U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Datums Page Page 1 of 5 Station ID: 8453201 PUBLICATION DATE: 07/12/2004 Name: CASTLE HILL RI NOAA Chart: 13223 Latitude: 41° 27.8' N ( 41.46330) USGS Quad: NEWPORT Longitude: 71° 21.7' W ( -71.36170) To reach the tidal bench marks from Thames Street on the waterfront in Newport, Rhode Island, proceed south and follow the roads nearest the shoreline, Wellington Avenue, Harrison Avenue, and Ridge Road to Castle Hill in Newport Neck. The bench marks are set in the rocks at the base of the cliff between the Castle Hill Inn and the Castle Hill Light, and behind the gravel beach near the parking lot. The tide gage was set on top of the cliff behind the Castle Hill Inn parking lot with the orifice and tubing extending offshore, and the tide staff was bolted to bedrock at the shoreline behind the Castle Hill Inn parking lot. T I D A L B E N C H M A R K S PRIMARY BENCH MARK STAMPING: 3201 A 1977 DESIGNATION: 845 3201 A TIDAL MONUMENTATION: Tidal Station disk VM#: 2169 AGENCY: National Ocean Survey (NOS) IDB PID#: SETTING CLASSIFICATION: Bedrock OPUS PID: LATITUDE: 41° 27.8' N ( 41.46330) LONGITUDE: 71° 21.7' W ( -71.36170) The primary bench mark is a disk set flush in bedrock at the base of the cliff behind the Castle Hill Inn parking lot, 31 m (103 ft) north (9 magnetic) of the north edge of a gravel beach, 20 m (66 ft) NNW (352 magnetic) of bench mark 3201 B 1977, 2 m (5 ft) SW from the base of the cliff, and bears NE (38 magnetic) of Castle Hill Light.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 2 of 5 Station ID: 8453201 PUBLICATION DATE: 07/12/2004 Name: CASTLE HILL RI NOAA Chart: 13223 Latitude: 41° 27.8' N ( 41.46330) USGS Quad: NEWPORT Longitude: 71° 21.7' W ( -71.36170) T I D A L B E N C H M A R K S BENCH MARK STAMPING: 3201 B 1977 DESIGNATION: 845 3201 B TIDAL MONUMENTATION: Tidal Station disk VM#: 2170 AGENCY: National Ocean Survey (NOS) IDB PID#: SETTING CLASSIFICATION: Large rock OPUS PID: LATITUDE: 41° 27.8' N ( 41.46330) LONGITUDE: 71° 21.7' W ( -71.36170) The bench mark is a disk set flush in a large rock at the base of a cliff, south of the Castle Hill Inn parking lot, 20 m (66 ft) SSE (172 magnetic) of bench mark 3201 A 1977, 19 m (62 ft) NE (6 magnetic) of bench mark 3201 C 1977, 12 m (41 ft) NNE (22 magnetic) of the north edge of a gravel beach, 3 m (10 ft) from the crevice in the northern face of the cliff and bears NE (40 magnetic) from the Castle Hill Light. BENCH MARK STAMPING: 3201 C 1977 DESIGNATION: 845 3201 C TIDAL MONUMENTATION: Tidal Station disk VM#: 2171 AGENCY: National Ocean Survey (NOS) IDB PID#: SETTING CLASSIFICATION: Rock OPUS PID: LATITUDE: 41° 27.8' N ( 41.46330) LONGITUDE: 71° 21.7' W ( -71.36170) The bench mark is a disk set flush in a rock at the base of a cliff, between the Castle Hill Light and the Castle Hill Inn parking lot, 23 m (74 ft) NE (36 magnetic) of bench mark 3201 D 1977, 19 m (62 ft) SW (242 magnetic) of bench mark 3201 B 1977, bears NE (40 magnetic) from the flagpole at the Castle Hill Light and is set on a rock outcropping in the east corner of a gravel beach.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 3 of 5 Station ID: 8453201 PUBLICATION DATE: 07/12/2004 Name: CASTLE HILL RI NOAA Chart: 13223 Latitude: 41° 27.8' N ( 41.46330) USGS Quad: NEWPORT Longitude: 71° 21.7' W ( -71.36170) T I D A L B E N C H M A R K S BENCH MARK STAMPING: 3201 D 1977 DESIGNATION: 845 3201 D TIDAL MONUMENTATION: Tidal Station disk VM#: 2172 AGENCY: National Ocean Survey (NOS) IDB PID#: SETTING CLASSIFICATION: Rock OPUS PID: LATITUDE: 41° 27.8' N ( 41.46330) LONGITUDE: 71° 21.7' W ( -71.36170) The bench mark is a disk set flush in rock at the base of a cliff between the Castle Hill Light and the Castle Hill Inn parking lot, 23 m (74 ft) SW (216 magnetic) of bench mark 3201 C 1977, 16.86 m (55.3 ft) ENE (70 magnetic) of bench mark 3201 E 1977, 12 m (40 ft) SSE (156 magnetic) of the southernmost edge of a gravel beach and is set at the vegetation line. BENCH MARK STAMPING: 3201 E 1977 DESIGNATION: 845 3201 E TIDAL MONUMENTATION: Tidal Station disk VM#: 2173 AGENCY: National Ocean Survey (NOS) IDB PID#: SETTING CLASSIFICATION: Rock OPUS PID: LATITUDE: 41° 27.8' N ( 41.46330) LONGITUDE: 71° 21.7' W ( -71.36170) The bench mark is a disk set flush in rock at the base of a cliff between the Castle Hill Light and Castle Hill Inn parking lot, 20 m (66 ft) SSW (210 magnetic) from the SW edge of a gravel beach, 16.86 m (55.3 ft) WSW (250 ) of bench mark 3201 D 1977, bears NE (43 magnetic) from the flagpole at the Castle Hill Light, and is set at the vegetation line.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 4 of 5 Station ID: 8453201 PUBLICATION DATE: 07/12/2004 Name: CASTLE HILL RI NOAA Chart: 13223 Latitude: 41° 27.8' N ( 41.46330) USGS Quad: NEWPORT Longitude: 71° 21.7' W ( -71.36170) T I D A L D A T U M S Tidal datums at CASTLE HILL based on: LENGTH OF SERIES: 3 MONTHS TIME PERIOD: August 1977 - October 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 = 1.108 MEAN HIGH WATER MHW = 1.034 MEAN TIDE LEVEL MTL = 0.539 MEAN SEA LEVEL MSL = 0.497 MEAN LOW WATER MLW = 0.044 MEAN LOWER LOW WATER MLLW = 0.000 North American Vertical Datum (NAVD88) Bench Mark Elevation Information In METERS above: Stamping or Designation MLLW MHW 3201 A 1977 3.956 2.922 3201 B 1977 4.128 3.094 3201 C 1977 3.330 2.296 3201 D 1977 5.003 3.969 3201 E 1977 6.916 5.882
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 5 of 5 Station ID: 8453201 PUBLICATION DATE: 07/12/2004 Name: CASTLE HILL RI NOAA Chart: 13223 Latitude: 41° 27.8' N ( 41.46330) USGS Quad: NEWPORT Longitude: 71° 21.7' W ( -71.36170) 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.