U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Datums Page Page 1 of 6 Station ID: 8464336 PUBLICATION DATE: 06/23/2003 Name: MIDDLETOWN, CONNECTICUT RIVER CT NOAA Chart: 12377 Latitude: 41° 33.6' N ( 41.56000) USGS Quad: MIDDLETOWN Longitude: 72° 38.7' W ( -72.64500) To reach the tidal bench marks from the intersection of Main and Union Streets in Middletown, proceed east on Union Street beneath the State Highway 9 over-pass to Harbor Drive, then north on Harbor Drive for 0.2 km (0.1 mi) to Harbour Park Restaurant. The bench marks are NW of Harbour Park Restaurant. The tide gage and staff were on the wharf behind the restaurant. T I D A L B E N C H M A R K S PRIMARY BENCH MARK STAMPING: 4336 E 1987 DESIGNATION: 846 4336 E MONUMENTATION: Tidal Station disk VM#: 2265 AGENCY: National Ocean Service (NOS) IDB PID#: SETTING CLASSIFICATION: Retaining wall OPUS PID#: BBDC62 LATITUDE: 41° 33.6' N ( 41.56000) LONGITUDE: 72° 38.7' W ( -72.64500) The primary bench mark is a disk set flush in the top of the south end of a retaining wall on Harbor Drive, 59 m (192 ft) WNW of the Harbour Park Restaurant entrance, 57.61 m (189.0 ft) west of a handrail along the river, 17.40 m (57.1 ft) ENE of the east guardrail on State Highway 9, and 1.40 m (4.6 ft) above ground level.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 2 of 6 Station ID: 8464336 PUBLICATION DATE: 06/23/2003 Name: MIDDLETOWN, CONNECTICUT RIVER CT NOAA Chart: 12377 Latitude: 41° 33.6' N ( 41.56000) USGS Quad: MIDDLETOWN Longitude: 72° 38.7' W ( -72.64500) T I D A L B E N C H M A R K S BENCH MARK STAMPING: 92 W 1923 54 DESIGNATION: 92 W MONUMENTATION: Survey disk VM#: 2262 AGENCY: US Geological Survey (USGS) IDB PID#: LX0580 SETTING CLASSIFICATION: Concrete steps OPUS PID: LATITUDE: 41° 34.0' N ( 41.56670) LONGITUDE: 72° 39.2' W ( -72.65330) The bench mark is a disk set flush in the first step of the west entrance on the south side of St Johns Catholic Church at Main Street and Hartford Avenue, 31.39 m (103.0 ft) west of the centerline of St Johns street, 16.46 m (54.0 ft) east of the entrance to St Johns School, 8.17 m (26.8 ft) north of the north curb of Hartford Avenue, and 0.12 m (0.4 ft) above the sidewalk.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 3 of 6 Station ID: 8464336 PUBLICATION DATE: 06/23/2003 Name: MIDDLETOWN, CONNECTICUT RIVER CT NOAA Chart: 12377 Latitude: 41° 33.6' N ( 41.56000) USGS Quad: MIDDLETOWN Longitude: 72° 38.7' W ( -72.64500) T I D A L B E N C H M A R K S BENCH MARK STAMPING: MIDDLETOWN 1935 DESIGNATION: MIDDLETOWN MONUMENTATION: Bench Mark disk VM#: 2263 AGENCY: US Coast and Geodetic Survey (USC&GS) IDB PID#: LX0583 SETTING CLASSIFICATION: Concrete steps OPUS PID: LATITUDE: 41° 33.6' N ( 41.56000) LONGITUDE: 72° 39.0' W ( -72.65000) The bench mark is a disk set flush on the first step of the Connecticut Bank & Trust near the intersection of Main and Court Streets, 24.26 m (79.6 ft) south of the SE corner of the post office, 12.68 m (41.6 ft) NW of a yellow and green fire hydrant, 7.10 m (23.3 ft) west of the west curb of Main Street, and 0.20 m (0.65 ft) above the sidewalk.