U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 6
Station ID: 9075080 PUBLICATION DATE: 08/11/2017
Name: MACKINAW CITY, STRAITS OF MACKINAC
MI
NOAA Chart: 14881 Latitude: 45° 46.7' N ( 45.77789)
USGS Quad: Longitude: 84° 43.5' W ( -84.72533)
TO REACH THE NOS GAUGE HOUSE, IN MACKINAW CITY, CHEBOYGAN COUNTY, MICHIGAN, FROM
THE INTERSECTION OF HURON AVE AND RAILROAD AVE, PROCEED EAST ON RAILROAD AVE FOR
APPROX 0.48 KM (0.30 MI) TO THE ARNOLD FERRY DOCK LANDING,THE NOS WATER LEVEL
GAUGE HOUSE IS LOCATED AT THE FORMER STATE FERRY DOCK.
G R E A T L A K E S B E N C H M A R K S
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 6
Station ID: 9075080 PUBLICATION DATE: 08/11/2017
Name: MACKINAW CITY, STRAITS OF MACKINAC
MI
NOAA Chart: 14881 Latitude: 45° 46.7' N ( 45.77789)
USGS Quad: Longitude: 84° 43.5' W ( -84.72533)
G R E A T L A K E S B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: J 299 1983
DESIGNATION: J 299
MONUMENTATION: Flange-encased Rod VM#: 13068
AGENCY: National Geodetic Survey IDB PID#: QK0428
SETTING CLASSIFICATION: Stainless steel rod in sleeve OPUS PID:
LATITUDE: 45° 46.7' N ( 45.77808) LONGITUDE: 84° 43.6' W ( -84.72658)
The bench mark is a stainless steel rod 17.98 m (58.99 ft) West of the
centerline of Huron Avenue, 12.19 m (39.99 ft) North of the center of Railroad
Avenue, 5.1m (16.5 ft) SE of the SE corner of the Mackinaw Island Fudge Company,
4.02 m (13.19 ft) South of the South edges of an East-West sidewalk, 3.10m
(10.17 ft) East of the East edge of a North-South sidewalk, 3.1m (10.2 ft) East
of the East edge of a North-South sidewalk, 1.52m (4.99 ft) East of the North
metal post supporting a sign (line up for the ferry) , protected by PVC sleeve,
alum access lid and witness post.
BENCH MARK STAMPING:
DESIGNATION: 907 5080 STATE DOCK
MONUMENTATION: Not specified (see descriptive text) VM#: 13069
AGENCY: US Lakes Survey IDB PID#: QK0258
SETTING CLASSIFICATION: Railroad rail OPUS PID:
LATITUDE: 45° 46.7' N ( 45.77783) LONGITUDE: 84° 43.2' W ( -84.72008)
The bench mark is on North side of the former state ferry dock, 37.49m (123.00
ft) West of gauge house, 3.35m (10.99 ft) South of the inside edge of concrete
wall along North side of dock, 0.45m (1.48 ft) South of the North curb of road,
0.3 m (1.0 ft) below the pavement, encased in a 6-inch diameter iron pipe with a
9-inch diameter metal cover, being highest point on top of end of a railroad
rail (highest point being on south side of head of the rail).
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 6
Station ID: 9075080 PUBLICATION DATE: 08/11/2017
Name: MACKINAW CITY, STRAITS OF MACKINAC
MI
NOAA Chart: 14881 Latitude: 45° 46.7' N ( 45.77789)
USGS Quad: Longitude: 84° 43.5' W ( -84.72533)
G R E A T L A K E S B E N C H M A R K S
BENCH MARK STAMPING: 5080 G 1991
DESIGNATION: 907 5080 G
MONUMENTATION: Bench Mark disk VM#: 13071
AGENCY: National Ocean Service (NOS) IDB PID#: AC6039
SETTING CLASSIFICATION: Bulkhead Retaining Wall (Cap) OPUS PID:
LATITUDE: 45° 46.6' N ( 45.77731) LONGITUDE: 84° 43.3' W ( -84.72094)
The bench mark is a disk on the state dock and fishing pier, 30.0m (98.4 ft) NW
of SE corner of seawall of state dock, 5.0m (16.4 ft) East of the West end of
the concrete retaining wall, 0.5m (1.6 ft) SW of the NE face of the concrete
seawall at the in-shore end of city fishing pier, set horizontally in concrete
seawall, 0.4m (1.3 ft) above ground level.
