U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
Datums Page                                                        Page  1 of  9

                                                                                
Station ID: 9014080                         PUBLICATION DATE:  08/11/2017
Name:       ST. CLAIR STATE POLICE, ST. CLAIR RIVER           
            MI
NOAA Chart: 14852                           Latitude:   42° 48.7' N (  42.81222)
USGS Quad:                                  Longitude:  82° 29.1' W ( -82.48556)


TO REACH THE NOS GAUGING STATION, IN ST CLAIR, ST CLAIR COUNTY, MICHIGAN, FROM
THE INTERSECTION OF CLINTON AVE AND M-29, PROCEED SOUTH ON M-29 FOR APPROX 0.55
MILE (0.89 KM) TO THE BM ON THE EAST SIDE OF M-29, BEHIND A RESIDENCE LOCATED AT
1419 RIVERSIDE DRIVE (STATE HIGHWAY 29), 0.5 MILE (0.8 KM) SOUTH OF THE STATE
HIGHWAY 29 DRAW BRIDGE OVER PINE RIVER,  THE GAUGE HOUSE IS LOCATED BEHIND THE
RESIDENCE.


                    G R E A T  L A K E S   B E N C H   M A R K S


                 PRIMARY BENCH MARK STAMPING:  A 237 1980
                         DESIGNATION:          A 237

MONUMENTATION:           Metal Rod                             VM#:        12983
AGENCY:                  National Geodetic Survey              IDB PID#:  NE0943
SETTING CLASSIFICATION:  Stainless steel rod in sleeve         OPUS PID:        
LATITUDE:   42° 48.8' N (  42.81258)          LONGITUDE:  82° 29.1' W ( -82.48556)


The primary bench mark is a stainless steel rod on the property of the 1417
Riverside Drive residence, 80 m (262.5 ft) E of the centerline of Highway 29,
34.2 m (112.2 ft) N of the NW corner of the gauge house, 34.1 m (111.9 ft) SSW
of the inside weld joint of the N corner of the steel bulkhead on the river side
of the property, 20.1 m (65.9 ft) ENE of NE corner of house 1419 Riverside
Drive, and 9.95 m (32.64 ft) W of the E face of steel bulkhead, set to a depth
of 9.7 m (31.8 ft) in a sleeve extending to a depth of 3.0 m (9.8 ft) encased in
a pipe flush with the ground. Mark is 1 m (3.3 ft) below ground, and has a NOAA
witness post.  Sleeve is a 6" PVC pipe with aluminum access lid and concrete
kick block.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  2 of  9

                                                                                
Station ID: 9014080                         PUBLICATION DATE:  08/11/2017
Name:       ST. CLAIR STATE POLICE, ST. CLAIR RIVER           
            MI
NOAA Chart: 14852                           Latitude:   42° 48.7' N (  42.81222)
USGS Quad:                                  Longitude:  82° 29.1' W ( -82.48556)


                    G R E A T  L A K E S   B E N C H   M A R K S


                         BENCH MARK STAMPING:  POLICE
                         DESIGNATION:          901 4080 POLICE

MONUMENTATION:           Survey disk                           VM#:        12984
AGENCY:                  National Geodetic Survey              IDB PID#:  NE0942
SETTING CLASSIFICATION:  Concrete foundation                   OPUS PID:        
LATITUDE:   42° 48.7' N (  42.81208)          LONGITUDE:  82° 29.1' W ( -82.48564)


The bench mark is a disk 80 m (262.5 ft) E of the center line of Highway 29, set
in the concrete foundation of the NOAA water level gauge house, 15.8 m (51.8 ft)
W of the E face of the steel bulkhead, 5.2 m (17.1 ft) ENE of utility pole
number 30 G 6, 2.5 m (8.2 ft) S of the NW corner of the gauge house, 0.14 m
(0.46 ft) W of the SW corner of the gauge house, being a standard disc 0.9 m
(3.0 ft) below the ground with 5" PVC sleeve with aluminum access cover flush
with the ground, stamped "Police".

