U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 7
Station ID: 9099090 PUBLICATION DATE: 08/11/2017
Name: GRAND MARAIS, LAKE SUPERIOR
MN
NOAA Chart: 14967 Latitude: 47° 44.9' N ( 47.74856)
USGS Quad: Longitude: 90° 20.5' W ( -90.34128)
TO REACH THE NOS GAUGING STATION, IN COOK COUNTY, GRAND MARAIS, MINNESOTA, FROM
THE INTERSECTION OF HWY 61 AND 8TH AVE, PROCEED EAST ON HWY 61 FOR APPROX 0.10
MILE, THE ETG IS ON THE SOUTH SIDE OF HWY 61, IN THE MUNICIPAL CAMPGROUND (114
SOUTH 8TH AVENUE WEST), MUNICIPAL CAMPGROUND ENTRANCE IS LOCATED ON THE EAST
SIDE OF 8TH AVE, AT THE NE CORNER OF THE PROPERTY.
G R E A T L A K E S B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 909 9090 SCOTT
DESIGNATION: 909 9090 SCOTT
MONUMENTATION: Metal Rod VM#: 13395
AGENCY: National Geodetic Survey IDB PID#: SH0674
SETTING CLASSIFICATION: Metal rod driven into the ground OPUS PID:
LATITUDE: 47° 44.9' N ( 47.74908) LONGITUDE: 90° 20.4' W ( -90.33989)
The bench mark is a metal rod driven into the ground on the E side of the
Dockside Fish Market, against the wall under the stairs, 22.9 meters (75.1 ft) S
of the centerline of the highway, 21.9 meters (71.9 ft) N of the NW corner of a
green boathouse, 21.10 meters (69.23 ft) NW of a power line pole, no. 139, with
guy wire, 17.15 meters (56.27 ft) E of the extended centerline of the avenue,
7.12 meters (23.36 ft) S of the NE corner of the Dockside Fish Market, with a
5-inch PVC pipe and aluminum access cover stamped "909 9090 Scott" surrounded by
concrete and flush with the ground.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 7
Station ID: 9099090 PUBLICATION DATE: 08/11/2017
Name: GRAND MARAIS, LAKE SUPERIOR
MN
NOAA Chart: 14967 Latitude: 47° 44.9' N ( 47.74856)
USGS Quad: Longitude: 90° 20.5' W ( -90.34128)
G R E A T L A K E S B E N C H M A R K S
BENCH MARK STAMPING: ECKEL 1966
DESIGNATION: 909 9090 ECKEL
MONUMENTATION: Survey disk VM#: 13396
AGENCY: Army Corps of Engineers IDB PID#: SH0671
SETTING CLASSIFICATION: Foundation OPUS PID:
LATITUDE: 47° 44.9' N ( 47.74856) LONGITUDE: 90° 20.5' W ( -90.34128)
The bench mark is a disk at the NW corner of the NOS water level gauge house
foundation, 11.3 meters (37.1 ft) SW of the SW corner of the N house folk
school, 2.35 meters (7.71 ft) NW of the SW corner of the gauge house, 2.15
meters (7.05 ft) NE of the NE corner of the gauge house.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 7
Station ID: 9099090 PUBLICATION DATE: 08/11/2017
Name: GRAND MARAIS, LAKE SUPERIOR
MN
NOAA Chart: 14967 Latitude: 47° 44.9' N ( 47.74856)
USGS Quad: Longitude: 90° 20.5' W ( -90.34128)
G R E A T L A K E S B E N C H M A R K S
BENCH MARK STAMPING: Z 176 1935
DESIGNATION: Z 176
MONUMENTATION: Bench Mark disk VM#: 13397
AGENCY: US Coast and Geodetic Survey IDB PID#: SH0005
SETTING CLASSIFICATION: Top of concrete monument OPUS PID:
LATITUDE: 47° 45.0' N ( 47.74919) LONGITUDE: 90° 20.5' W ( -90.34083)
The bench mark is a disk at the hwy edge of the N house folk school property,
15.65 meters (51.35 ft) W of the edge of a paved entrance way to the folk
school, 14.0 meters (45.9 ft) S of the centerline of the highway, and almost
directly under a spruce tree, 6.70 meters (21.98 ft) S of the S edge of Highway
61, 3.05 meters (10.01 ft) N of the edge of a paved parking area of the folk
school, 1.05 meters (3.44 ft) SW of the SW face of a spruce tree.
