U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Datums Page Page 1 of 5 PUBLICATION DATE: 01/17/1992 Station ID: 8510719 SUPERCEDED DATE: 04/21/2003 Name: FISHERS ISLAND, SILVER EEL COVE NEW YORK NOAA Chart: 13214 Latitude: 41° 15.4' N USGS Quad: NEW LONDON Longitude: 72° 1.9' W To reach the tidal bench marks from Fishers Island Ferry dock on Fishers Island, proceed off the ferry and turn right into the U.S. Coast Guard Fishers Island Station. The bench marks are along the harbor perimeter and out toward the airport. The tide gauge and staff were in the west corner of the harbor on the U.S. Coast Guard bulkhead. T I D A L B E N C H M A R K S PRIMARY BENCH MARK STAMPING: BM 1 1961 MONUMENTATION: Survey Disk VM#: 11245 AGENCY: PID: SETTING CLASSIFICATION: Concrete Slab The primary bench mark is set in the center of a 10 foot (3 m) square concrete slab near the intersection of the stone jetty and the shoreline, 197 feet (60 m) north of Bench Mark NO STAMPING 1, 134.3 feet (40.9 m) NW of the NE corner a of U.S. Coast Guard bulkhead at the harbor entrance, and 7.1 feet (2.2 m) south of the north corner of the concrete slab. BENCH MARK STAMPING: BM 2 1961 MONUMENTATION: Survey Disk VM#: 11246 AGENCY: PID: SETTING CLASSIFICATION: Concrete Slab The bench mark is set in a concrete slab in the center of a traffic island for ferry truck scales at the foot of the Fishers Island Ferry dock, near the ferry office building, 176 feet (54 m) NE of the northern end of School Road, 57.4 feet (17.5 m) SW of the main vehicle loading ramp, 54.5 feet (16.6 m) south of the western gate post to the U.S. Coast Guard facility, 32.0 feet (9.8 m) north of the west corner of the ferry office building, 8.4 feet (2.6 m) NW of the north curb of the truck scales, and 7.5 feet (2.3 m) NE of a manhole cover in the center of the traffic island.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 2 of 5 PUBLICATION DATE: 01/17/1992 Station ID: 8510719 SUPERCEDED DATE: 04/21/2003 Name: FISHERS ISLAND, SILVER EEL COVE NEW YORK NOAA Chart: 13214 Latitude: 41° 15.4' N USGS Quad: NEW LONDON Longitude: 72° 1.9' W T I D A L B E N C H M A R K S BENCH MARK STAMPING: NO STAMPING 1 MONUMENTATION: Monel Rivet VM#: 11247 AGENCY: PID: SETTING CLASSIFICATION: Concrete Step The bench mark is a monel rivet in the NW end of the bottom step on the front of the NW wing of the old brick U.S. Coast Guard building (formerly U.S. Post Office), 171.0 feet (52.1 m) SW of the NE corner of the U.S. Coast Guard bulkhead at the harbor entrance, 47.6 feet (14.5 m) west of a flagpole, 11.3 feet (3.4 m) east of the north corner of the NW wing, 8.0 feet (2.4 m) north of the center of the doorway to the NW wing, and 0.7 foot (0.2 m) above the ground level. BENCH MARK STAMPING: NO STAMPING 2 MONUMENTATION: Monel Rivet VM#: 11248 AGENCY: PID: SETTING CLASSIFICATION: Concrete Step The bench mark is a monel rivet set in the north end of the bottom of an old concrete step leading from Harbor Road to a steel sculpture on the east side of Silver Eel Cove, on the east side of the road leading around the harbor (Harbor Road), 142 feet (43 m) south of the intersection of Harbor and Winthrop Roads, 127 feet (39 m) NE of the NE corner of an old brick pumphouse (now a residence on the harbor's edge), 85.4 feet (26.0 m) SE of a high section of stone retaining wall on the north side of the road, 72.0 feet (21.9 m) SE of power pole #306, 11.7 feet (3.6 m) west of the steel sculpture and 7.0 feet (2.1 m) north of the south edge of the steps. NOTE: The bench mark has been designated 2 (1943)
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 3 of 5 PUBLICATION DATE: 01/17/1992 Station ID: 8510719 SUPERCEDED DATE: 04/21/2003 Name: FISHERS ISLAND, SILVER EEL COVE NEW YORK NOAA Chart: 13214 Latitude: 41° 15.4' N USGS Quad: NEW LONDON Longitude: 72° 1.9' W T I D A L B E N C H M A R K S BENCH MARK STAMPING: NO STAMPING 3 MONUMENTATION: Monel Rivet VM#: 11249 AGENCY: PID: SETTING CLASSIFICATION: Concrete Tower Foundation The bench mark is a monel rivet set in the center of a 10 foot (3 m) square concrete foundation of an old observation tower near the entrance road to the airport from Whistler Avenue, 146.2 feet (44.6 m) SE of the SE corner of a 20x20 foot (6x6 m) concrete block garage, 105.8 feet (32.2 m) NW of the NE corner of a concrete block airport building, 43.3 feet (13.2 m) west of the centerline of the entrance road to the airport, 38.5 feet (11.7 m) SW of a fire hydrant, 76.0 feet (23.2 m) west of power pole w/transformer #317 and 3 feet (1 m) above ground.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 4 of 5 PUBLICATION DATE: 01/17/1992 Station ID: 8510719 SUPERCEDED DATE: 04/21/2003 Name: FISHERS ISLAND, SILVER EEL COVE NEW YORK NOAA Chart: 13214 Latitude: 41° 15.4' N USGS Quad: NEW LONDON Longitude: 72° 1.9' W T I D A L D A T U M S Tidal datums at FISHERS ISLAND, SILVER EEL COVE based on: LENGTH OF SERIES: 6 MONTHS TIME PERIOD: MAY - OCTOBER 1989 TIDAL EPOCH: 1960-1978 CONTROL TIDE STATION: 8461490 NEW LONDON, CT Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in FEET: HIGHEST OBSERVED WATER LEVEL (10/19/1989) = 4.59 MEAN HIGHER HIGH WATER MHHW = 2.83 MEAN HIGH WATER MHW = 2.54 MEAN TIDE LEVEL MTL = 1.36 MEAN LOW WATER MLW = 0.19 MEAN LOWER LOW WATER MLLW = 0.00 LOWEST OBSERVED WATER LEVEL (11/12/1989) = -1.19 Bench Mark Elevation Information In FEET above: Stamping or Designation MLLW MHW BM 1 1961 8.40 5.86 BM 2 1961 8.35 5.81 NO STAMPING 1 8.54 6.00 NO STAMPING 2 11.80 9.26 NO STAMPING 3 22.60 20.06
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 5 of 5 PUBLICATION DATE: 01/17/1992 Station ID: 8510719 SUPERCEDED DATE: 04/21/2003 Name: FISHERS ISLAND, SILVER EEL COVE NEW YORK NOAA Chart: 13214 Latitude: 41° 15.4' N USGS Quad: NEW LONDON Longitude: 72° 1.9' W 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 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.