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  3 of  9

                                                                                
Station ID: 9014080                         PUBLICATION DATE:  08/11/2017
Name:       ST. CLAIR STATE POLICE, ST. CLAIR RIVER           
            MI
NOAA Chart: 14852                           Latitude:   42° 48.7' N (  42.81222)
USGS Quad:                                  Longitude:  82° 29.1' W ( -82.48556)


                    G R E A T  L A K E S   B E N C H   M A R K S


                         BENCH MARK STAMPING:   
                         DESIGNATION:          901 4080 MSP

MONUMENTATION:           Metal Rod                             VM#:        12985
AGENCY:                  National Geodetic Survey              IDB PID#:  NE0015
SETTING CLASSIFICATION:  Copper-clad steel rod                 OPUS PID:        
LATITUDE:   42° 48.8' N (  42.81264)          LONGITUDE:  82° 29.2' W ( -82.48606)


The bench mark is a copper-clad steel rod 37.7 m (123.7 ft) SSE of the first of
3 large power poles running N and S along the E side of the highway, the first
being the most N power pole number S25CD811, 37.6 m (123.4 ft) NNE of the third
and most S of the poles numbered S25CD812, 21.2 m (69.6 ft) NNW of the NW corner
of house 1419 Riverside Drive, 14.7 m (48.2 ft) E of the center line of the
highway, 7.6 m (24.9 ft) E of the E edge of a drain culvert, 5.2 m (17.1 ft) ESE
of the face of the second power pole number DE8260BB of the three power poles,
being the highest pt on top of a 5/8-inch copper-coated steel rod, 6.1 m (20.0
ft) long. Mark is 0.6 m (2.0 ft) below ground. With a 5-inch PVC pipe and
aluminum access cover, surrounded of a mass of concrete flush with the ground,
stamped "MSP".

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  4 of  9

                                                                                
Station ID: 9014080                         PUBLICATION DATE:  08/11/2017
Name:       ST. CLAIR STATE POLICE, ST. CLAIR RIVER           
            MI
NOAA Chart: 14852                           Latitude:   42° 48.7' N (  42.81222)
USGS Quad:                                  Longitude:  82° 29.1' W ( -82.48556)


                    G R E A T  L A K E S   B E N C H   M A R K S


                         BENCH MARK STAMPING:  ANGLER
                         DESIGNATION:          901 4080 ANGLER

MONUMENTATION:           Survey disk                           VM#:        12986
AGENCY:                  National Geodetic Survey              IDB PID#:  NE0014
SETTING CLASSIFICATION:  Copper-clad steel rod                 OPUS PID:        
LATITUDE:   42° 48.8' N (  42.81256)          LONGITUDE:  82° 29.2' W ( -82.48683)


The bench mark is a disk set N of the NE corner of the Angler Rod company
building, 45.4 m (148.9 ft) W of the center line of highway 29, 29.1 m (95.5 ft)
SE of power pole number 634 with a transformer, 2.4 m (7.9 ft) N of the NE
corner of the building, and 0.70 m (2.30 ft) W of the W edge of the sidewalk
leading to the front of the building, being highest point on top of a 5/8-inch
diameter copper-coated steel rod, 4.9 m (16.1 ft) long, encased in a 5-inch PVC
pipe with an aluminum access cover.  Mark is 6 inches below ground, access cover
is flush with ground.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  5 of  9

                                                                                
Station ID: 9014080                         PUBLICATION DATE:  08/11/2017
Name:       ST. CLAIR STATE POLICE, ST. CLAIR RIVER           
            MI
NOAA Chart: 14852                           Latitude:   42° 48.7' N (  42.81222)
USGS Quad:                                  Longitude:  82° 29.1' W ( -82.48556)


                    G R E A T  L A K E S   B E N C H   M A R K S


                         BENCH MARK STAMPING:  4080 F 1993
                         DESIGNATION:          901 4080 F

MONUMENTATION:           Bench Mark disk                       VM#:        12987
AGENCY:                  National Ocean Service (NOS)          IDB PID#:  AC9129
SETTING CLASSIFICATION:  Stainless steel rod w/o sleeve        OPUS PID:        
LATITUDE:   42° 49.0' N (  42.81594)          LONGITUDE:  82° 29.2' W ( -82.48594)