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 4 of 6 Station ID: 8464336 PUBLICATION DATE: 06/23/2003 Name: MIDDLETOWN, CONNECTICUT RIVER CT NOAA Chart: 12377 Latitude: 41° 33.6' N ( 41.56000) USGS Quad: MIDDLETOWN Longitude: 72° 38.7' W ( -72.64500) T I D A L B E N C H M A R K S BENCH MARK STAMPING: Y 14 1935 DESIGNATION: Y 14 MONUMENTATION: Bench Mark disk VM#: 2264 AGENCY: US Coast and Geodetic Survey (USC&GS) IDB PID#: LX0579 SETTING CLASSIFICATION: Bridge abutment OPUS PID: LATITUDE: 41° 34.0' N ( 41.56670) LONGITUDE: 72° 39.0' W ( -72.65000) The bench mark is a disk set in the top of the NW corner of the New York, New Haven, and Hartford Railroad bridge abutment on the west side of the river, 18.99 m (62.3 ft) east of the east rail of the north/south railroad tracks, 9.78 m (32.1 ft) NE of the NE corner of a red brick building, 2.13 m (7.0 ft) north of the north rail of the east/west tracks, and 0.76 m (2.5 ft) below track level. BENCH MARK STAMPING: DESIGNATION: 846 4336 NO STAMPING 1 MONUMENTATION: Survey disk VM#: 2266 AGENCY: City of Middletown IDB PID#: SETTING CLASSIFICATION: Concrete monument OPUS PID: LATITUDE: 41° 33.6' N ( 41.56000) LONGITUDE: 72° 38.7' W ( -72.64500) The bench mark is a disk set in a concrete monument at the NW corner of Court Street and Dekoven Drive, near the SE corner of Middletown Municipal Building, 44.78 m (146.9 ft) south of a flagpole, 14.30 m (46.9 ft) north of the centerline of Court Street, 3.84 m (12.6 ft) east of the SE corner of the stone landing of the Middletown Municipal Building steps, and 0.37 m (1.2 ft) above ground level.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 5 of 6 Station ID: 8464336 PUBLICATION DATE: 06/23/2003 Name: MIDDLETOWN, CONNECTICUT RIVER CT NOAA Chart: 12377 Latitude: 41° 33.6' N ( 41.56000) USGS Quad: MIDDLETOWN Longitude: 72° 38.7' W ( -72.64500) T I D A L D A T U M S Tidal datums at MIDDLETOWN, CONNECTICUT RIVER based on: LENGTH OF SERIES: 16 MONTHS TIME PERIOD: June 1987 - September 1988 TIDAL EPOCH: 1983-2001 CONTROL TIDE STATION: 8461490 NEW LONDON, THAMES RIVER Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS: HIGHEST OBSERVED WATER LEVEL (05/02/1988) = MEAN HIGHER HIGH WATER MHHW = 0.770 MEAN HIGH WATER MHW = 0.695 MEAN SEA LEVEL MSL = 0.374 MEAN TIDE LEVEL MTL = 0.364 North American Vertical Datum NAVD88 = 0.186 MEAN LOW WATER MLW = 0.033 MEAN LOWER LOW WATER MLLW = 0.000 LOWEST OBSERVED WATER LEVEL (10/13/1988) = North American Vertical Datum (NAVD88) Bench Mark Elevation Information In METERS above: Stamping or Designation MLLW MHW 4336 E 1987 6.025 5.330 92 W 1923 54 16.410 15.715 MIDDLETOWN 1935 15.414 14.719 Y 14 1935 10.229 9.534 846 4336 NO STAMPING 1 11.329 10.634
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 6 of 6 Station ID: 8464336 PUBLICATION DATE: 06/23/2003 Name: MIDDLETOWN, CONNECTICUT RIVER CT NOAA Chart: 12377 Latitude: 41° 33.6' N ( 41.56000) USGS Quad: MIDDLETOWN Longitude: 72° 38.7' W ( -72.64500) 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.