U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Datums Page Page 1 of 4 PUBLICATION DATE: 09/01/1982 Station ID: 8545120 SUPERCEDED DATE: 04/21/2003 Name: MARKET STREET BRIDGE, SCHUYLKILL RIVER, PHILADELPH PENNSYLVANIA NOAA Chart: 12313 Latitude: 39° 57.3' N USGS Quad: PHILADELPHIA Longitude: 75° 10.8' W To reach the tidal bench marks from City Hall in downtown Philadelphia, Pennsylvania, which is on Market Street, proceed west on Market Street for 8 blocks to the Market Street Bridge over the Schuylkill River. The bench marks are set in foot of the bridge and along railroad tracks under the east side of the bridge. The tide gage and staff were located along a bulkhead to the north of the Market Street Bridge, 74 feet (22.6 m) north of Bench Mark 5120 A 1981. T I D A L B E N C H M A R K S PRIMARY BENCH MARK STAMPING: 5120 A 1981 MONUMENTATION: Survey Disk VM#: 2941 AGENCY: PID: SETTING CLASSIFICATION: Concrete Foundation The bench mark is set flush in a 4 x 4 foot concrete slab directly next to the north side of the bridge abutment on the east side of the Schuylkill River under the Market Street Bridge at the north end of the support foundation, 35 feet (10.7 m) NW of a set of railroad tracks under the bridge, and in the SW corner 3-inches (0.1 m) from the NW face of the foundation. BENCH MARK STAMPING: 5120 B 1981 MONUMENTATION: Survey Disk VM#: 2942 AGENCY: PID: SETTING CLASSIFICATION: Concrete Foundation The bench mark is set flush in the base of the Market Street Bridge suport on the south side of the bridge, and 9 feet (2.7 m) west of the adjacent railroad tracks, and 2-inches (0.1 m) from the SW corner of the base.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 2 of 4 PUBLICATION DATE: 09/01/1982 Station ID: 8545120 SUPERCEDED DATE: 04/21/2003 Name: MARKET STREET BRIDGE, SCHUYLKILL RIVER, PHILADELPH PENNSYLVANIA NOAA Chart: 12313 Latitude: 39° 57.3' N USGS Quad: PHILADELPHIA Longitude: 75° 10.8' W T I D A L B E N C H M A R K S BENCH MARK STAMPING: 5120 C 1981 MONUMENTATION: Survey Disk VM#: 2943 AGENCY: PID: SETTING CLASSIFICATION: Concrete Platform The bench mark is set flush on a concrete platform in between the Market Street and Chestnut Street Bridges, 20 feet (6.1 m) east of the easternmost set of railroad tracks, and 7-inches (0.2 m) from the northernmost corner of a 3.5 foot (1.1 m) high concrete platform. BENCH MARK STAMPING: 5120 D 1981 MONUMENTATION: Survey Disk VM#: 2944 AGENCY: PID: SETTING CLASSIFICATION: Concrete Platform The bench mark is set flush in a 3.5 foot (1.1 m) high concrete platform in between Market Street and Chestnut Street Bridges, 30 feet (9.1 m) east of the easternmost set of railroad tracks under the Market Street Bridge, and 14 feet (4.3 m) east from the edge of the platform next to the third outward extension of brickwork on the building next to the railroad tracks. BENCH MARK STAMPING: 5120 E 1981 MONUMENTATION: Survey Disk VM#: 2945 AGENCY: PID: SETTING CLASSIFICATION: Concrete Platform The bench mark is set flush on a concrete platform base of the Chestnut Street Bridge, 225 feet (68.6 m) south of the Market Street Bridge, 17.5 feet (5.3 m) NW from the Chestnut Street Bridge support, 3 feet (0.9 m) east of the easternmost set of railroad tracks, and 5-inches (0.2 m) from the NW corner of a concrete platform base.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 3 of 4 PUBLICATION DATE: 09/01/1982 Station ID: 8545120 SUPERCEDED DATE: 04/21/2003 Name: MARKET STREET BRIDGE, SCHUYLKILL RIVER, PHILADELPH PENNSYLVANIA NOAA Chart: 12313 Latitude: 39° 57.3' N USGS Quad: PHILADELPHIA Longitude: 75° 10.8' W T I D A L D A T U M S Tidal datums at MARKET STREET BRIDGE, SCHUYLKILL RIVER, PHILADELPH based on: LENGTH OF SERIES: 183 HW & 184 LW TIME PERIOD: MAY 16 - AUGUST 18, 1981 TIDAL EPOCH: 1960-1978 CONTROL TIDE STATION: 8545530 PHILADELPHIA, PA Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in FEET: HIGHEST OBSERVED WATER LEVEL (06/04/1981) = 7.73 MEAN HIGHER HIGH WATER MHHW = 6.54 MEAN HIGH WATER MHW = 6.10 MEAN TIDE LEVEL MTL = 3.13 MEAN LOW WATER MLW = 0.16 MEAN LOWER LOW WATER MLLW = 0.00 LOWEST OBSERVED WATER LEVEL (06/27/1981) = -0.80 Bench Mark Elevation Information In FEET above: Stamping or Designation MLLW MHW 5120 A 1981 12.39 6.29 5120 B 1981 11.56 5.46 5120 C 1981 17.03 10.93 5120 D 1981 16.97 10.87 5120 E 1981 12.97 6.87
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 4 of 4 PUBLICATION DATE: 09/01/1982 Station ID: 8545120 SUPERCEDED DATE: 04/21/2003 Name: MARKET STREET BRIDGE, SCHUYLKILL RIVER, PHILADELPH PENNSYLVANIA NOAA Chart: 12313 Latitude: 39° 57.3' N USGS Quad: PHILADELPHIA Longitude: 75° 10.8' 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.