U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 7
Station ID: 9076033 PUBLICATION DATE: 08/11/2017
Name: LITTLE RAPIDS, ST. MARYS RIVER
MI
NOAA Chart: 14883 Latitude: 46° 29.1' N ( 46.48583)
USGS Quad: SAULT STE MARIE SOUTH Longitude: 84° 18.1' W ( -84.30167)
TO REACH THE NOS GAUGE STATION IN SAULT STE MARIE, CHIPPEWA COUNTY, MICHIGAN,
FROM THE INTERSECTION OF ASHMUN STREET AND PORTAGE AVE, PROCEED SOUTH ON PORTAGE
AVE FOR 3.7 KM (2.30 MI) TO ROTARY COMMUNITY PARK AND SUGAR ISLAND FERRY
LANDING, ON THE NORTH SIDE OF PORTAGE AVE, THE NOS GAUGE HOUSE IS ALONG THE
WATERS EDGE, IN THE ROTARY COMMUNITY PARK.
G R E A T L A K E S B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: D 293 1983
DESIGNATION: D 293
MONUMENTATION: Metal Rod VM#: 19355
AGENCY: National Geodetic Survey IDB PID#: RJ0616
SETTING CLASSIFICATION: Stainless steel rod in sleeve OPUS PID:
LATITUDE: 46° 29.2' N ( 46.48672) LONGITUDE: 84° 18.1' W ( -84.30244)
The bench mark is a stainless steel rod near the site of the Sugar Island ferry
landing, 27.28 meters (89.50 ft) NNW of a flagpole, 19.15 meters (62.83 ft) NNE
of the NE corner of the building, 8.35 m (27.39 ft) SSW of the NE corner of the
chain link fence, 5.80 m (19.03 ft) NNW of the NW corner of the SW concrete
foundation for the tower, 2.44 m (8.01 ft) SSE of the N chain link fence, 2.0 m
(6.6 ft) WSW of the NW corner of the NW concrete foundation for the tower, 0.15
m (0.49 ft) below ground surface, mark protected by PVC sleeve, aluminum access
lid and witness post.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 7
Station ID: 9076033 PUBLICATION DATE: 08/11/2017
Name: LITTLE RAPIDS, ST. MARYS RIVER
MI
NOAA Chart: 14883 Latitude: 46° 29.1' N ( 46.48583)
USGS Quad: SAULT STE MARIE SOUTH Longitude: 84° 18.1' W ( -84.30167)
G R E A T L A K E S B E N C H M A R K S
BENCH MARK STAMPING: FERRY DOCK 1981
DESIGNATION: 907 6032 FERRY DOCK
MONUMENTATION: Survey disk VM#: 19356
AGENCY: National Ocean Survey IDB PID#: RJ0617
SETTING CLASSIFICATION: CONCRETE CAISSON OPUS PID:
LATITUDE: 46° 29.1' N ( 46.48564) LONGITUDE: 84° 18.1' W ( -84.30144)
The bench mark is a survey disk 13.31 m (43.67 ft) SE of the SE edge of a
concrete boat landing ramp, 2.98 m (9.78 ft) N of the S edge of the S most
caisson, 2.56 m (8.40 ft) W of the E edge of the S most caisson , 0.30 m (0.98
ft) E of the E face of the S most mooring post, being a surface mark set into
the top of the concrete surface.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 7
Station ID: 9076033 PUBLICATION DATE: 08/11/2017
Name: LITTLE RAPIDS, ST. MARYS RIVER
MI
NOAA Chart: 14883 Latitude: 46° 29.1' N ( 46.48583)
USGS Quad: SAULT STE MARIE SOUTH Longitude: 84° 18.1' W ( -84.30167)
G R E A T L A K E S B E N C H M A R K S
BENCH MARK STAMPING: Z 295 1983
DESIGNATION: Z 295
MONUMENTATION: Metal Rod VM#: 19357
AGENCY: National Geodetic Survey IDB PID#: RJ0618
SETTING CLASSIFICATION: Stainless steel rod w/o sleeve OPUS PID:
LATITUDE: 46° 29.1' N ( 46.48486) LONGITUDE: 84° 18.1' W ( -84.30108)
The bench mark is a metal rod 23.5 m (77.1 ft) NW of the NW corner of the men's
restroom, 9.34 m (30.64 ft) SW of the centerline of the driveway, 2.38 m (7.8
ft) SW of the NE post for the Rotary Park sign, and 1m (3.3 ft) in front of the
Rotary Park sign, mark is protected by PVC sleeve, alum access lid and witness
post.