BENCH MARK STAMPING:
DESIGNATION: 909 9090 LONG
MONUMENTATION: Metal Rod VM#: 13399
AGENCY: IDB PID#: SH0676
SETTING CLASSIFICATION: Metal rod driven into the ground OPUS PID:
LATITUDE: 47° 44.8' N ( 47.74603) LONGITUDE: 90° 20.0' W ( -90.33283)
The bench mark is a metal rod 11.7 meters (38.4 ft) NE of the SE corner of the
Coast Guard Station, 11.6 meters (38.1 ft) W of the SE leg of a flag tower, 2.2
meters (7.2 ft) NW of the NW corner pump house, 0.8 meters (2.6 ft) S of and in
line with the W wall of a garage, 7.62 cm (.25 feet) below ground surface with a
5-inch PVC pipe and aluminum access cover stamped "909 9090 Long" surrounded by
a concrete kick block flush with the ground.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 7
Station ID: 9099090 PUBLICATION DATE: 08/11/2017
Name: GRAND MARAIS, LAKE SUPERIOR
MN
NOAA Chart: 14967 Latitude: 47° 44.9' N ( 47.74856)
USGS Quad: Longitude: 90° 20.5' W ( -90.34128)
G R E A T L A K E S B E N C H M A R K S
BENCH MARK STAMPING:
DESIGNATION: 909 9090 GUN
MONUMENTATION: Metal Rod VM#: 13401
AGENCY: IDB PID#: SH0673
SETTING CLASSIFICATION: Metal rod driven into the ground OPUS PID:
LATITUDE: 47° 44.9' N ( 47.74881) LONGITUDE: 90° 20.4' W ( -90.34044)
The bench mark is a metal rod driven into the ground at the SE corner of the
most northern N House folk school wood shop, across from U.S Highway 61, 20.60
meters (67.59 ft) N of the N house folk school dock, 12.73 meters (41.77 ft) S
of the NE corner of the folk school, 10.07 meters (33.04 ft) E of the SW corner
of the N House folk school wood shop, 21.3 cm S of and in line with the E face
of the warehouse. 0.60 feet (18.29 cm) off E face of foundation, approx 0.65
feet (19.81 cm) below rocky shale ground surface, protected by PVC sleeve with
alum access lid and witness post.
BENCH MARK STAMPING: 909 9090 E
DESIGNATION: 909 9090 E
MONUMENTATION: Bench Mark disk VM#: 17273
AGENCY: National Ocean Service IDB PID#: DM4064
SETTING CLASSIFICATION: Stainless steel rod w/o sleeve OPUS PID:
LATITUDE: 47° 44.9' N ( 47.74817) LONGITUDE: 90° 20.0' W ( -90.33358)
The bench mark is a brass disk crimpted to a stainless steel rod driven 7.3 m
(24.0 ft) to refusal in the picnic area just N of the Coast Guard station, 40.0
m (131.2 ft) NNE of the third most N light pole in the picnic area, 34.6 m
(113.5 ft) E of the N end of the steel sheet pile bulkhead, 29.2 m (95.8 ft) S
of the SW corner of the brown sided residence at 17 Broadway Avenue, 25.5 m
(83.7 ft) NE of the second most N light pole in the picnic area encased in a 5"
PVC pipe with concrete kick block and an aluminum access cover.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 7
Station ID: 9099090 PUBLICATION DATE: 08/11/2017
Name: GRAND MARAIS, LAKE SUPERIOR
MN
NOAA Chart: 14967 Latitude: 47° 44.9' N ( 47.74856)
USGS Quad: Longitude: 90° 20.5' W ( -90.34128)
G R E A T L A K E S B E N C H M A R K S
BENCH MARK STAMPING: MARAIS 1982 NOS 1992
DESIGNATION: MARAIS RESET
MONUMENTATION: Bench Mark disk VM#: 17274
AGENCY: National Geodetic Survey IDB PID#: AA2869
SETTING CLASSIFICATION: Rock outcrop OPUS PID:
LATITUDE: 47° 44.7' N ( 47.74517) LONGITUDE: 90° 20.1' W ( -90.33464)
The bench mark is a disk 23.0 meters (75.5 ft) past a small group of spruce
trees and the station on the highest part of the rock, 6.60 meters (21.65 ft) W
of the centerline of the face of a 4.3 m (14.2 ft) by 2.50 m (8.20 ft) concrete
pad, 4.36 meters (14.30 ft) NW of a 0.9 m (2.9 ft) by 1.0 m (3.2 ft) concrete
footing, 3.60 meters (11.81 ft) S of the approximant center of a concrete
footing which is the center of three footings set in a drill hole in the
bedrock.
BENCH MARK STAMPING:
DESIGNATION: 909 9090 F
MONUMENTATION: Chiseled Square VM#: 19345
AGENCY: National Ocean Service IDB PID#:
SETTING CLASSIFICATION: Concrete cap OPUS PID:
LATITUDE: 47° 45.0' N ( 47.74931) LONGITUDE: 90° 20.3' W ( -90.33781)
the BM is a chiseled square on the south side of HWY 61 on the corner of
concrete cap near water's edge, 21.0 m (68.9 ft) S of the centerline of main
road (SR-61), 5.44 m (17.8 ft) W of the W face of stone 'Geology of Minnesota'
plaque of monument, 1.12 m (3.7 ft) S of S face of a stone wall, 0.36 m (1.2 ft)
above the bulkhead.
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 6 of 7
Station ID: 9099090 PUBLICATION DATE: 08/11/2017
Name: GRAND MARAIS, LAKE SUPERIOR
MN
NOAA Chart: 14967 Latitude: 47° 44.9' N ( 47.74856)
USGS Quad: Longitude: 90° 20.5' W ( -90.34128)
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 7 of 7
Station ID: 9099090 PUBLICATION DATE: 08/11/2017
Name: GRAND MARAIS, LAKE SUPERIOR
MN
NOAA Chart: 14967 Latitude: 47° 44.9' N ( 47.74856)
USGS Quad: Longitude: 90° 20.5' W ( -90.34128)
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/.