U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Datums Page Page 1 of 5 Station ID: 9448576 PUBLICATION DATE: 09/18/2015 Name: SNEEOOSH POINT, SKAGIT BAY WA NOAA Chart: 18427 Latitude: 48° 24.0' N ( 48.40000) USGS Quad: CRESCENT HARBOR Longitude: 122° 32.9' W (-122.54800) To reach the tidal bench marks from Anacortes drive east on Highway 20, turn right on Reservation Road, turn right on Sneeoosh Road, turn right on Warren Avenue, then right on the Beach Road, then left into the parking lot for Hope Island Inn. The tidal bench marks are located along the Beach Road and the gauge was located on the west (beach) side of the Inn, under the wood deck. T I D A L B E N C H M A R K S PRIMARY BENCH MARK STAMPING: LONE TREE PT SITC 20.3 FT NAVD88 DESIGNATION: 944 8576 LONE TREE MONUMENTATION: Bench Mark disk VM#: 16170 AGENCY: Swinomish Indian Tribal Community (SITC)IDB PID#: SETTING CLASSIFICATION: Concrete pavement OPUS PID: LATITUDE: 48° 24.0' N ( 48.40000) LONGITUDE: 122° 32.9' W (-122.54800) The primary bench mark is a disk set in concrete pavement at Lone Tree Point near Thousand Trails campsite on Sneeoosh Road, 13.30 m (43.6 ft) west of the centerline of a gravel road, 6.10 m (20.0 ft) north of the center of a lone conifer tree, and 5.50 m (18.0 ft) east of west edge of the Lone Tree Point.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 2 of 5 Station ID: 9448576 PUBLICATION DATE: 09/18/2015 Name: SNEEOOSH POINT, SKAGIT BAY WA NOAA Chart: 18427 Latitude: 48° 24.0' N ( 48.40000) USGS Quad: CRESCENT HARBOR Longitude: 122° 32.9' W (-122.54800) T I D A L B E N C H M A R K S BENCH MARK STAMPING: 8576 A 2000 DESIGNATION: 944 8576 A MONUMENTATION: Tidal Station disk VM#: 16171 AGENCY: National Ocean Service (NOS) IDB PID#: SETTING CLASSIFICATION: Bedrock OPUS PID: LATITUDE: 48° 24.0' N ( 48.40000) LONGITUDE: 122° 32.9' W (-122.54800) The bench mark is a disk set in bedrock on the south side of the Hope Island Inn, 12.60 m (41.3 ft) west of the SE corner of the Inn, 12.15 m (39.9 ft) east of the west edge of the concrete foundation wall where it transitions to rock wall of the Inn, 2.20 m (7.2 ft) south of the concrete foundation wall, and at apparent high water line. BENCH MARK STAMPING: 8576 B 2000 DESIGNATION: 944 8576 B MONUMENTATION: Tidal Station disk VM#: 16172 AGENCY: National Ocean Service (NOS) IDB PID#: SETTING CLASSIFICATION: Bedrock OPUS PID: LATITUDE: 48° 24.0' N ( 48.40000) LONGITUDE: 122° 32.9' W (-122.54800) The bench mark is a disk set in bedrock on the south side of the second rocky point north of the Hope Island Inn, 21.50 m (70.5 ft) north of 4 m high x 2 m wide x 7 m deep (13 ft high x 7 ft wide x 23 ft deep) cave in the bedrock beach bluff, 3.40 m (11.2 ft) NE of west end of rocky point, 2 m (7 ft) SW of a 1.30 m (4.3 ft) high vertical rock face on the point, and 1.30 m (4.3 ft) above cobble beach 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: 9448576 PUBLICATION DATE: 09/18/2015 Name: SNEEOOSH POINT, SKAGIT BAY WA NOAA Chart: 18427 Latitude: 48° 24.0' N ( 48.40000) USGS Quad: CRESCENT HARBOR Longitude: 122° 32.9' W (-122.54800) T I D A L B E N C H M A R K S BENCH MARK STAMPING: 8576 C 2000 DESIGNATION: 944 8576 C MONUMENTATION: Tidal Station disk VM#: 16173 AGENCY: National Ocean Service (NOS) IDB PID#: SETTING CLASSIFICATION: Bedrock OPUS PID: LATITUDE: 48° 24.0' N ( 48.40000) LONGITUDE: 122° 32.9' W (-122.54800) The bench mark is a disk set in bedrock at the head of the first small cove north of the Hope Island Inn, 11.90 m (39.0 ft) south of the south buttress of the concrete retaining wall, 3.40 m (11.2 ft) north of bottom concrete step leading to wood stairway up bluff, 0.50 m (1.6 ft) east of the edge of bedrock and cobble/gravel beach, and at apparent high water line. BENCH MARK STAMPING: 8576 D 2000 DESIGNATION: 944 8576 D MONUMENTATION: Tidal Station disk VM#: 16174 AGENCY: National Ocean Service (NOS) IDB PID#: SETTING CLASSIFICATION: Bedrock OPUS PID: LATITUDE: 48° 24.0' N ( 48.40000) LONGITUDE: 122° 32.9' W (-122.54800) The bench mark is a disk set in bedrock outcrop just south of first rocky point south of Lone Tree Point, 35.60 m (116.8 ft) NW of NW corner of 2.50 m (8.2 ft) high concrete retaining wall, 8.60 m (28.2 ft) SE of bottom concrete/rock step up rocky point, 1.90 m (6.2 ft) NW of prominent rocky point just south of main point, and about 1 m (3 ft) above sand/gravel beach.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 4 of 5 Station ID: 9448576 PUBLICATION DATE: 09/18/2015 Name: SNEEOOSH POINT, SKAGIT BAY WA NOAA Chart: 18427 Latitude: 48° 24.0' N ( 48.40000) USGS Quad: CRESCENT HARBOR Longitude: 122° 32.9' W (-122.54800) T I D A L D A T U M S Tidal datums at SNEEOOSH POINT, SKAGIT BAY based on: LENGTH OF SERIES: 2 MONTHS TIME PERIOD: June 2000 - July 2000 TIDAL EPOCH: 1983-2001 CONTROL TIDE STATION: 9449880 FRIDAY HARBOR, SAN JUAN CHANNEL Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS: MEAN HIGHER HIGH WATER MHHW = 3.369 MEAN HIGH WATER MHW = 3.108 MEAN SEA LEVEL MSL = 1.946 MEAN TIDE LEVEL MTL = 1.945 MEAN LOW WATER MLW = 0.781 MEAN LOWER LOW WATER MLLW = 0.000 North American Vertical Datum (NAVD88) Bench Mark Elevation Information In METERS above: Stamping or Designation MLLW MHW LONE TREE PT SITC 20.3 FT NAVD88 6.802 3.694 8576 A 2000 3.269 0.161 8576 B 2000 3.057 -0.051 8576 C 2000 3.092 -0.016 8576 D 2000 4.003 0.895
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 5 of 5 Station ID: 9448576 PUBLICATION DATE: 09/18/2015 Name: SNEEOOSH POINT, SKAGIT BAY WA NOAA Chart: 18427 Latitude: 48° 24.0' N ( 48.40000) USGS Quad: CRESCENT HARBOR Longitude: 122° 32.9' W (-122.54800) 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.