BENCH MARK STAMPING:
DESIGNATION: 907 6032 LITTLE RAPIDS
MONUMENTATION: Metal Rod VM#: 19358
AGENCY: IDB PID#: RJ0123
SETTING CLASSIFICATION: Rock outcrop OPUS PID:
LATITUDE: 46° 29.2' N ( 46.48661) LONGITUDE: 84° 18.1' W ( -84.30242)
The bench mark is a metal rod 122 m (400.3 ft) NE of the centerline of portage
street, near Coast Guard light pole no. 99, inside a security fenced area and on
U.S. Coast Guard property, 12.4 m (40.7 ft) N of the W corner of light keepers
house, 7.9 m (25.9 ft) NW of N corner of light keepers house, 7.36 m (24.15 ft)
S of SW leg of metal tower, 0.93 m (3.05 ft) W of witness post on fence line,
high point on top of a 1 1/4 inch iron rod embedded in top of a 2 x 2 foot (0.6
m) red sandstone boulder flush with the ground level.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 7
Station ID: 9076033 PUBLICATION DATE: 08/11/2017
Name: LITTLE RAPIDS, ST. MARYS RIVER
MI
NOAA Chart: 14883 Latitude: 46° 29.1' N ( 46.48583)
USGS Quad: SAULT STE MARIE SOUTH Longitude: 84° 18.1' W ( -84.30167)
G R E A T L A K E S B E N C H M A R K S
BENCH MARK STAMPING:
DESIGNATION: 907 6032 OUT
MONUMENTATION: Chiseled Square VM#: 19360
AGENCY: IDB PID#: RJ0126
SETTING CLASSIFICATION: CONCRETE SLAB OPUS PID:
LATITUDE: 46° 29.1' N ( 46.48458) LONGITUDE: 84° 18.1' W ( -84.30092)
The bench mark is a chiseled square on the N side of Portage Ave, 274.0 meters
(898.9 ft) SE of the Sugar Island ferry dock, 16.8 m (55.1 ft) W of the water's
edge, 3.25 m (10.66 ft) W of the centerline of the road, 0.12 m (0.39 ft) above
ground in the top of the N corner of a 3' x 3' ft concrete slab attached to the
women's restroom building between the men's and women's restrooms.
BENCH MARK STAMPING: 6032 F 2004
DESIGNATION: 906 6032 F
MONUMENTATION: Bench Mark disk VM#: 19362
AGENCY: National Ocean Service IDB PID#:
SETTING CLASSIFICATION: Concrete slab OPUS PID:
LATITUDE: 46° 29.1' N ( 46.48464) LONGITUDE: 84° 18.0' W ( -84.30078)
The bench mark is a disk 9.9 m (32.5 ft) E of the centerline of the asphalt
paved road, 2.01 m (6.6 ft) NE of a wooden light pole, 1.16 m (3.8 ft) SW of the
SW corner of a 6x4 ft (1.8 m) concrete slab and .09 m (0.3 ft) below surface of
ground.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 7
Station ID: 9076033 PUBLICATION DATE: 08/11/2017
Name: LITTLE RAPIDS, ST. MARYS RIVER
MI
NOAA Chart: 14883 Latitude: 46° 29.1' N ( 46.48583)
USGS Quad: SAULT STE MARIE SOUTH Longitude: 84° 18.1' W ( -84.30167)
G R E A T L A K E S B E N C H M A R K S
BENCH MARK STAMPING: LITTLE RAPIDS 2 2008
DESIGNATION: LITTLE RAPIDS 2
MONUMENTATION: Bench Mark disk VM#: 19363
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete footing OPUS PID:
LATITUDE: 46° 29.1' N ( 46.48583) LONGITUDE: 84° 18.1' W ( -84.30172)
The bench mark is a disk 32.97 m (108.17 ft) SE of SE corner of a 2.5 m (8.2 ft)
x 2.0 m (6.6 ft) cinderblock building on SE side of ferry loading ramp, 29.70 m
(97.44 ft) NNW of SE bollard on sheet pile wall, 8.37 m (27.46 ft) NE of the NE
edge of asphalt parking lot, 1.15 m (3.77 ft) WSW of SW face of gauge house,
0.11 m (0.36 ft) above ground.
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: 9076033 PUBLICATION DATE: 08/11/2017
Name: LITTLE RAPIDS, ST. MARYS RIVER
MI
NOAA Chart: 14883 Latitude: 46° 29.1' N ( 46.48583)
USGS Quad: SAULT STE MARIE SOUTH Longitude: 84° 18.1' W ( -84.30167)
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: 9076033 PUBLICATION DATE: 08/11/2017
Name: LITTLE RAPIDS, ST. MARYS RIVER
MI
NOAA Chart: 14883 Latitude: 46° 29.1' N ( 46.48583)
USGS Quad: SAULT STE MARIE SOUTH Longitude: 84° 18.1' W ( -84.30167)
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/.