U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Datums Page Page 1 of 5 Station ID: 9465283 PUBLICATION DATE: 03/19/2019 Name: NE SIDE SUMMIT ISLAND, TOGIAK BAY A AK NOAA Chart: Latitude: 58° 50.8' N ( 58.84670) USGS Quad: Longitude: 160° 12.6' W (-160.21001) T I D A L B E N C H M A R K S PRIMARY BENCH MARK STAMPING: 5283 D 1986 DESIGNATION: 946 5283 D 1986 MONUMENTATION: Survey disk VM#: 15351 AGENCY: National Ocean Service (NOS) IDB PID: SETTING CLASSIFICATION: Bedrock OPUS PID: LATITUDE: 58° 50.8' N ( 58.84670) LONGITUDE: 160° 12.6' W (-160.21000) The primary bench mark is a disk which lies in bedrock 0.91 m (3.0 ft) east of the bluff about 0.61 m (2.0 ft) above the gravel, in a cove on the NE side of Summit Island, 1.83 m (6.0 ft) north of a rock wall that extends from a grassy bluff, 200 m (656 ft) NW (350 magnetic) from bench mark 5283 C 1986 and 35.66 m (117.0 ft) from bench mark 5283 E 1986. BENCH MARK STAMPING: 5283 A 1986 DESIGNATION: 946 5283 A 1986 MONUMENTATION: Survey disk VM#: 15348 AGENCY: National Ocean Service (NOS) IDB PID: SETTING CLASSIFICATION: North face of a rocky point OPUS PID: LATITUDE: 58° 50.8' N ( 58.84670) LONGITUDE: 160° 12.6' W (-160.21000) The bench mark is a disk located in a cove on the NE side of Summit Island, on the north face of a rocky point which is north of the point at the southern limit of the cove, 0.15 m (0.5 ft) above the gravel by the large boulders, about 27 m (88 ft) SE (120 magnetic) from bench mark 5283 B 1986. Bench mark 5283 A 1986 is not visible from bench mark 5283 B 1986.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 2 of 5 Station ID: 9465283 PUBLICATION DATE: 03/19/2019 Name: NE SIDE SUMMIT ISLAND, TOGIAK BAY A AK NOAA Chart: Latitude: 58° 50.8' N ( 58.84670) USGS Quad: Longitude: 160° 12.6' W (-160.21001) T I D A L B E N C H M A R K S BENCH MARK STAMPING: 5283 B 1986 DESIGNATION: 946 5283 B 1986 MONUMENTATION: Survey disk VM#: 15349 AGENCY: National Ocean Service (NOS) IDB PID: SETTING CLASSIFICATION: Bedrock OPUS PID: LATITUDE: 58° 50.8' N ( 58.84670) LONGITUDE: 160° 12.6' W (-160.21000) The bench mark is a disk located in bedrock in a cove on the NE side of Summit Island which rock lies on the north side of the northernmost point on the south end of the cove, 0.61 m (2.0 ft) above the approximate high water line and about 0.3 m (1 ft) above the gravel at the foot of a chimney, 53.60 m (176.0 ft) SE (145 magnetic) from bench mark 5283 C 1986. Bench mark 5283 B 1986 is not visible from bench mark 5283 A 1986 but is about 27 m (88 ft) NW (300 magnetic) from bench mark 5283 A 1986. BENCH MARK STAMPING: 5283 C 1986 DESIGNATION: 946 5283 C 1986 MONUMENTATION: Survey disk VM#: 15350 AGENCY: National Ocean Service (NOS) IDB PID: SETTING CLASSIFICATION: Outcrop of bedrock OPUS PID: LATITUDE: 58° 50.8' N ( 58.84670) LONGITUDE: 160° 12.6' W (-160.21000) The bench mark is a disk lies in a cove on the NE side of Summit Island, about 30.0 m (98.4 ft) south of a creek that runs by a sauna in an outcrop of bedrock which is about 9.0 m (29.5 ft) east of a grassy ridge, 0.15 m (0.5 ft) above the gravel, 54 m (176 ft) NW (325 magnetic) from bench mark 5283 B 1986, 200 m (656 ft) SE (170 magnetic) from bench mark 5283 D 1986, although it is not visible.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 3 of 5 Station ID: 9465283 PUBLICATION DATE: 03/19/2019 Name: NE SIDE SUMMIT ISLAND, TOGIAK BAY A AK NOAA Chart: Latitude: 58° 50.8' N ( 58.84670) USGS Quad: Longitude: 160° 12.6' W (-160.21001) T I D A L B E N C H M A R K S BENCH MARK STAMPING: 5283 E 1986 DESIGNATION: 946 5283 E 1986 MONUMENTATION: Survey disk VM#: 15352 AGENCY: National Ocean Service (NOS) IDB PID: SETTING CLASSIFICATION: Bedrock OPUS PID: LATITUDE: 58° 50.8' N ( 58.84670) LONGITUDE: 160° 12.6' W (-160.21000) The bench mark is a disk which lies in bedrock on the southern face of a rocky point on the north end of the cove, on the north end of a cove on the NE side of Summit Island, 0.91 m (3.0 ft) above the gravel, 35.65 m (117.0 ft) north (000 magnetic) from bench mark 5283 D 1986.