U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Datums Page Page 1 of 8 Station ID: 9451054 PUBLICATION DATE: 12/15/2020 Name: PORT ALEXANDER, BARANOF ISLAND AK NOAA Chart: 17331 Latitude: 56° 14.8' N ( 56.24670) USGS Quad: PORT ALEXANDER Longitude: 134° 38.8' W (-134.64700) From the seaplane base at Sitka, Alaska, proceed 120 km (65 nm) SSE to the community of Port Alexander. From the seaplane float located on the east side of the outer cove, proceed 120 m (400 ft) up the state dock towards the boardwalk. The tide house is located at the base of the fixed pier at the start of the boardwalk. The bench marks are located along the shoreline of the inner cove and out to the point forming the entrance to Port Alexander. T I D A L B E N C H M A R K S PRIMARY BENCH MARK STAMPING: DESIGNATION: 945 1054 TIDAL 1 MONUMENTATION: Tidal Station disk VM#: 18470 AGENCY: US Coast and Geodetic Survery (USC&GS) IDB PID: SETTING CLASSIFICATION: Rock outcrop OPUS PID#: BBDC38 LATITUDE: 56° 14.7' N ( 56.24522) LONGITUDE: 134° 38.8' W (-134.64742) The primary bench mark is a disk set flush in the highest flat point of a bedrock outcropping at the end of the trail leading south from Port Alexander on the east side of the bay, 40.95 m (134.3 ft) SSE of the west corner 12" piling bracing the 2.15 m (7.1 ft) high bulkhead supporting the ACS/Alascom satellite dish, 30.70 m (100.7 ft) NW of the center of the concrete pad supporting the Earth Scope plate tectonic GPS station antenna, 8.30 m (27.2 ft) north of the north edge of the F/V Sarah Maria memorial plaque, and 0.70 m (2.3 ft) above beach level.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 2 of 8 Station ID: 9451054 PUBLICATION DATE: 12/15/2020 Name: PORT ALEXANDER, BARANOF ISLAND AK NOAA Chart: 17331 Latitude: 56° 14.8' N ( 56.24670) USGS Quad: PORT ALEXANDER Longitude: 134° 38.8' W (-134.64700) T I D A L B E N C H M A R K S BENCH MARK STAMPING: 2 1924 DESIGNATION: 945 1054 TIDAL 2 MONUMENTATION: Tidal Station disk VM#: 18471 AGENCY: US Coast and Geodetic Survey (USC&GS) IDB PID: SETTING CLASSIFICATION: Rock outcrop OPUS PID#: BBFG13 LATITUDE: 56° 14.7' N ( 56.24508) LONGITUDE: 134° 38.8' W (-134.64722) The bench mark is a disk set in a bedrock ledge 33.2 m (108.9 ft) SSE of bench mark TIDAL 1, 15.4 m (50.50 ft) NNE of TIDAL J, 19.5 m (64.00 ft) SSW of center of Unavco GPS antenna, flush with rock surface and subject to periodic burial by gravel beach deposits. BENCH MARK STAMPING: 1054 A 2007 DESIGNATION: 945 1054 A MONUMENTATION: Bench Mark disk VM#: 18472 AGENCY: National Ocean Service (NOS) IDB PID: SETTING CLASSIFICATION: Concrete slab OPUS PID: LATITUDE: 56° 14.8' N ( 56.24661) LONGITUDE: 134° 38.9' W (-134.64769) The bench mark is a disk set flush in the SW corner of the 1.83 m x 2.44 m (6.0 ft x 8.0 ft) concrete slab supporting the tide house, 24.60 m (80.7 ft) WSW of the south leg of the microwave tower on the east side of the bay at Port Alexander, 20.23 m (66.4 ft) NE of a brown wooden building that houses the generator that powers the ACS/Alascom equipment, 3.39 m (11.1 ft) south of the south side of the boardwalk leading out to the city pier, 0.31 m (1.0 ft) north of the south edge of the concrete slab and 0.18 m (0.60 ft) east of the west edge of the concrete slab. Note - This bench mark is also used as the Met TBM for this station.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 3 of 8 Station ID: 9451054 PUBLICATION DATE: 12/15/2020 Name: PORT ALEXANDER, BARANOF ISLAND AK NOAA Chart: 17331 Latitude: 56° 14.8' N ( 56.24670) USGS Quad: PORT ALEXANDER Longitude: 134° 38.8' W (-134.64700) T I D A L B E N C H M A R K S BENCH MARK STAMPING: 1054 B 2007 DESIGNATION: 945 1054 B MONUMENTATION: Bench Mark disk VM#: 18473 AGENCY: National Ocean Service (NOS) IDB PID: SETTING CLASSIFICATION: Concrete slab OPUS PID: LATITUDE: 56° 14.9' N ( 56.24750) LONGITUDE: 134° 38.8' W (-134.64722) The bench mark is a disk set flush in the north side of the flat section of a concrete boat ramp, 9.42 m (30.9 ft) NNW of the NE corner of a large green and brown house with