U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Datums Page Page 1 of 5 Station ID: 8453999 PUBLICATION DATE: 07/12/2004 Name: BEAVERTAIL POINT RI NOAA Chart: 13223 Latitude: 41° 27.1' N ( 41.45170) USGS Quad: NARRAGANSETT PIER Longitude: 71° 24.1' W ( -71.40170) To reach the tidal bench marks from Newport, Rhode Island, travel west across the Newport Bridge (toll) to Conanicut Island, go south on State Road 138 and the road becomes Beavertail Road, follow Beavertail Road south to Beavertail Point at the extreme southern end of the Island, at the Point take the last turnoff on the right to a dirt road, 183 m (600 ft) north of the light at the Point. On the dirt road take the first left fork and continue down to a small parking area overlooking the tide station site. The bench marks are set in rock at the base of a small cliff. The tide gage was mounted on top of the drop off and the orifice and tubing extended offshore. The tide staff was bolted to bedrock west of Bench Mark 3999 A 1977. T I D A L B E N C H M A R K S PRIMARY BENCH MARK STAMPING: 3999 A 1977 DESIGNATION: 845 3999 A TIDAL MONUMENTATION: Tidal Station disk VM#: 2195 AGENCY: National Ocean Survey (NOS) IDB PID#: SETTING CLASSIFICATION: Rock outcrop OPUS PID: LATITUDE: 41° 27.1' N ( 41.45170) LONGITUDE: 71° 24.1' W ( -71.40170) The primary bench mark is a disk set flush in concrete in a large rock outcrop NW of Beavertail Point, 9 m (30 ft) east of the shoreline, 5.64 m (18.5 ft) west of a 3 m (9 ft) high rock face, 1 m (2 ft) north of a southern drop off and bears NNW (340 magnetic) from Beavertail Light.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 2 of 5 Station ID: 8453999 PUBLICATION DATE: 07/12/2004 Name: BEAVERTAIL POINT RI NOAA Chart: 13223 Latitude: 41° 27.1' N ( 41.45170) USGS Quad: NARRAGANSETT PIER Longitude: 71° 24.1' W ( -71.40170) T I D A L B E N C H M A R K S BENCH MARK STAMPING: 3999 B 1977 DESIGNATION: 845 3999 B TIDAL MONUMENTATION: Tidal Station disk VM#: 2196 AGENCY: National Ocean Survey (NOS) IDB PID#: SETTING CLASSIFICATION: Rock outcrop OPUS PID: LATITUDE: 41° 27.1' N ( 41.45170) LONGITUDE: 71° 24.1' W ( -71.40170) The bench mark is a disk set flush in concrete in a large rock outcrop NW of Beavertail Point, 14 m (45 ft) south of a ravine leading to the beach, 12 m (41 ft) west of the vegetation line, 5 m (16 ft) east from a drop off to a small gravel beach and bears NNW (344 magnetic) of Beavertail Light. BENCH MARK STAMPING: 3999 C 1977 DESIGNATION: 845 3999 C TIDAL MONUMENTATION: Tidal Station disk VM#: 2197 AGENCY: National Ocean Survey (NOS) IDB PID#: SETTING CLASSIFICATION: Rock outcrop OPUS PID: LATITUDE: 41° 27.1' N ( 41.45170) LONGITUDE: 71° 24.1' W ( -71.40170) The bench mark is a disk set flush in concrete in a large rock outcrop NW of Beavertail Point, 15 m (50 ft) west from a dirt foot path west of a vegetation line, 2 m (6 ft) north of a drop off to the beach, 1 m (3 ft) south of a steep drop off and bears NNW (329 magnetic) of Beavertail Light.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 3 of 5 Station ID: 8453999 PUBLICATION DATE: 07/12/2004 Name: BEAVERTAIL POINT RI NOAA Chart: 13223 Latitude: 41° 27.1' N ( 41.45170) USGS Quad: NARRAGANSETT PIER Longitude: 71° 24.1' W ( -71.40170) T I D A L B E N C H M A R K S BENCH MARK STAMPING: 3999 D 1977 DESIGNATION: 845 3999 D TIDAL MONUMENTATION: Tidal Station disk VM#: 2198 AGENCY: National Ocean Survey (NOS) IDB PID#: SETTING CLASSIFICATION: Rock outcrop OPUS PID: LATITUDE: 41° 27.1' N ( 41.45170) LONGITUDE: 71° 24.1' W ( -71.40170) The bench mark is a disk set flush in concrete in a large rock outcrop NW of Beavertail Point, 14 m (45 ft) east from the western shoreline, 11 m (36 ft) west of the vegetation line, 5 m (15 ft) north of a steep drop off to the beach, 2 m (8 ft) south from a 1 m (2 ft) drop off, and bears NNW (341 magnetic) of Beavertail Light. BENCH MARK STAMPING: 3999 E 1977 DESIGNATION: 845 3999 E TIDAL MONUMENTATION: Tidal Station disk VM#: 2199 AGENCY: National Ocean Survey (NOS) IDB PID#: SETTING CLASSIFICATION: Rock outcrop OPUS PID: LATITUDE: 41° 27.1' N ( 41.45170) LONGITUDE: 71° 24.1' W ( -71.40170) The bench mark is a disk set flush in concrete in a large rock outcrop NW of Beavertail Point, 10 m (32 ft) west of the drop off to the beach, 9 m (29 ft) south of a rock ravine, 6 m (21 ft) west of a foot path at the edge of the vegetation line, and bears NNW (343 magnetic) from Beavertail Light.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 4 of 5 Station ID: 8453999 PUBLICATION DATE: 07/12/2004 Name: BEAVERTAIL POINT RI NOAA Chart: 13223 Latitude: 41° 27.1' N ( 41.45170) USGS Quad: NARRAGANSETT PIER Longitude: 71° 24.1' W ( -71.40170) T I D A L D A T U M S Tidal datums at BEAVERTAIL POINT based on: LENGTH OF SERIES: 2 MONTHS TIME PERIOD: August 1977 - September 1977 TIDAL EPOCH: 1983-2001 CONTROL TIDE STATION: 8452660 NEWPORT, NARRAGANSETT BAY Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS: MEAN HIGHER HIGH WATER MHHW = 1.155 MEAN HIGH WATER MHW = 1.075 MEAN TIDE LEVEL MTL = 0.566 MEAN LOW WATER MLW = 0.057 MEAN LOWER LOW WATER MLLW = 0.000 North American Vertical Datum (NAVD88) Bench Mark Elevation Information In METERS above: Stamping or Designation MLLW MHW 3999 A 1977 2.744 1.669 3999 B 1977 3.762 2.687 3999 C 1977 6.237 5.162 3999 D 1977 6.004 4.929 3999 E 1977 4.303 3.228
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 5 of 5 Station ID: 8453999 PUBLICATION DATE: 07/12/2004 Name: BEAVERTAIL POINT RI NOAA Chart: 13223 Latitude: 41° 27.1' N ( 41.45170) USGS Quad: NARRAGANSETT PIER Longitude: 71° 24.1' W ( -71.40170) 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.