The bench mark is a disk on the property of the Akzo Salt Company, NNE of the
intersection of Riverside Drive and Laure Street, 9.05 m (29.69 ft) ESE of the
center lane of Laure Street, 21.1 m (69.2 ft) SE of power pole number 74, 17.7 m
(58.1 ft) WSW of the SE corner of aluminum storage shed belonging to Akzo Salt
Company, 0.95 m (3.12 ft) SSW of the SW corner of aluminum storage shed, being
highest point on top of bronze disc crimped atop a 5/8-inch diameter stainless
steel rod driven 4.9 m (16.1 ft) to refusal, and encased in a 5-inch PVC pipe
with aluminum access cover.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  6 of  9

                                                                                
Station ID: 9014080                         PUBLICATION DATE:  08/11/2017
Name:       ST. CLAIR STATE POLICE, ST. CLAIR RIVER           
            MI
NOAA Chart: 14852                           Latitude:   42° 48.7' N (  42.81222)
USGS Quad:                                  Longitude:  82° 29.1' W ( -82.48556)


                    G R E A T  L A K E S   B E N C H   M A R K S


                         BENCH MARK STAMPING:  RCH C-32A 1939
                         DESIGNATION:          901 4080 C 32 A

MONUMENTATION:           Survey disk                           VM#:        12988
AGENCY:                  US Lake Survey                        IDB PID#:  NE0018
SETTING CLASSIFICATION:  Concrete foundation                   OPUS PID:        
LATITUDE:   42° 49.0' N (  42.81628)          LONGITUDE:  82° 29.2' W ( -82.48678)


The bench mark is a disk set vertically 0.9 m (3.0 ft) above the ground in the S
face of the concrete foundation of the Akzo Salt Company building at 1213
Riverside Avenue (State Highway 29) , a gray single story building at the NE
corner of the intersection of Laure Street and State Highway 29, 30.5 m (100.1
ft) E of the center line of the highway, 15.2 m (49.9 ft) E of the SW corner of
the building, 5.64 m (18.50 ft) W of a electric meter on the S face of the
building, 8.0 m (26.2 ft) N of the center line of gravel road on S side of
building.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  7 of  9

                                                                                
Station ID: 9014080                         PUBLICATION DATE:  08/11/2017
Name:       ST. CLAIR STATE POLICE, ST. CLAIR RIVER           
            MI
NOAA Chart: 14852                           Latitude:   42° 48.7' N (  42.81222)
USGS Quad:                                  Longitude:  82° 29.1' W ( -82.48556)


                    G R E A T  L A K E S   B E N C H   M A R K S


                         BENCH MARK STAMPING:   
                         DESIGNATION:          IBM 43 IBC

MONUMENTATION:           Survey disk                           VM#:        12989
AGENCY:                                                        IDB PID#:  NE0012
SETTING CLASSIFICATION:                                        OPUS PID:        
LATITUDE:   42° 48.5' N (  42.80856)          LONGITUDE:  82° 29.2' W ( -82.48592)


The bench mark is a disk at residence 1613 Riverside Road, between 2 homes,
11.30 m (37.07 ft) W of the W edge of the steel bulkhead (breakwater) at the
river's edge, 8.70 m (28.54 ft) E of the NE corner of house 1617, 5.90 mm (19.36
ft) SW of house 1613, projecting approx 0.60 meters (1.97 ft) above the ground,
being highest point on top of copper bolt set into top of a concrete monument,
forming international boundary monument no. 43.





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  8 of  9

                                                                                
Station ID: 9014080                         PUBLICATION DATE:  08/11/2017
Name:       ST. CLAIR STATE POLICE, ST. CLAIR RIVER           
            MI
NOAA Chart: 14852                           Latitude:   42° 48.7' N (  42.81222)
USGS Quad:                                  Longitude:  82° 29.1' W ( -82.48556)


                             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  9 of  9

                                                                                
Station ID: 9014080                         PUBLICATION DATE:  08/11/2017
Name:       ST. CLAIR STATE POLICE, ST. CLAIR RIVER           
            MI
NOAA Chart: 14852                           Latitude:   42° 48.7' N (  42.81222)
USGS Quad:                                  Longitude:  82° 29.1' W ( -82.48556)


                             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/.