U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Datums Page Page 1 of 6 Station ID: 9458907 PUBLICATION DATE: 04/21/2003 Name: CASTLE BAY AK NOAA Chart: 16566 Latitude: 56° 13.9' N ( 56.23170) USGS Quad: CHIGNIK (A-1) Longitude: 158° 20.6' W (-158.34300) To reach the tidal bench marks from Chignik via boat, proceed NNE out of Anchorage Bay 6.0 km (3.2 nm), then ESE 15 km (8 nm) to Jack Point, then WSW 15 km (8 nm) along the north shore of Castle Bay to the head of the NW Arm and a small curve of flat land which projects south from the mainland. Four of the bench marks are located east of the point along a rock cliff shore. The remaining bench marks are on the flat land, inland from the shore. The tide station was located at the top of the stone beach, just east of where the beach curves to the south. T I D A L B E N C H M A R K S PRIMARY BENCH MARK STAMPING: 8907 B 2001 DESIGNATION: 945 8907 B MONUMENTATION: Tidal Station disk VM#: 16595 AGENCY: National Ocean Service (NOS) IDB PID#: SETTING CLASSIFICATION: Rock outcrop OPUS PID: LATITUDE: 56° 13.9' N ( 56.23170) LONGITUDE: 158° 20.6' W (-158.34300) The primary bench mark is a disk set in a drill hole in a rock outcrop at the west end of the rock cliff shore, 203.28 m (666.9 ft) east of bench mark 8907 A 2001, 25.12 m (82.4 ft) WSW of bench mark 8907 C 2001, 1.50 m (4.9 ft) below the vegetation line, 0.50 m (1.6 ft) south of the vertical rock face, and 0.20 m (0.7 ft) above the stone beach.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 2 of 6 Station ID: 9458907 PUBLICATION DATE: 04/21/2003 Name: CASTLE BAY AK NOAA Chart: 16566 Latitude: 56° 13.9' N ( 56.23170) USGS Quad: CHIGNIK (A-1) Longitude: 158° 20.6' W (-158.34300) T I D A L B E N C H M A R K S BENCH MARK STAMPING: 8907 A 2001 DESIGNATION: 945 8907 A MONUMENTATION: Flange-encased Rod VM#: 16594 AGENCY: National Ocean Service (NOS) IDB PID#: SETTING CLASSIFICATION: Stainless steel rod OPUS PID: LATITUDE: 56° 13.9' N ( 56.23170) LONGITUDE: 158° 20.6' W (-158.34300) The bench mark is a stainless steel rod located on a small rise inland from where the shoreline curves out to the south, 214.60 m (704.1 ft) ENE of bench mark New 1924, 203.28 m (666.9 ft) west of bench mark 8907 B 2001, 68 m (223 ft) north of the stone beach, and 11 m (36 ft) north of a low sand depression. The datum point is set 0.03 m (0.1 ft) below ground, being the top of a stainless steel rod with a rounded top and punchmark in the center, driven 6.7 m (22 ft) to refusal, and encased in a 5-inch PVC pipe with aluminum NOS logo cap. BENCH MARK STAMPING: 8907 C 2001 DESIGNATION: 945 8907 C MONUMENTATION: Tidal Station disk VM#: 16596 AGENCY: National Ocean Service (NOS) IDB PID#: SETTING CLASSIFICATION: Rock outcrop OPUS PID: LATITUDE: 56° 13.9' N ( 56.23170) LONGITUDE: 158° 20.6' W (-158.34300) The bench mark is a disk set in a drill hole in a rock outcrop along a rock cliff shore, 38.32 m (125.7 ft) WSW of bench mark 8907 D 2001, 25.12 m (82.4 ft) east of bench mark 8907 B 2001, 3.5 m (11.5 ft) below the vegetation line, 2.0 m (6.6 ft) east of a narrow recess in the rock wall, and 1.0 m (3.3 ft) above the rock beach.