a metal garage door facing the bay, 7.35 m (24.1 ft) WSW of the SW corner of the "J&L Gifts and Antiques" building, 2.46 m (8.1 ft) north of the SW end of a wooden retaining wall and 1.50 m (4.9 ft) east of the approximate high water line. BENCH MARK STAMPING: 1054 C 2007 DESIGNATION: 945 1054 C MONUMENTATION: Bench Mark disk VM#: 18474 AGENCY: National Ocean Service (NOS) IDB PID: SETTING CLASSIFICATION: Rock outcrop OPUS PID: LATITUDE: 56° 14.9' N ( 56.24858) LONGITUDE: 134° 38.9' W (-134.64772) The bench mark is a disk set flush in a small crevice of a flat-topped rock outcrop, 23.94 m (78.5 ft) NNW of the NW corner of the gray house belonging to Juanita Hendrix, 18.62 m (61.1 ft) WSW of the west side of the small boardwalk that splits off the main boardwalk and leads to a gray wooden out-building with a wooden ramp leading to the water next door to the gray house, 15.64 m (51.3 ft) south of the SW corner of the gray wooden out-building with a wooden ramp leading to the water next door to the gray house.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 4 of 8 Station ID: 9451054 PUBLICATION DATE: 12/15/2020 Name: PORT ALEXANDER, BARANOF ISLAND AK NOAA Chart: 17331 Latitude: 56° 14.8' N ( 56.24670) USGS Quad: PORT ALEXANDER Longitude: 134° 38.8' W (-134.64700) T I D A L B E N C H M A R K S BENCH MARK STAMPING: 1054 D 2007 DESIGNATION: 945 1054 D MONUMENTATION: Bench Mark disk VM#: 18475 AGENCY: National Ocean Survey (NOS) IDB PID: SETTING CLASSIFICATION: Bedrock outcrop OPUS PID: LATITUDE: 56° 14.9' N ( 56.24853) LONGITUDE: 134° 38.8' W (-134.64728) The bench mark is a disk set flush in a flat ledge of a large bedrock outcrop on the east side of the boardwalk, 11.33 m (37.2 ft) north of the north corner of a small gray wooden fuel shed on the west side of the boardwalk, 9.77 m (32.1 ft) south of the south side of the first entrance to the "Laughing Raven Lodge" where the boardwalk angles up the hill, 8.58 m (28.1 ft) east of NE corner of the gray house, 0.23 m (0.8 ft) east of the east side of the boardwalk, and 0.55 m (1.8 ft) above the boardwalk. BENCH MARK STAMPING: 1054 E 2007 DESIGNATION: 945 1054 E MONUMENTATION: Bench Mark disk VM#: 18476 AGENCY: National Ocean Service (NOS) IDB PID: SETTING CLASSIFICATION: Rock outcrop OPUS PID: LATITUDE: 56° 14.7' N ( 56.24486) LONGITUDE: 134° 38.7' W (-134.64583) The bench mark is a disk set flush in a rock outcrop on the west side of a low-lying saddle between the point on the east side of the entrance to Port Alexander locally known as "the point" and a small rocky headland with trees and shrubs, 74.70 m (245.1 ft) east of the center of the concrete pad supporting the Earth Scope plate tectonic GPS station antenna, 25.30 m (83.0 ft) SW of the point on the east side of the entrance to Port Alexander locally known as "the point", and 12.05 m (39.5 ft) NNE of the north end of the small 7.00 m by 23.00 m (23.0 ft by 75.5 ft) headland with trees and shrubs just south of "the point".
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 5 of 8 Station ID: 9451054 PUBLICATION DATE: 12/15/2020 Name: PORT ALEXANDER, BARANOF ISLAND AK NOAA Chart: 17331 Latitude: 56° 14.8' N ( 56.24670) USGS Quad: PORT ALEXANDER Longitude: 134° 38.8' W (-134.64700) T I D A L B E N C H M A R K S BENCH MARK STAMPING: 1054 F 2007 DESIGNATION: 945 1054 F MONUMENTATION: Bench Mark disk VM#: 18477 AGENCY: National Ocean Service (NOS) IDB PID: SETTING CLASSIFICATION: Rock outcrop OPUS PID: LATITUDE: 56° 14.7' N ( 56.24419) LONGITUDE: 134° 38.8' W (-134.64614) The bench mark is a disk set flush in a rock outcrop on the east side of the entrance to Port Alexander, 100.91 m (331.1 ft) SSW of bench mark 945 1054 H, 84.17 m (276.1 ft) ENE of bench mark 945 1054 G, 79.25 m (260.0 ft) ENE of bench mark 945 1054 E, and 1.00 m (3.3 ft) above the approximate high water line ans 2.4 m (7.9 ft) E of a white metal witness post sign. BENCH MARK STAMPING: 1054 G 2007 DESIGNATION: 945 1054 G MONUMENTATION: Tidal Station disk VM#: 18478 AGENCY: National Ocean Service (NOS) IDB PID: SETTING CLASSIFICATION: