U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
Datums Page                                                        Page  1 of  7

                                                                                
Station ID: 9063079                         PUBLICATION DATE:  08/11/2017
Name:       MARBLEHEAD, LAKE ERIE                             
            OH
NOAA Chart: 14844                           Latitude:   41° 32.6' N (  41.54364)
USGS Quad:                                  Longitude:  82° 43.9' W ( -82.73139)


TO REACH THE NOS GAUGING STATION, IN MARBLEHEAD, OTTAWA COUNTY, OHIO, FROM THE
INTERSECTION OF ROUTE 163 (MAIN ST) AND FRANCES ST, PROCEED NORTH ON FRANCES ST
FOR APPROX 0.1 MILE (0.2 KM) TO THE INTERSECTION WITH PRARIE RD, THEN PROCEED
EAST ON PRARIE RD FOR APPROX 0.05 MILE (0.08KM) TO THE USCG GATE, THEN PROCEED
THRU GATE AND TRAVEL NORTH FOR APPROX 0.1 MILE (0.2 KM) ON PAVED DRIVE TO NORTH
END OF PROPERTY, ON THE PROPERTY OF THE U.S. COAST GUARD, NEAR THE BOAT HOIST
RAMP AND CONCRETE CAPPED CELLS, TO THE NOS GAUGING STATION.


                    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  7

                                                                                
Station ID: 9063079                         PUBLICATION DATE:  08/11/2017
Name:       MARBLEHEAD, LAKE ERIE                             
            OH
NOAA Chart: 14844                           Latitude:   41° 32.6' N (  41.54364)
USGS Quad:                                  Longitude:  82° 43.9' W ( -82.73139)


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


                 PRIMARY BENCH MARK STAMPING:  Z 317 1980
                         DESIGNATION:          Z 317

MONUMENTATION:           Flange-encased Rod                    VM#:        12827
AGENCY:                  National Geodetic Survey              IDB PID#:  MC0984
SETTING CLASSIFICATION:  Stainless steel rod w/o sleeve        OPUS PID:        
LATITUDE:   41° 32.6' N (  41.54292)          LONGITUDE:  82° 43.9' W ( -82.73183)


The bench mark is a stainless steel rod set in the grassy area at the NW end of
the parking lot on the W side of the Coast Guard building office, 56.3 ft (17.2
m) NW of the NW corner of the building, 28.2 ft (8.6 m) W of the center of the
paved road leading down to the boat house and lake, 6.55 m (21.49 ft) N of the
NW corner of the paved parking lot, 2.8 m (9.2 ft) Eof a N-S fence line between
USCG and ferry landing property.  Encased in a 5-inch PVC pipe with aluminum
access cover and concrete kick block with witness post, level with the ground.



                         BENCH MARK STAMPING:   
                         DESIGNATION:          906 3079 CELL

MONUMENTATION:           See descriptive text                  VM#:        12828
AGENCY:                                                        IDB PID#:  MC0990
SETTING CLASSIFICATION:  2 Chiseled lines on steel pile        OPUS PID:        
LATITUDE:   41° 32.6' N (  41.54361)          LONGITUDE:  82° 43.9' W ( -82.73139)


The bench mark is 2 chiseled lines set on the steel cell portion on the E side
of the break wall which forms the W side of the boat basin on the N side of the
boat house, 21.8 m (71.5 ft) N of the NW corner of the boat house, 7.1 m (23.3
ft) S of the cylindrical pipe for gauge well.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  3 of  7

                                                                                
Station ID: 9063079                         PUBLICATION DATE:  08/11/2017
Name:       MARBLEHEAD, LAKE ERIE                             
            OH
NOAA Chart: 14844                           Latitude:   41° 32.6' N (  41.54364)
USGS Quad:                                  Longitude:  82° 43.9' W ( -82.73139)


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


                         BENCH MARK STAMPING:  AMC MARBLEHEAD 1976
                         DESIGNATION:          MARBLEHEAD

MONUMENTATION:           Survey disk                           VM#:        12829
AGENCY:                  National Ocean Survey                 IDB PID#:  MC0991
SETTING CLASSIFICATION:  Breakwall                             OPUS PID:        
LATITUDE:   41° 32.6' N (  41.54389)          LONGITUDE:  82° 43.9' W ( -82.73150)


The bench mark is a disk set atop the W concrete break wall, 14.2 m (46.6 ft) NW
of the steel pipe for a water level gage well, 10.3 m (33.8 ft) S of the N end
of the break wall, and just N of a U.S Coast Guard sign, set in the surface of
the concrete break wall/cell.



