U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Datums Page Page 1 of 5 Station ID: 9450495 PUBLICATION DATE: 06/28/2004 Name: SALTERY COVE, SKOWL ARM AK NOAA Chart: 17426 Latitude: 55° 24.1' N ( 55.40170) USGS Quad: CRAIG (B-1) Longitude: 132° 19.7' W (-132.32800) To reach the tidal bench marks from Ketchikan, Alaska, proceed 43.5 km (23.5 nm) WNW by a float plane or boat to the confluence of Skowl Arm and McKenzie Inlet on Prince of Wales Island and Saltery Cove is located nearby. The tidal bench marks are on the beach at the head of Saltery Cove. The tide gauge was located on the beach. T I D A L B E N C H M A R K S PRIMARY BENCH MARK STAMPING: NO 5 1958 DESIGNATION: 945 0495 TIDAL 5 MONUMENTATION: Tidal Station disk VM#: 17416 AGENCY: US Coast and Geodetic Survey (USC&GS) IDB PID#: SETTING CLASSIFICATION: Rock outcrop OPUS PID: LATITUDE: 55° 24.1' N ( 55.40170) LONGITUDE: 132° 19.7' W (-132.32800) The primary bench mark is a disk set in top of a flat rock outcrop on a rocky point, 114 m (372 ft) SE of bench mark NO 2 1921, 5 m (15 ft) east of old engine parts, under the NE corner of the main ruins of cannery on the west shore of Saltery Cove, and just below the apparent high water line.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 2 of 5 Station ID: 9450495 PUBLICATION DATE: 06/28/2004 Name: SALTERY COVE, SKOWL ARM AK NOAA Chart: 17426 Latitude: 55° 24.1' N ( 55.40170) USGS Quad: CRAIG (B-1) Longitude: 132° 19.7' W (-132.32800) T I D A L B E N C H M A R K S BENCH MARK STAMPING: NO 2 1921 DESIGNATION: 945 0495 TIDAL 2 MONUMENTATION: Tidal Station disk VM#: 17413 AGENCY: US Coast and Geodetic Survey (USC&GS) IDB PID#: SETTING CLASSIFICATION: Rocky ledge OPUS PID: LATITUDE: 55° 24.1' N ( 55.40170) LONGITUDE: 132° 19.7' W (-132.32800) The bench mark is a disk set in a flat spot on a rocky ledge, 114 m (372 ft) NW of bench mark NO 5 1958, slightly above apparent high water line, and below the bluff on which the ruins of two cottages are located. BENCH MARK STAMPING: NO 3 1921 DESIGNATION: 945 0495 TIDAL 3 MONUMENTATION: Tidal Station disk VM#: 17414 AGENCY: US Coast and Geodetic Survey (USC&GS) IDB PID#: SETTING CLASSIFICATION: Rock outcrop OPUS PID: LATITUDE: 55° 24.1' N ( 55.40170) LONGITUDE: 132° 19.7' W (-132.32800) The bench mark is a disk set in a rock outcrop, 80 m (262 ft) NW of bench mark NO 6 1959, 30 m (100 ft) north of another clump of rocks, SE across the head of Saltery Cove from bench mark NO 5 1958, in the NW section of a clump of rocks on low point, and at the apparent high water line.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 3 of 5 Station ID: 9450495 PUBLICATION DATE: 06/28/2004 Name: SALTERY COVE, SKOWL ARM AK NOAA Chart: 17426 Latitude: 55° 24.1' N ( 55.40170) USGS Quad: CRAIG (B-1) Longitude: 132° 19.7' W (-132.32800) T I D A L B E N C H M A R K S BENCH MARK STAMPING: NO 4 1958 DESIGNATION: 945 0495 TIDAL 4 MONUMENTATION: Tidal Station disk VM#: 17415 AGENCY: US Coast and Geodetic Survey (USC&GS) IDB PID#: SETTING CLASSIFICATION: Top of a rock OPUS PID: LATITUDE: 55° 24.1' N ( 55.40170) LONGITUDE: 132° 19.7' W (-132.32800) The bench mark is a disk set in top of a rock, 130 m (426 ft) SW of bench mark NO 6 1959, 122 m (400 ft) SW of a clump of rocks with a 6 m (20 ft) tall cedar tree and 5 m (15 ft) tall spruce tree, 46 m (150 ft) north of the tree line at the head of Saltery Cove, and 6 m (20 ft) east of a small stream at the low water. BENCH MARK STAMPING: NO 6 1959 DESIGNATION: 945 0495 TIDAL 6 MONUMENTATION: Tidal Station disk VM#: 17417 AGENCY: US Coast and Geodetic Survey (USC&GS) IDB PID#: SETTING CLASSIFICATION: Rock outcrop OPUS PID: LATITUDE: 55° 24.1' N ( 55.40170) LONGITUDE: 132° 19.7' W (-132.32800) The bench mark is a disk set in top of a rock outcrop, 130 m (426 ft) NE of bench mark NO 4 1958, 80 m (262 ft) SE of bench mark NO 3 1921, 21 m (70 ft) SSE of a 6 m (20 ft) tall cedar tree and a 5 m (15 ft) tall spruce tree, on the clump of rocks at the head of Saltery Cove, and just below the highest point of the highest rock in the outcrop.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 4 of 5 Station ID: 9450495 PUBLICATION DATE: 06/28/2004 Name: SALTERY COVE, SKOWL ARM AK NOAA Chart: 17426 Latitude: 55° 24.1' N ( 55.40170) USGS Quad: CRAIG (B-1) Longitude: 132° 19.7' W (-132.32800) T I D A L D A T U M S Tidal datums at SALTERY COVE, SKOWL ARM based on: LENGTH OF SERIES: 1 MONTH TIME PERIOD: August 2003 - August 2003 TIDAL EPOCH: 1983-2001 CONTROL TIDE STATION: 9450460 KETCHIKAN, TONGASS NARROWS Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS: MEAN HIGHER HIGH WATER MHHW = 4.746 MEAN HIGH WATER MHW = 4.469 MEAN TIDE LEVEL MTL = 2.477 MEAN SEA LEVEL MSL = 2.473 MEAN LOW WATER MLW = 0.485 MEAN LOWER LOW WATER MLLW = 0.000 North American Vertical Datum (NAVD88) Bench Mark Elevation Information In METERS above: Stamping or Designation MLLW MHW NO 5 1958 4.530 0.061 NO 2 1921 5.434 0.965 NO 3 1921 4.640 0.171 NO 4 1958 3.812 -0.657 NO 6 1959 5.631 1.162
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 5 of 5 Station ID: 9450495 PUBLICATION DATE: 06/28/2004 Name: SALTERY COVE, SKOWL ARM AK NOAA Chart: 17426 Latitude: 55° 24.1' N ( 55.40170) USGS Quad: CRAIG (B-1) Longitude: 132° 19.7' W (-132.32800) 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.