Rock outcrop OPUS PID: LATITUDE: 56° 14.6' N ( 56.24392) LONGITUDE: 134° 38.8' W (-134.64739) The bench mark is a disk set flush in a rock ledge on the NE corner of the largest tree headland on the east side of the entrance to Port Alexander, 84.17 m (276.1 ft) WSW of bench mark 945 1054 F, 59.9 m (196.5 ft) NNW of a 0.90 m x 0.40 m x 0.60 m high (3.0 ft x 1.3 ft x 2.0 ft) Quartzite projection on a prominent vein that is 4.50 m (14.8 ft) long, 5.20 m (17.1 ft) north of the north tip of the largest treed headland on the east side of the entrance to Port Alexander, and 1.10 m (3.6 ft) above beach level and approximately 15.24 cm (6 in) above a white metal witness post.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 6 of 8 Station ID: 9451054 PUBLICATION DATE: 12/15/2020 Name: PORT ALEXANDER, BARANOF ISLAND AK NOAA Chart: 17331 Latitude: 56° 14.8' N ( 56.24670) USGS Quad: PORT ALEXANDER Longitude: 134° 38.8' W (-134.64700) T I D A L B E N C H M A R K S BENCH MARK STAMPING: 1054 H 2007 DESIGNATION: 945 1054 H MONUMENTATION: Bench Mark disk VM#: 18479 AGENCY: National Ocean Service (NOS) IDB PID: SETTING CLASSIFICATION: Rock outcrop OPUS PID: LATITUDE: 56° 14.6' N ( 56.24342) LONGITUDE: 134° 38.8' W (-134.64692) The bench mark is a disk set flush in a flat crevice of a rock protrusion, 100.9 m (331 ft) NNE of bench mark 945 1054 F, 62.04 m (203.5 ft) NE of the north tip of the largest treed headland on the east side of the entrance to Port Alexander, 59.9 m (196.5 ft) SSE of bench mark 945 1054 G, 20.30 m (66.6 ft) NNW of the north tip a 12 m (39 ft) high rocky spire which is the tallest bare headland on the east side of the entrance to Port Alexander, 15.50 m (50.9 ft) east of a 0.90 m x 0.40 m x 0.60 m high (3.0 ft x 1.3 ft x 2.0 ft) Quartzite projection on a prominent vein that is 4.50 m (14.8 ft) long, 1.00 m (3.3 ft) above beach level, and 30 cm (12 in) above a white metal witness post sign. BENCH MARK STAMPING: 945 1054 J 2014 DESIGNATION: 945 1054 J MONUMENTATION: Bench Mark disk VM#: 21194 AGENCY: National Ocean Service IDB PID: SETTING CLASSIFICATION: Bedrock outcrop OPUS PID: LATITUDE: 56° 14.7' N ( 56.24483) LONGITUDE: 134° 38.8' W (-134.64742) The bench mark is a disk set in a bedrock outcrop, 36.95 m (121.2 ft) SW of the green tsunami GPS antenna, 28.5 m (93.5 ft) W of the direct way internet/satellite antenna mast near four solar panels, 2 m (6.6 ft) S of the N face of a rock outcrop and 1.5 m (4.9 ft) above the wave cut platform.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 7 of 8 Station ID: 9451054 PUBLICATION DATE: 12/15/2020 Name: PORT ALEXANDER, BARANOF ISLAND AK NOAA Chart: 17331 Latitude: 56° 14.8' N ( 56.24670) USGS Quad: PORT ALEXANDER Longitude: 134° 38.8' W (-134.64700) T I D A L D A T U M S Tidal datums at PORT ALEXANDER, BARANOF ISLAND based on: LENGTH OF SERIES: 11 YEARS TIME PERIOD: 9/2007-8/2008, 6/2009-5/2019 TIDAL EPOCH: 1983-2001 CONTROL TIDE STATION: 9451600 SITKA, BARANOF ISLAND, SITKA SOUND Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS: HIGHEST OBSERVED WATER LEVEL (12/23/2007) = 4.552 MEAN HIGHER HIGH WATER MHHW = 3.333 MEAN HIGH WATER MHW = 3.074 MEAN TIDE LEVEL MTL = 1.757 MEAN SEA LEVEL MSL = 1.749 MEAN LOW WATER MLW = 0.440 North American Vertical Datum NAVD88 = 0.360 MEAN LOWER LOW WATER MLLW = 0.000 LOWEST OBSERVED WATER LEVEL (12/14/2008) = -1.305 North American Vertical Datum (NAVD88) Bench Mark Elevation Information In METERS above: Stamping or Designation MLLW MHW 945 1054 TIDAL 1 5.003 1.929 2 1924 4.420 1.346 1054 A 2007 5.516 2.442 1054 B 2007 3.687 0.613 1054 C 2007 3.788 0.714 1054 D 2007 9.055 5.981 1054 E 2007 5.677 2.603 1054 F 2007 4.202 1.128 1054 G 2007 4.396 1.322 1054 H 2007 5.009 1.935 945 1054 J 2014 4.419 1.345
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 8 of 8 Station ID: 9451054 PUBLICATION DATE: 12/15/2020 Name: PORT ALEXANDER, BARANOF ISLAND AK NOAA Chart: 17331 Latitude: 56° 14.8' N ( 56.24670) USGS Quad: PORT ALEXANDER Longitude: 134° 38.8' W (-134.64700) 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.