Harbormasters office, 18.17 m (59.6 ft) NNW of the west access gate
to the boat docks, 5.49 m (18.0 ft) NNE of the sea wall, 4.88 m (16.0 ft) SE of
the door to the Harbormasters office, and level with the deck.
BENCH MARK STAMPING: 3187 C 1992
DESIGNATION: 844 3187 C
MONUMENTATION: Tidal Station disk VM#: 12089
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete pad OPUS PID:
LATITUDE: 42° 27.5' N ( 42.45830) LONGITUDE: 70° 56.6' W ( -70.94330)
The bench mark is a disk set in the concrete pad located between the two garage
doors on the west side of the building at 154 Seaport Landing, 10.52 m (34.5 ft)
SE of the steel door to the generator room, 2.56 m (8.4 ft) ENE of the card
access reader to the garage, 0.40 m (1.3 ft) SW of the west wall of the
building, and 0.21 m (0.7 ft) above the road.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 5
Station ID: 8443187 PUBLICATION DATE: 04/21/2003
Name: LYNN
MA
NOAA Chart: 13275 Latitude: 42° 27.5' N ( 42.45830)
USGS Quad: Lynn Longitude: 70° 56.6' W ( -70.94330)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 3187 D 1992
DESIGNATION: 844 3187 D
MONUMENTATION: Tidal Station disk VM#: 12090
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete retaining wall OPUS PID:
LATITUDE: 42° 27.5' N ( 42.45830) LONGITUDE: 70° 56.6' W ( -70.94330)
The bench mark is a disk set in the dogleg bend of the retaining wall of a storm
drain outlet in the west end of Lynn-Heritage State Park, 22.40 m (73.5 ft) west
of the west end of the parking lot, 16.55 m (54.3 ft) south of the south end of
the Lynn-Heritage State Park sign, 9.51 m (31.2 ft) west of the west end of the
sea wall, and level with the ground.
BENCH MARK STAMPING: 3187 E 1992
DESIGNATION: 844 3187 E
MONUMENTATION: Tidal Station disk VM#: 12091
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete fence base OPUS PID:
LATITUDE: 42° 27.5' N ( 42.45830) LONGITUDE: 70° 56.6' W ( -70.94330)
The bench mark is a disk set at the west end of the concrete base of an
east/west oriented iron fence which runs in the center of the median strip of
Lynnway, 31.58 m (103.6 ft) east of the west end of the median strip, 3.81 m
(12.5 ft) north of the north curb of the east bound traffic lane, 0.70 m (2.3
ft) west of the west end of the iron fence, and 0.12 m (0.4 ft) above the
ground.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 5
Station ID: 8443187 PUBLICATION DATE: 04/21/2003
Name: LYNN
MA
NOAA Chart: 13275 Latitude: 42° 27.5' N ( 42.45830)
USGS Quad: Lynn Longitude: 70° 56.6' W ( -70.94330)
T I D A L D A T U M S
Tidal datums at LYNN based on:
LENGTH OF SERIES: 3 Months
TIME PERIOD: July 1992 - September 1992
TIDAL EPOCH: 1983-2001
CONTROL TIDE STATION: 8443970 BOSTON, BOSTON HARBOR
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
HIGHEST OBSERVED WATER LEVEL (08/28/1992) =
MEAN HIGHER HIGH WATER MHHW = 3.030
MEAN HIGH WATER MHW = 2.895
MEAN SEA LEVEL MSL = 1.522
MEAN TIDE LEVEL MTL = 1.499
MEAN LOW WATER MLW = 0.103
MEAN LOWER LOW WATER MLLW = 0.000
LOWEST OBSERVED WATER LEVEL (07/31/1992) =
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
3187 A 1992 5.223 2.328
3187 B 1992 5.330 2.435
3187 C 1992 4.720 1.825
3187 D 1992 5.271 2.376
3187 E 1992 5.656 2.761
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 5
Station ID: 8443187 PUBLICATION DATE: 04/21/2003
Name: LYNN
MA
NOAA Chart: 13275 Latitude: 42° 27.5' N ( 42.45830)
USGS Quad: Lynn Longitude: 70° 56.6' W ( -70.94330)
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.