U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Datums Page Page 1 of 5 Station ID: 9455128 PUBLICATION DATE: 04/21/2003 Name: BEAR COVE AK NOAA Chart: 16682 Latitude: 59° 48.1' N ( 59.80170) USGS Quad: BLYING SOUND (D-7) Longitude: 149° 36.9' W (-149.61500) To reach the tidal benchmarks from Seward via boat, proceed 15 km (8 nm) SSE along Resurrection Bay to Calisto Head, then 32.4 km (17.6 nm) south along Resurrection Bay to Aialik Cape, then 8.5 km (4.6 nm) NNW along Aialik Bay to the southwestern point of Three Hole Bay, then 5.5 km (3.0 nm) north along Aialik Bay to the mouth of Bear Cove, then 2.8 km (1.5 nm) NE to the tide station. The bench marks are located along the shoreline. The tide station was located on the hillside in the trees above bench mark 5128 D 2000. T I D A L B E N C H M A R K S PRIMARY BENCH MARK STAMPING: 9455128 D 2000 DESIGNATION: 945 5128 D MONUMENTATION: Tidal Station disk VM#: 16367 AGENCY: National Ocean Service (NOS) IDB PID#: SETTING CLASSIFICATION: Rock outcrop OPUS PID: LATITUDE: 59° 48.1' N ( 59.80200) LONGITUDE: 149° 36.9' W (-149.61500) The primary benchmark is a disk set in a rock outcrop where the rocky shore takes an abrupt turn from E-W to N-S orientation in this vicinity, 19 m (62 ft) SE of benchmark 9455128 C 2000, 9 m (30 ft) west of benchmark 9455128 E 2000, 3 m (10 ft) from vegetation line, and 2 m (7 ft) below vegetation line.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 2 of 5 Station ID: 9455128 PUBLICATION DATE: 04/21/2003 Name: BEAR COVE AK NOAA Chart: 16682 Latitude: 59° 48.1' N ( 59.80170) USGS Quad: BLYING SOUND (D-7) Longitude: 149° 36.9' W (-149.61500) T I D A L B E N C H M A R K S BENCH MARK STAMPING: 9455128 A 2000 DESIGNATION: 945 5128 A MONUMENTATION: Tidal Station disk VM#: 16364 AGENCY: National Ocean Service (NOS) IDB PID#: SETTING CLASSIFICATION: Rock outcrop OPUS PID: LATITUDE: 59° 48.1' N ( 59.80200) LONGITUDE: 149° 36.9' W (-149.61500) The benchmark is a disk set in a sloping rock outcrop projecting 3 m (10 ft) NNW from the shore, 15 m (49 ft) north of benchmark 9455128 C 2000, 6 m (19 ft) north of benchmark 9455128 B 2000, 2 m (8 ft) from the vegetation line, and 2 m (5 ft) below the vegetation line. BENCH MARK STAMPING: 9455128 B 2000 DESIGNATION: 945 5128 B MONUMENTATION: Tidal Station disk VM#: 16365 AGENCY: National Ocean Survey (NOS) IDB PID#: SETTING CLASSIFICATION: Rock outcrop OPUS PID: LATITUDE: 59° 48.1' N ( 59.80200) LONGITUDE: 149° 36.9' W (-149.61500) The benchmark is a disk set in a shoulder of rock outcrop, 9 m (29 ft) north of benchmark 9455128 C 2000, 6 m (19 ft) south of benchmark 9455128 A 2000, 1 m (4 ft) from the vegetation line, 1 m (3 ft) north of a large overhanging spruce tree, and 1 m (4 ft) below the vegatation line.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 3 of 5 Station ID: 9455128 PUBLICATION DATE: 04/21/2003 Name: BEAR COVE AK NOAA Chart: 16682 Latitude: 59° 48.1' N ( 59.80170) USGS Quad: BLYING SOUND (D-7) Longitude: 149° 36.9' W (-149.61500) T I D A L B E N C H M A R K S BENCH MARK STAMPING: 9455128 C 2000 DESIGNATION: 945 5128 C MONUMENTATION: Tidal Station disk VM#: 16366 AGENCY: National Ocean Service (NOS) IDB PID#: SETTING CLASSIFICATION: Rock outcrop OPUS PID: LATITUDE: 59° 48.1' N ( 59.80200) LONGITUDE: 149° 36.9' W (-149.61500) The benchmark is a disk set in a rock outcropping, 19 m (62 ft) NW of benchmark 9455128 D 2000, 15 m (49 ft) south of benchmark 9455128 A 2000, 9 m (29 ft) south of benchmark 9455128 B 2000, 2 m (8 ft) from vegetation line, and 2 m (6 ft) below vegatation line. BENCH MARK STAMPING: 9455128 E 2000 DESIGNATION: 945 5128 E MONUMENTATION: Tidal Station disk VM#: 16368 AGENCY: National Ocean Service (NOS) IDB PID#: SETTING CLASSIFICATION: Rock outcrop OPUS PID: LATITUDE: 59° 48.1' N ( 59.80200) LONGITUDE: 149° 36.8' W (-149.61300) The benchmark is a disk set in a 1 m (2 ft) wide shoulder of a rock outcrop which drops off nearly vertical a few feet south of the mark, 9 m (30 ft) east of benchmark 9455128 D 2000, 2 m (5 ft) from vegetation line, and 3 m (10 ft) below vegetation line.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 4 of 5 Station ID: 9455128 PUBLICATION DATE: 04/21/2003 Name: BEAR COVE AK NOAA Chart: 16682 Latitude: 59° 48.1' N ( 59.80170) USGS Quad: BLYING SOUND (D-7) Longitude: 149° 36.9' W (-149.61500) T I D A L D A T U M S Tidal datums at BEAR COVE based on: LENGTH OF SERIES: 4 Months TIME PERIOD: July 2000 - October 2000 TIDAL EPOCH: 1983-2001 CONTROL TIDE STATION: 9455090 SEWARD, RESURRECTION BAY Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS: MEAN HIGHER HIGH WATER MHHW = 3.223 MEAN HIGH WATER MHW = 2.950 MEAN SEA LEVEL MSL = 1.683 MEAN TIDE LEVEL MTL = 1.680 MEAN LOW WATER MLW = 0.409 MEAN LOWER LOW WATER MLLW = 0.000 North American Vertical Datum (NAVD88) Bench Mark Elevation Information In METERS above: Stamping or Designation MLLW MHW 9455128 D 2000 3.496 0.546 9455128 A 2000 3.656 0.706 9455128 B 2000 3.899 0.949 9455128 C 2000 3.387 0.437 9455128 E 2000 3.500 0.550
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 5 of 5 Station ID: 9455128 PUBLICATION DATE: 04/21/2003 Name: BEAR COVE AK NOAA Chart: 16682 Latitude: 59° 48.1' N ( 59.80170) USGS Quad: BLYING SOUND (D-7) Longitude: 149° 36.9' W (-149.61500) 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.