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 3 of 6 Station ID: 9458907 PUBLICATION DATE: 04/21/2003 Name: CASTLE BAY AK NOAA Chart: 16566 Latitude: 56° 13.9' N ( 56.23170) USGS Quad: CHIGNIK (A-1) Longitude: 158° 20.6' W (-158.34300) T I D A L B E N C H M A R K S BENCH MARK STAMPING: 8907 D 2001 DESIGNATION: 945 8907 D MONUMENTATION: Tidal Station disk VM#: 16597 AGENCY: National Ocean Service (NOS) IDB PID#: SETTING CLASSIFICATION: Rock outcrop OPUS PID: LATITUDE: 56° 13.9' N ( 56.23170) LONGITUDE: 158° 20.6' W (-158.34300) The bench mark is a disk set in a drill hole in a flat, gray rock outcrop along a rock cliff shore, 51.64 m (169.4 ft) WSW of bench mark 8907 E 2001, 38.32 m (125.7 ft) ENE of bench mark 8907 C 2001, 13.0 m (42.7 ft) west of an intermittent waterfall, 2.70 m (8.9 ft) south of the cliff face, and 4 m (13 ft) below the top of the cliff. BENCH MARK STAMPING: 8907 E 2001 DESIGNATION: 945 8907 E MONUMENTATION: Tidal Station disk VM#: 16598 AGENCY: National Ocean Service (NOS) IDB PID#: SETTING CLASSIFICATION: Rock outcrop OPUS PID: LATITUDE: 56° 13.9' N ( 56.23170) LONGITUDE: 158° 20.6' W (-158.34300) The bench mark is a disk set in a drill hole in a flat, black rock outcrop along a rock cliff shore, 51.64 m (169.4 ft) ENE of bench mark 8907 D 2001, 3.0 m (9.8 ft) south of the cliff face, and level with the boulder beach.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 4 of 6 Station ID: 9458907 PUBLICATION DATE: 04/21/2003 Name: CASTLE BAY AK NOAA Chart: 16566 Latitude: 56° 13.9' N ( 56.23170) USGS Quad: CHIGNIK (A-1) Longitude: 158° 20.6' W (-158.34300) T I D A L B E N C H M A R K S BENCH MARK STAMPING: NEW 1924 DESIGNATION: 945 8907 NEW MONUMENTATION: Triangulation Station disk VM#: 16608 AGENCY: US Coast and Geodetic Survey (USC&GS) IDB PID#: SETTING CLASSIFICATION: Boulder OPUS PID: LATITUDE: 56° 13.9' N ( 56.23170) LONGITUDE: 158° 20.6' W (-158.34300) The bench mark is a disk set in a 0.40 m x 0.50 m (1.3 ft x 1.6 ft) boulder, 214.60 m (704.1 ft) WSW of bench mark 8907 A 2001, 22.33 m (73.3 ft) ESE of bench mark NEW RM 1 1924, 9.24 m (30.3 ft) north of the edge of vegetation along the stone beach, and flush with the ground. BENCH MARK STAMPING: RM 1 1924 DESIGNATION: 945 8907 RM 1 MONUMENTATION: Reference Mark disk VM#: 16610 AGENCY: US Coast and Geodetic Survey (USC&GS) IDB PID#: SETTING CLASSIFICATION: Boulder OPUS PID: LATITUDE: 56° 13.8' N ( 56.23000) LONGITUDE: 158° 20.6' W (-158.34300) The bench mark is a disk set in a 1 m x 0.25 m (2 ft x 0.8 ft) oblong boulder, 22.33 m (73.3 ft) WNW of bench mark NEW 1924, 9.9 m (32.5 ft) north of the edge of vegetation along the stone beach, and flush with the ground.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 5 of 6 Station ID: 9458907 PUBLICATION DATE: 04/21/2003 Name: CASTLE BAY AK NOAA Chart: 16566 Latitude: 56° 13.9' N ( 56.23170) USGS Quad: CHIGNIK (A-1) Longitude: 158° 20.6' W (-158.34300) T I D A L D A T U M S Tidal datums at CASTLE BAY based on: LENGTH OF SERIES: 1 Month TIME PERIOD: July 2001 - July 2001 TIDAL EPOCH: 1983-2001 CONTROL TIDE STATION: 9459450 SAND POINT, POPOF ISLAND Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS: MEAN HIGHER HIGH WATER MHHW = 2.689 MEAN HIGH WATER MHW = 2.441 MEAN TIDE LEVEL MTL = 1.439 MEAN SEA LEVEL MSL = 1.417 MEAN LOW WATER MLW = 0.437 MEAN LOWER LOW WATER MLLW = 0.000 North American Vertical Datum (NAVD88) Bench Mark Elevation Information In METERS above: Stamping or Designation MLLW MHW 8907 B 2001 4.353 1.912 8907 A 2001 7.875 5.434 8907 C 2001 4.077 1.636 8907 D 2001 2.920 0.479 8907 E 2001 2.116 -0.325 NEW 1924 5.884 3.443 RM 1 1924 5.907 3.466
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 6 of 6 Station ID: 9458907 PUBLICATION DATE: 04/21/2003 Name: CASTLE BAY AK NOAA Chart: 16566 Latitude: 56° 13.9' N ( 56.23170) USGS Quad: CHIGNIK (A-1) Longitude: 158° 20.6' W (-158.34300) 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.