Superseded Bench Mark Sheet for 8554399, Mahon River Entrance DE

Present Epoch

Printable version

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

                                                   PUBLICATION DATE:  08/22/2000
Station ID: 8554399                                SUPERCEDED DATE:   04/21/2003
Name:       MAHON RIVER ENTRANCE, DELAWARE BAY                
            DELAWARE
NOAA Chart: 12304                                  Latitude:         39° 11.1' N
USGS Quad:  LITTLE CREEK                           Longitude:        75° 24.0' W


To reach the tidal bench marks from the Little Creek Post Office at the
intersection of State Route 9 and Road 89 in Little Creek, proceed east on Road
89 for 4.8 km (3.0 mi) to a wooden pier extending into Delaware Bay near the
Mahon River entrance.  The bench marks are along Road 89.  The tide gage and
staff were on the Delaware Storage and Pipeline Companies wooden fuel pier near
the Mahon River entrance.


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


                 PRIMARY BENCH MARK STAMPING:   
                         DESIGNATION:          855 4399 F

MONUMENTATION:           Metal Rod                                 VM#:    15886
AGENCY:                  National Ocean Service (NOS)              PID:         
SETTING CLASSIFICATION:  Stainless steel rod in sleeve


The primary bench mark is a metal rod located near the fuel pier, 34.45 m
(113.0) WNW of the west end of the Delaware Storage and Pipeline Companies fuel
pier, 1.15 m (3.8 ft) west of power pole no. BA-30T-90, which is the first power
pole south of the fuel pier, and 0.91 m (3.0 ft) east of a witness post.  The
datum point is the top of a stainless steel rod driven 18.2 m (60 ft) to
refusal, and encased in a 0.91 m (3.0 ft) sleeve and 6-inch PVC pipe with no
logo cap.



                         BENCH MARK STAMPING:  4399 C 1983
                         DESIGNATION:          855 4399 C

MONUMENTATION:           Tidal Station disk                        VM#:     2993
AGENCY:                  National Ocean Survey (NOS)               PID:         
SETTING CLASSIFICATION:  Stainless steel rod


The bench mark is a disk located SE of the Port Mahon boat launching area, 7.77
m (25.5 ft) east of the centerline of Road 89, 6.92 m (22.7 ft) NE of a utility
pole, and 0.30 m (1.0 ft) west of a witness post.  The bench mark is crimped to
a stainless steel rod driven 16.5 m (54 ft) to refusal, and encased in a 5-inch
PVC pipe and concrete kickblock.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  2 of  4

                                                   PUBLICATION DATE:  08/22/2000
Station ID: 8554399                                SUPERCEDED DATE:   04/21/2003
Name:       MAHON RIVER ENTRANCE, DELAWARE BAY                
            DELAWARE
NOAA Chart: 12304                                  Latitude:         39° 11.1' N
USGS Quad:  LITTLE CREEK                           Longitude:        75° 24.0' W


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


                         BENCH MARK STAMPING:  4399 E 1999
                         DESIGNATION:          855 4399 E

MONUMENTATION:           Tidal Station disk                        VM#:    15887
AGENCY:                  National Ocean Service (NOS)              PID#:  AS5705
SETTING CLASSIFICATION:  Concrete and steel bulkhead


The bench mark is a disk set flush in the concrete and steel bulkhead near the
fuel pier, 8.56 m (28.1 ft) NE of the west end of the Delaware Storage and
Pipeline Companies fuel pier, 1.71 m (5.6 ft ) south of the north face of the
bulkhead, and 1.49 m (4.9 ft) west of the east face of the bulkhead.



                         BENCH MARK STAMPING:   
                         DESIGNATION:          855 4399 COE

MONUMENTATION:           Survey disk                               VM#:    15888
AGENCY:                  US Army Corps of Engineers (USCOE)        PID:         
SETTING CLASSIFICATION:  Clay tile pipe and concrete


The bench mark is a disk set in concrete in the center of  a clay pipe, just
south of the Port Mahon boat launching area, 31.82 m (104.4 ft) WNW of a power
pole with transformer No. 1122, 20.61m  (67.6 ft) north of the NE corner of the
bait and tackle shop, and 0.76 m (2.5 ft) south of a witness post.



                         BENCH MARK STAMPING:   
                         DESIGNATION:          855 4399 COE 2

MONUMENTATION:           Survey disk                               VM#:    16237
AGENCY:                  US Army Corps of Engineers (USCOE)        PID:         
SETTING CLASSIFICATION:  Pavement


The bench mark is a disk set in concrete pavement near the parking lot of the
Port Mahon River boat ramp, 30.00 m (98.4 ft) SW of the east corner of the dirt
parking lot, 11 m (36 ft) NE of the centerline of the Route 89, and 10.81 m
(35.5 ft) north of a utility pole No 107.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  3 of  4

                                                   PUBLICATION DATE:  08/22/2000
Station ID: 8554399                                SUPERCEDED DATE:   04/21/2003
Name:       MAHON RIVER ENTRANCE, DELAWARE BAY                
            DELAWARE
NOAA Chart: 12304                                  Latitude:         39° 11.1' N
USGS Quad:  LITTLE CREEK                           Longitude:        75° 24.0' W


                            T I D A L   D A T U M S 


Tidal datums at MAHON RIVER ENTRANCE, DELAWARE BAY based on:

     LENGTH OF SERIES:      4 MONTHS
     TIME PERIOD:           July 1999 - October 1999
     TIDAL EPOCH:           1960-1978
     CONTROL TIDE STATION:  8557380 LEWES, FT. MILES


Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:

     MEAN HIGHER HIGH WATER                     MHHW   =  1.886
     MEAN HIGH WATER                            MHW    =  1.746
     MEAN SEA LEVEL                             MSL    =  0.925
     MEAN TIDE LEVEL                            MTL    =  0.913
     MEAN LOW WATER                             MLW    =  0.079
     MEAN LOWER LOW WATER                       MLLW   =  0.000

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MLLW        MHW

     855 4399 F                                  2.589    0.843
     4399 C 1983                                 1.799    0.053
     4399 E 1999                                 3.047    1.301
     855 4399 COE                                2.230    0.484
     855 4399 COE 2                              2.240    0.494


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

                                                   PUBLICATION DATE:  08/22/2000
Station ID: 8554399                                SUPERCEDED DATE:   04/21/2003
Name:       MAHON RIVER ENTRANCE, DELAWARE BAY                
            DELAWARE
NOAA Chart: 12304                                  Latitude:         39° 11.1' N
USGS Quad:  LITTLE CREEK                           Longitude:        75° 24.0' 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 (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.

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