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 4 of 5 Station ID: 9465283 PUBLICATION DATE: 03/19/2019 Name: NE SIDE SUMMIT ISLAND, TOGIAK BAY A AK NOAA Chart: Latitude: 58° 50.8' N ( 58.84670) USGS Quad: Longitude: 160° 12.6' W (-160.21001) T I D A L D A T U M S Tidal datums at NE SIDE SUMMIT ISLAND, TOGIAK BAY A based on: LENGTH OF SERIES: 2 MONTHS TIME PERIOD: June 1988 - July 1988 TIDAL EPOCH: 1983-2001 CONTROL TIDE STATION: 9463502 PORT MOLLER, BRISTOL BAY Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS: MEAN HIGHER HIGH WATER MHHW = 3.239 MEAN HIGH WATER MHW = 2.878 MEAN SEA LEVEL MSL = 1.735 MEAN TIDE LEVEL MTL = 1.667 MEAN LOW WATER MLW = 0.455 MEAN LOWER LOW WATER MLLW = 0.000 Bench Mark Elevation Information In METERS above: Stamping or Designation MLLW MHW 5283 D 1986 7.744 4.866 5283 A 1986 6.705 3.827 5283 B 1986 7.275 4.397 5283 C 1986 6.919 4.041 5283 E 1986 6.953 4.075 Foot Notes: Data from this station was collected using methodology that does not meet CO-OPS highest level of accuracy (no more than 10 cm, 95% Confidence Interval (CI) referenced to a tidal datum). Recognizing that lower quality data can be used for certain applications CO-OPS is making this data available to its users with restraint. The average six-minute water level observations derived from this system have an accuracy ranging from 10.0 - 30.0 cm, 95% CI on datum. Users are cautioned to consider the accuracy of these data before using them for critical navigational or coastal engineering purposes.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 5 of 5 Station ID: 9465283 PUBLICATION DATE: 03/19/2019 Name: NE SIDE SUMMIT ISLAND, TOGIAK BAY A AK NOAA Chart: Latitude: 58° 50.8' N ( 58.84670) USGS Quad: Longitude: 160° 12.6' W (-160.21001) D E F I N I T I O N S Mean Sea Level (MSL) is a tidal datum determined over a 19-year National Tidal Datum Epoch. It pertains to local mean sea level and should not be confused with the fixed datums of North American Vertical Datum of 1988 (NAVD88). 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 to NAVD88 are available from NGS through the World Wide Web at National Geodetic Survey. NGVD29 is a fixed datum adopted as a national standard geodetic reference for heights but is now considered superseded. NGVD29 is sometimes referred to as Sea Level Datum of 1929 or as Mean Sea Level on some early issues of Geological Survey Topographic Quads. NGVD29 was originally derived from a general adjustment of the first-order leveling networks of the U.S. and Canada after holding mean sea level observed at 26 long term tide stations as fixed. Numerous local and wide-spread adjustments have been made since establishment in 1929. Bench mark elevations relative to NGVD29 are available from the National Geodetic Survey (NGS) data base via the World Wide Web at National Geodetic Survey. NAVD88 and NGVD29 are fixed geodetic datums whose elevation relationships to local MSL and other tidal datums may not be consistent from one location to another. 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/. The NAVD88 elevation is shown on the Elevations of Tidal Datums Table Referred to MLLW only when two or more of the bench marks listed have NAVD88 elevations. The NAVD88 elevation relationship shown in the table is derived from an average of several bench mark elevations relative to tide station datum. As a result of this averaging, NAVD88 bench mark elevations computed indirectly from the tidal datums elevation table may differ slightly from NAVD88 elevations listed for each bench mark in the NGS database.