BENCH MARK STAMPING: 5080 H 1993
DESIGNATION: 907 5080 H
MONUMENTATION: Bench Mark disk VM#: 13072
AGENCY: National Ocean Service (NOS) IDB PID#: AC6040
SETTING CLASSIFICATION: Cap of Pier OPUS PID:
LATITUDE: 45° 46.6' N ( 45.77714) LONGITUDE: 84° 43.2' W ( -84.72050)
The bench mark is a disk on the state dock and city fishing pier, on South side
of city fishing pier, 5.49m (18.01 ft) SW of North most of two small bollards on
pier deck, 4.14m (13.58 ft) South of utility pole, 2.19m (7.19 ft) WNW of pier
safety ladder from deck of pier to water surface, set flush with deck surface.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 6
Station ID: 9075080 PUBLICATION DATE: 08/11/2017
Name: MACKINAW CITY, STRAITS OF MACKINAC
MI
NOAA Chart: 14881 Latitude: 45° 46.7' N ( 45.77789)
USGS Quad: Longitude: 84° 43.5' W ( -84.72533)
G R E A T L A K E S B E N C H M A R K S
BENCH MARK STAMPING: MACKINAW CITY 2008
DESIGNATION: 9075080 MACKINAW CITY
MONUMENTATION: Bench Mark disk VM#: 18967
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Gauge House Foundation OPUS PID:
LATITUDE: 45° 46.6' N ( 45.77744) LONGITUDE: 84° 43.3' W ( -84.72100)
The bench mark is a disk 1.78 m (5.84 ft) NE of the SW corner of concrete
foundation of gauge house, 1.07m (3.51 ft) NW of the West face of white NOS
gauge house wall, 0.8m (2.6 ft) SW of the North corner of concrete foundation of
gauge house, being a brass disc set in the gauge house foundation.
Foot Notes:
Above marks are published for informational purposes only. Long term stability
has not been reviewed prior to publication.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 6
Station ID: 9075080 PUBLICATION DATE: 08/11/2017
Name: MACKINAW CITY, STRAITS OF MACKINAC
MI
NOAA Chart: 14881 Latitude: 45° 46.7' N ( 45.77789)
USGS Quad: Longitude: 84° 43.5' W ( -84.72533)
D E F I N I T I O N S
The International Great Lakes Datum (IGLD) is the vertical height reference
datum used in the Great Lakes/St. Lawrence River System for engineering,
charting, channel dredging, navigation safety, power generation, and water
resource management. It is a coordinated datum between the United States and
Canada that ensures both countries are using the same reference for projects
in the Great Lakes basin. The datum origin, or zero, is defined as Mean Sea
Level at Pointe-au-Pere /Rimouski, Quebec, Canada at the mouth of the
St. Lawrence River. IGLD requires updating approximately every 25-30 years
to account for varying changes in the land surface elevations following the
retreat of the glaciers during the last ice age, referred to as Glacial
Isostatic Adjustment (GIA). The current IGLD 1985 was implemented in 1992.
IGLD 1985 uses dynamic heights as the vertical reference standard and lakes
station water level elevations are adjusted to provide a level geopotential
plane for lake level reference.
Dynamic height is the potential difference along the plumbline between the
vertical datum and a point of interest divided by a constant value of
gravity. In Canada and USA, the constant value of gravity is the
"normal gravity" on the ellipsoid at latitude 45° (9.806199 ms-2). Dynamic
heights have no geometric meaning. They are mainly used for the management
of water in large lakes, rivers and channels. The surface of a lake has a
constant dynamic height if undisturbed by currents, winds, atmospheric
pressure, etc.
The Hydraulic Corrector (HC) is the difference in the long term water level
mean between Subordinate and Master station. The difference (HC) is
subtracted algebraically at the subordinate gauge referencing the same
elevation as the master station. Thus all water levels on a given lake can
be referenced to the same lakes LWD/Chart Datum reference elevation.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 6 of 6
Station ID: 9075080 PUBLICATION DATE: 08/11/2017
Name: MACKINAW CITY, STRAITS OF MACKINAC
MI
NOAA Chart: 14881 Latitude: 45° 46.7' N ( 45.77789)
USGS Quad: Longitude: 84° 43.5' W ( -84.72533)
D E F I N I T I O N S
A Master Stations is the control point for determining water level
elevations on a particular lake of the Great Lakes. Since water surfaces
of the Great Lakes are considered to be at geopotential equal, all Mean
Water Level (MWL) values for stations on a particular lake should have the
same dynamic height. Therefore, all subordinate water level station MWL
values are adjusted to match the dynamic water level elevation of the Master
Station through the use of a hydraulic corrector. In the establishment of
International Great Lakes Datum (1985) the connecting waterways station
dynamic elevations were calculated through the use of a linear regression
while constraining the end points of the regression with the dynamic
elevations of the corresponding master station above and below the
connecting channel.
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 toNAVD88 are available from NGS through the World Wide
Web at National Geodetic Survey.
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/.