U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 5
PUBLICATION DATE: 04/05/1990
Station ID: 8542425 SUPERCEDED DATE: 04/21/2003
Name: WANNAMAKER BRIDGE, DARBY CREEK
PENNSYLVANIA
NOAA Chart: 12312 Latitude: 39° 52.6' N
USGS Quad: LANSDOWNE Longitude: 75° 18.3' W
To reach the tidal bench marks from Philadelphia International Airport, proceed
3.7 miles (6.0 km) SW on Interstate Highway 95 to State Road 420 (Wannamaker
Avenue Exit), and then 0.3 mile (0.5 km) NW on State Road 420 to Wannamaker
Bridge over Darby Creek. The bench marks are along the east side of northbound
State Road 420 to the south of the bridge. The tide gage and staff were on the
wooden bumper piles on the NE side of the bridge.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 2425 A 1976
MONUMENTATION: Survey Disk VM#: 2907
AGENCY: PID:
SETTING CLASSIFICATION: Concrete Bridge Abutment
The bench mark is set in the NW concrete abutment on the northbound lane of
Wannamaker Bridge, 29.6 feet (9.0 m) SE of the corner of the NE abutment,
17.2 feet (5.2 m) west of the centerline of the northbound lane, and 1.8 feet
(0.5 m) above grade.
BENCH MARK STAMPING: E 277 1961
MONUMENTATION: Survey Disk VM#: 2905
AGENCY: PID#: JU0767
SETTING CLASSIFICATION: Concrete Bridge Abutment
The bench mark is set in the south end of the west concrete abutment of the
State Highway 291 bridge over Darby Creek, about 200 feet (61 m) east of the
junction of Sellers Avenue and State Highway 291, 165 feet (50 m) east of power
pole #2300, 30 feet (9 m) south of the center of a traffic island in the center
of the highway, and level with the highway.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 5
PUBLICATION DATE: 04/05/1990
Station ID: 8542425 SUPERCEDED DATE: 04/21/2003
Name: WANNAMAKER BRIDGE, DARBY CREEK
PENNSYLVANIA
NOAA Chart: 12312 Latitude: 39° 52.6' N
USGS Quad: LANSDOWNE Longitude: 75° 18.3' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: U 208 1963
MONUMENTATION: Survey Disk VM#: 2906
AGENCY: PID#: JU0768
SETTING CLASSIFICATION: Concrete Retaining Wall
The bench mark is set in the west end of the north concrete retaining wall for
the Reading Railroad Bridge (8-77) over Crum Creek, 58 feet (18 m) south of the
centerline of State Highway 291, 7 feet (2 m) north of the north rail of the
northernmost tracks, 3 feet (1 m) east of the west end of the wall, and level
with the tracks.
BENCH MARK STAMPING: 2425 B 1976
MONUMENTATION: Survey Disk VM#: 2908
AGENCY: PID:
SETTING CLASSIFICATION: Unspecified Steel Rod
The bench mark is set on the east side of State Road 420 between Interstate
Highway 95 and Wannamaker Bridge, 336 feet (102 m) south of the south end of the
bridge, 49.2 feet (15.0 m) east of the centerline of the grass median of State
Road 420, 14 feet (4 m) west of the top of the creek bank, and 6.1 feet (1.9 m)
east of a steel guard rail. The bench mark is crimped to an unspeci- fied steel
rod driven 56 feet (17 m), and encased in a 4-inch PVC pipe and concrete
kickblock.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 5
PUBLICATION DATE: 04/05/1990
Station ID: 8542425 SUPERCEDED DATE: 04/21/2003
Name: WANNAMAKER BRIDGE, DARBY CREEK
PENNSYLVANIA
NOAA Chart: 12312 Latitude: 39° 52.6' N
USGS Quad: LANSDOWNE Longitude: 75° 18.3' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 2425 D 1976
MONUMENTATION: Survey Disk VM#: 2909
AGENCY: PID:
SETTING CLASSIFICATION: Concrete Footing
The bench mark is set in the concrete footing of a steel guard rail near the
intersection of State Road 420 and the south exit ramp of Interstate Highway 95,
84.3 feet (25.7 m) east of the centerline of State Road 420, 23.5 feet (7.2 m)
NE of the centerline of the exit ramp, and 7.8 feet (2.4 m) SW of a 5-foot (2 m)
high chain link fence.
BENCH MARK STAMPING: NO STAMPING 1
MONUMENTATION: Survey Disk VM#: 2910
AGENCY: PID:
SETTING CLASSIFICATION: Concrete Bridge Abutment
The bench mark is set in the SE concrete abutment on the northbound lane of
Wannamaker Bridge, 22.3 feet (6.8 m) east of the centerline of the northbound
lane, 18.6 feet (5.7 m) north of a metal witness post, and 2 feet (1 m) above
grade.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 5
PUBLICATION DATE: 04/05/1990
Station ID: 8542425 SUPERCEDED DATE: 04/21/2003
Name: WANNAMAKER BRIDGE, DARBY CREEK
PENNSYLVANIA
NOAA Chart: 12312 Latitude: 39° 52.6' N
USGS Quad: LANSDOWNE Longitude: 75° 18.3' W
T I D A L D A T U M S
Tidal datums at WANNAMAKER BRIDGE, DARBY CREEK based on:
LENGTH OF SERIES: 9 MONTHS
TIME PERIOD: FEBRUARY - NOVEMBER 1978
TIDAL EPOCH: 1960-1978
CONTROL TIDE STATION: 8545530 PHILADELPHIA
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in FEET:
HIGHEST OBSERVED WATER LEVEL (11/08/1977) = 8.01
MEAN HIGHER HIGH WATER MHHW = 6.16
MEAN HIGH WATER MHW = 5.79
MEAN TIDE LEVEL MTL = 2.99
* NATIONAL GEODETIC VERTICAL DATUM NGVD29 = 2.04
MEAN LOW WATER MLW = 0.20
MEAN LOWER LOW WATER MLLW = 0.00
LOWEST OBSERVED WATER LEVEL (03/07/1978) = -1.81
* NGVD is based on elevations published in Quad 390751, June 1967, and NOS
leveling of 1981.
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In FEET above:
Stamping or Designation MLLW MHW
2425 A 1976 19.71 13.92
E 277 1961 31.41 25.62
U 208 1963 13.35 7.56
2425 B 1976 11.32 5.53
2425 D 1976 15.65 9.86
NO STAMPING 1 19.49 13.70
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 5
PUBLICATION DATE: 04/05/1990
Station ID: 8542425 SUPERCEDED DATE: 04/21/2003
Name: WANNAMAKER BRIDGE, DARBY CREEK
PENNSYLVANIA
NOAA Chart: 12312 Latitude: 39° 52.6' N
USGS Quad: LANSDOWNE Longitude: 75° 18.3' 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.