U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
Datums Page                                                        Page  1 of  5

                                                                                
Station ID: 9063009                         PUBLICATION DATE:  08/11/2017
Name:       AMERICAN FALLS, NIAGARA FALLS, NIAGARA R          
            NY
NOAA Chart: 14822                           Latitude:   43°  4.9' N (  43.08106)
USGS Quad:                                  Longitude:  79°  3.7' W ( -79.06136)


TO REACH THE NOS GAUGING STATION AT AMERICAN FALLS, NIAGARA FALLS, NY, FROM THE
INTERSECTION OF 190 AND ROBERT MOSES PARKWAY, PROCEED WEST ON ROBERT MOSES
PARKWAY FOR 6.3 KM (3.90 MI) AND THE GAUGE HOUSE IS ON THE SOUTH SIDE OF ROBERT
MOSES PARKWAY.


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


                 PRIMARY BENCH MARK STAMPING:  3009 F 1990
                         DESIGNATION:          906 3009 F

MONUMENTATION:           Tidal Station disk                    VM#:        12766
AGENCY:                  National Ocean Service (NOS)          IDB PID#:  AC6011
SETTING CLASSIFICATION:  Stainless steel rod                   OPUS PID:        
LATITUDE:   43°  5.1' N (  43.08550)          LONGITUDE:  79°  3.9' W ( -79.06506)


The primary bench mark is a disk located 17.40 m (57.1 ft) W of curb of Robert
Moses Parkway, 15.90 m (52.2 ft) N of the drain gate located in Niagara Falls
Park, and 13.10 m (43.0 ft) S of face of Korean Conflict Monument. The datum
point is set 0.15 m (0.5 ft) below the ground, being crimped to a 5/8-inch
stainless steel rod driven 2.7 m (9 ft) to refusal, encased in a 5-inch PVC pipe
and concrete kickblock with witness post.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  2 of  5

                                                                                
Station ID: 9063009                         PUBLICATION DATE:  08/11/2017
Name:       AMERICAN FALLS, NIAGARA FALLS, NIAGARA R          
            NY
NOAA Chart: 14822                           Latitude:   43°  4.9' N (  43.08106)
USGS Quad:                                  Longitude:  79°  3.7' W ( -79.06136)


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


                         BENCH MARK STAMPING:  V 411 1977
                         DESIGNATION:          V 411

MONUMENTATION:           Bench Mark disk                       VM#:        12767
AGENCY:                  National Geodetic Survey (NGS)        IDB PID#:  OG0347
SETTING CLASSIFICATION:  Concrete and stone wing wall          OPUS PID:        
LATITUDE:   43°  4.9' N (  43.08086)          LONGITUDE:  79°  3.6' W ( -79.05983)


The bench mark is a disk set in top of concrete and stone wing wall located
30.00 m (98.4 ft) SSW of the centerline of the E bound lanes of Robert Moses
Parkway, 13.90 m (45.6 ft) SE of the NE corner nearest the door of the
hexagonal-shaped NOAA water level gauge house and  3.39 m (11.12 ft) W of E edge
of concrete catch basin wall.



                         BENCH MARK STAMPING:  FALLS A 1976
                         DESIGNATION:          906 3009 FALLS A

MONUMENTATION:           Bench Mark disk                       VM#:        12768
AGENCY:                  US Army Corp of Engineers (USACE)     IDB PID#:  OG0348
SETTING CLASSIFICATION:  Gauge House                           OPUS PID:        
LATITUDE:   43°  4.9' N (  43.08106)          LONGITUDE:  79°  3.7' W ( -79.06136)


The bench mark is set vertically in the upstream side of the hexagonal shaped
stone gage house, 12.35 m (40.5 ft) W of the W edge of the concrete catch basin
wall, 4.32 m (14.2 ft) S of the centerline of a asphalt walkway running E and W
along rivers edge, 0.30 m (1.0 ft) from the NE corner nearest doorway, and 1.20
m (3.9 ft) above the ground.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  3 of  5

                                                                                
Station ID: 9063009                         PUBLICATION DATE:  08/11/2017
Name:       AMERICAN FALLS, NIAGARA FALLS, NIAGARA R          
            NY
NOAA Chart: 14822                           Latitude:   43°  4.9' N (  43.08106)
USGS Quad:                                  Longitude:  79°  3.7' W ( -79.06136)


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


                         BENCH MARK STAMPING:   
                         DESIGNATION:          906 3009 GRATE

MONUMENTATION:           Chiseled Square                       VM#:        12769
AGENCY:                                                        IDB PID#:  OG0222
SETTING CLASSIFICATION:  Concrete catch basin foundation       OPUS PID:        
LATITUDE:   43°  4.9' N (  43.08200)          LONGITUDE:  79°  3.7' W ( -79.06092)


The bench mark is a chiseled square being the highest point in a 1-inch square
formed by two chiseled lines on the SE corner of the foundation located 8.70 m
(28.5 ft) NE of N curb of Robert Moses Parkway, 3.00 m (9.8 ft) SE of a 25-inch
diameter maple tree, and 1.00 m (3.3 ft) S of NE corner of the concrete catch
basin foundation.



                         BENCH MARK STAMPING:   
                         DESIGNATION:          906 3009 PARK

MONUMENTATION:           Bolt                                  VM#:        12771
AGENCY:                                                        IDB PID#:  OG0227
SETTING CLASSIFICATION:  Window sill                           OPUS PID:        
LATITUDE:   43°  5.2' N (  43.08672)          LONGITUDE:  79°  3.9' W ( -79.06547)


The bench mark is a bolt set under the most N window sill in the water table,
37.52m (123.1 ft) W of center falg pole of 3 flag poles that are located in the
countyard of Administration Office and Visitors Center, 11.70 m (38.4 ft) N of
the centerline of the main entrance to the Administration office, 3.10 m (10.2
ft) S of the NE corner and in E face of administration building, and 0.66 m (2.1
ft) above the 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  4 of  5

                                                                                
Station ID: 9063009                         PUBLICATION DATE:  08/11/2017
Name:       AMERICAN FALLS, NIAGARA FALLS, NIAGARA R          
            NY
NOAA Chart: 14822                           Latitude:   43°  4.9' N (  43.08106)
USGS Quad:                                  Longitude:  79°  3.7' W ( -79.06136)


                             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  5 of  5

                                                                                
Station ID: 9063009                         PUBLICATION DATE:  08/11/2017
Name:       AMERICAN FALLS, NIAGARA FALLS, NIAGARA R          
            NY
NOAA Chart: 14822                           Latitude:   43°  4.9' N (  43.08106)
USGS Quad:                                  Longitude:  79°  3.7' W ( -79.06136)


                             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/.