                         BENCH MARK STAMPING:  3079 F 1982
                         DESIGNATION:          906 3079 F

MONUMENTATION:           Bench Mark disk                       VM#:        12831
AGENCY:                  National Ocean Survey                 IDB PID#:  AB6925
SETTING CLASSIFICATION:  Concrete ferry slip abutment          OPUS PID:        
LATITUDE:   41° 32.6' N (  41.54400)          LONGITUDE:  82° 43.9' W ( -82.73189)


The bench mark is a disk at the Kelly's Island Ferry Dock area, near the water's
edge, in SE corner of concrete ferry slip abutment of the most E of tow ferry
slips, 13.1 m (43.0 ft) NNW of NW corner post of covered passenger waiting area,
1.60 m (5.25 ft) NW of a power pole and 1.1 m S of the SE leg of steel ramp
support.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  4 of  7

                                                                                
Station ID: 9063079                         PUBLICATION DATE:  08/11/2017
Name:       MARBLEHEAD, LAKE ERIE                             
            OH
NOAA Chart: 14844                           Latitude:   41° 32.6' N (  41.54364)
USGS Quad:                                  Longitude:  82° 43.9' W ( -82.73139)


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


                         BENCH MARK STAMPING:  3079 G 1982
                         DESIGNATION:          906 3079 G

MONUMENTATION:           Bench Mark disk                       VM#:        12832
AGENCY:                  National Ocean Survey                 IDB PID#:  AB6926
SETTING CLASSIFICATION:  Concrete foundation                   OPUS PID:        
LATITUDE:   41° 32.6' N (  41.54314)          LONGITUDE:  82° 43.9' W ( -82.73114)


The bench mark is a disk on the U.S. Coast Guard base, in W side of concrete of
sliding door foundation of boathouse garage, 0.6 ft (18.3 cm) E of the most W
door jam, being the highest point of line in center of a standard NOS disc set
flush in the concrete.



                         BENCH MARK STAMPING:  3079 H 1988
                         DESIGNATION:          906 3079 H

MONUMENTATION:           Bench Mark disk                       VM#:        12833
AGENCY:                  National Ocean Survey                 IDB PID#:        
SETTING CLASSIFICATION:  Base of flag/weather vane tower       OPUS PID:        
LATITUDE:   41° 32.5' N (  41.54181)          LONGITUDE:  82° 43.9' W ( -82.73197)


The bench mark is a disk on the W side of Frances St, in James Park, in the base
of a flag and weather vane tower, 83.30 m (273.29 ft) S of the S side of Prarie
Road, 23.30 m (76.44 ft) W of the W edge of Frances St, 4.00 m (13.12 ft) SW of
the SW face of VFW American Legion monument, 2.20 m (7.22 ft) E of the W leg of
the tower, set flush with the concrete foundation base.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  5 of  7

                                                                                
Station ID: 9063079                         PUBLICATION DATE:  08/11/2017
Name:       MARBLEHEAD, LAKE ERIE                             
            OH
NOAA Chart: 14844                           Latitude:   41° 32.6' N (  41.54364)
USGS Quad:                                  Longitude:  82° 43.9' W ( -82.73139)


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


                         BENCH MARK STAMPING:  3079 J 1993
                         DESIGNATION:          906 3079 J

MONUMENTATION:           Bench Mark disk                       VM#:        12834
AGENCY:                  National Ocean Service (NOS)          IDB PID#:  AB6927
SETTING CLASSIFICATION:  Stainless steel rod w/o sleeve        OPUS PID:        
LATITUDE:   41° 32.7' N (  41.54461)          LONGITUDE:  82° 43.9' W ( -82.73133)


The bench mark is a disk on the U.S. Coast Guard station, 39.8 m (130.6 ft) SW
from the SE light pole along the basins SE side, 24.7 m (81.0 ft) SW of the SW
corner of the pyrotechnics shelter, 21.7 m (71.2 ft) NNE of the NE corner of a
concrete parking area on the N side of the Coast Guard facility building, 9.8 m
(32.2 ft) E of the NE corner of the fuel storage building with block foundation,
being a standard NOS disc crimped atop a 1/2-inch stainless steel rod 3.7 m
(12.1 ft) long driven to refusal with a 5 inch PVC pipe with aluminum NGS logo
cover and concrete kick pad flush with the ground, with witness post.



                         BENCH MARK STAMPING:  3079 L RESET 2007
                         DESIGNATION:          906 3079 L RESET 2007

MONUMENTATION:           Bench Mark disk                       VM#:        18482
AGENCY:                  National Ocean Service (NOS)          IDB PID#:        
SETTING CLASSIFICATION:  Concrete retaining wall               OPUS PID:        
LATITUDE:   41° 32.6' N (  41.54353)          LONGITUDE:  82° 43.9' W ( -82.73142)


The bench mark is a disk on the N end of the U.S. Coast Guard property, near the
water's edge, set flush in concrete retaining/headwall near the W side of the
boat basin, 15.66 m (51.38 ft) W of the E edge of headwall, 1.15 m (3.77 ft) S
of the N edge of headwall, 0.26 m (0.85 ft) E of the W edge of headwall, being
the highest point of a bronze survey disk set flush with the concrete.





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: 9063079                         PUBLICATION DATE:  08/11/2017
Name:       MARBLEHEAD, LAKE ERIE                             
            OH
NOAA Chart: 14844                           Latitude:   41° 32.6' N (  41.54364)
USGS Quad:                                  Longitude:  82° 43.9' W ( -82.73139)


                             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: 9063079                         PUBLICATION DATE:  08/11/2017
Name:       MARBLEHEAD, LAKE ERIE                             
            OH
NOAA Chart: 14844                           Latitude:   41° 32.6' N (  41.54364)
USGS Quad:                                  Longitude:  82° 43.9' W ( -82.73139)


                             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/.