U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  1 of  4

                                                                                
Station ID: 8516299                                PUBLICATION DATE:  10/30/2003
Name:       BAYVILLE BRIDGE, OYSTER BAY                       
            NEW YORK
NOAA Chart: 12365                                  Latitude:         40ø 54.2' N
USGS Quad:  BAYVILLE                               Longitude:        73ø 33.0' W


To reach the tidal bench marks from exit 41 North on Long Island Expressway,
proceed north on Oyster Bay Road (State Highway 106) for 9.3 km (5.8 mi) to West
Main Street at Oyster Bay, then turn left and proceed west on West Main Street
for 1.3 km (0.8 mi) to West Shore Road, then veer right onto West Shore Road and
proceed north for 3.2 km (2.0 mi) to the Bayville bridge which crosses over Mill
Neck Bay.  The bench marks are along West Shore Road near the bridge.  The tide
gauge and staff were on the SE bridge fender below the center of the bridge.


                         T I D A L   B E N C H   M A R K S


                 PRIMARY BENCH MARK STAMPING:  BRIDGE NO 1 1966
                         DESIGNATION:          BRIDGE RM 1

MONUMENTATION:           Reference Mark disk                       VM#:     7080
AGENCY:                  US Coast and Geodetic Survey (USC&GS)     PID#:  AE4709
SETTING CLASSIFICATION:  Granite bulkhead of bridge


The primary bench mark is a disk set in the top of the granite retaining wall of
the Bayville bridge approach on the south end and the east side of the bridge,
5.97 m (19.6 ft) south of the SW corner of bridge light post #M-2388, 0.46 m
(1.5 ft) west of the east edge of the coping, and 0.15 m (0.5 ft) east of the
west edge of the coping.



                         BENCH MARK STAMPING:  BRIDGE 1966
                         DESIGNATION:          BRIDGE

MONUMENTATION:           Triangulation Station disk                VM#:     7079
AGENCY:                  US Coast and Geodetic Survey (USC&GS)     PID#:  KU2902
SETTING CLASSIFICATION:  Concrete monument


The bench mark is a disk set in a round concrete monument located in the grass
between the highway and the sidewalk on the east side and the south end of the
Bayville bridge, 16.92 m (55.5 ft) north of the NW corner of concrete bridge
light post #M-2387, 2.59 m (8.5 ft) west of the SW corner of concrete bridge
light post #M-2388, and 2.10 m (6.9 ft) east of the east curb face of the
highway.

U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 2 of 4 Station ID: 8516299 PUBLICATION DATE: 10/30/2003 Name: BAYVILLE BRIDGE, OYSTER BAY NEW YORK NOAA Chart: 12365 Latitude: 40ø 54.2' N USGS Quad: BAYVILLE Longitude: 73ø 33.0' W T I D A L B E N C H M A R K S BENCH MARK STAMPING: 6299 A 1990 DESIGNATION: 851 6299 A MONUMENTATION: Tidal Station disk VM#: 7081 AGENCY: National Ocean Service (NOS) PID: SETTING CLASSIFICATION: Concrete storm drain pad The bench mark is a disk set in a concrete storm drain pad located at the NW corner of the intersection of West Shore Road and The Concourse, 5.06 m (16.6 ft) west of the centerline of West Shore Road, 1.68 m (5.5 ft) north of the south edge of the storm drain pad, and 1.16 m (3.8 ft) west of the east edge of the pad.

U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 3 of 4 Station ID: 8516299 PUBLICATION DATE: 10/30/2003 Name: BAYVILLE BRIDGE, OYSTER BAY NEW YORK NOAA Chart: 12365 Latitude: 40ø 54.2' N USGS Quad: BAYVILLE Longitude: 73ø 33.0' W D A T U M S Datums at BAYVILLE BRIDGE, OYSTER BAY based on: LENGTH OF SERIES: 3 MONTHS TIME PERIOD: June 1990 - August 1990 TIDAL EPOCH: 1983-2001 CONTROL TIDE STATION: 8518490 NEW ROCHELLE Elevations of datums referred to Mean Lower Low Water (MLLW), in METERS: MEAN HIGHER HIGH WATER (MHHW) = 2.442 MEAN HIGH WATER (MHW) = 2.332 MEAN TIDE LEVEL (MTL) = 1.205 MEAN SEA LEVEL (MSL) = 1.200 MEAN LOW WATER (MLW) = 0.078 MEAN LOWER LOW WATER (MLLW) = 0.000

U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 4 of 4 Station ID: 8516299 PUBLICATION DATE: 10/30/2003 Name: BAYVILLE BRIDGE, OYSTER BAY NEW YORK NOAA Chart: 12365 Latitude: 40ø 54.2' N USGS Quad: BAYVILLE Longitude: 73ø 33.0' 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 (NAVD 88). NGVD 29 is a fixed datum adopted as a national standard geodetic reference for heights but is now considered superseded. NGVD 29 is sometimes referred to as Sea Level Datum of 1929 or as Mean Sea Level on some early issues of Geological Survey Topographic Quads. NGVD 29 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 NGVD 29 are available from the National Geodetic Survey (NGS) data base via the World Wide Web at National Geodetic Survey. NAVD 88 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. NAVD 88 replaces NGVD 29 as the national standard geodetic reference for heights. Bench mark elevations relative to NAVD 88 are available from NGS through the World Wide Web at National Geodetic Survey. NGVD 29 and NAVD 88 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 NAVD 88 elevation is shown on the Elevations of Tidal Datums Table Referred to MLLW only when two or more of the bench marks listed have NAVD 88 elevations. The NAVD 88 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, NAVD 88 bench mark elevations computed indirectly from the tidal datums elevation table may differ slightly from NAVD 88 elevations listed for each bench mark in the NGS database.