NOAA Web Site Link Tides and Currents Home Page Transparent placeholder image

Bench Mark Sheet for 9450623, Big Salt Lake AK

Superseded Epoch

Large map location marker Station Location
Small red map location marker Published bench mark
Small blue map location marker Unpublished bench mark

Bench mark positions only appear on the map if their coordinates in the CO-OPS database are at the precision of degrees/minutes/seconds/and tenths of seconds. If the coordinates are less precise, the mark will not appear.

Printable version

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
Datums Page                                                        Page  1 of  5

                                                                                
Station ID: 9450623                         PUBLICATION DATE:  07/31/2014
Name:       BIG SALT LAKE, ALBENO BAY                         
            AK
NOAA Chart: 17407                           Latitude:   55° 36.0' N (  55.60000)
USGS Quad:  PETERSBURG                      Longitude: 132° 57.0' W (-132.95000)


To reach the bench marks from Sitka, AK via boat, proceed SSW through Sitka
Sound for 25.0 km (13.5 NM) to Biorka Island, then turn SE and proceed 100 km
(54 NM) to Cape Ommaney, turn ESE and proceed 44.4 km (24.0 NM) through Cape
Decision to Warren Channel, turn SSE and proceed through Warren Channel for 27.8
km (15.0 NM) to Cape Lynch, turn SE and proceed 15.0 kn (8.1 NM) through Bocas
de Finas to Pt. Disconocida, then turn SE and proceed 16.0 km (9.34 NM) accross
Gulf of Esquibel, proceed SE 5.00 km (3.11 NM) through San Christoval Channel to
San christoval Rock, turn ENE and proceed 10.5 km (6.5 NM) through Shinuku
Inlet, proceed 2.90 kn (1.61 NM) through northern tidal entrance of Big Salt
Lake, turn ESE and proceed 4.50 km (2.80 NM) through small islands into Big Salt
Lake, turn NE and proceed 1.87 km (1.16 NM) further into the lake. The bench
marks are located close to the treeline on the western shore approximately half
way up the first NE leg of Big Salt Lake.  The tide staff was located along the
shore, approximately 250.0 m (820.0 ft) south of a small isthmus along the
eastern shore, and the gauge and benchmarks were installed in the vicinity.


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


                 PRIMARY BENCH MARK STAMPING:  0623 A 2008
                         DESIGNATION:          945 0623 A

MONUMENTATION:           Tidal Station disk                    VM#:        18690
AGENCY:                  National Ocean Service (NOS)          IDB PID#:        
SETTING CLASSIFICATION:  Bedrock                               OPUS PID:        
LATITUDE:   55° 36.1' N (  55.60182)          LONGITUDE: 133°  1.7' W (-133.02840)


The bench mark is a disk set in bedrock 1.5 km (0.9 nm) bearing 256 degrees T
(236 degrees m) from a small cove on the other side of Big Salt Lake, 90 km (295
nm) bearing 185 degrees T (205 degrees M) from rocky outcropping at the bend in
the northern shoreline, 0.40 km (0.25 nm) bearing 040 degrees T (020 degrees M)
from the southern point of the shoreline, 1.00 m (3.3 ft) from the treeline, and
1.50 m (4.9 ft) above the apparent high water line.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  2 of  5

                                                                                
Station ID: 9450623                         PUBLICATION DATE:  07/31/2014
Name:       BIG SALT LAKE, ALBENO BAY                         
            AK
NOAA Chart: 17407                           Latitude:   55° 36.0' N (  55.60000)
USGS Quad:  PETERSBURG                      Longitude: 132° 57.0' W (-132.95000)


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


                         BENCH MARK STAMPING:  0623 B 2008
                         DESIGNATION:          945 0623 B

MONUMENTATION:           Tidal Station disk                    VM#:        18697
AGENCY:                  National Ocean Service (NOS)          IDB PID#:        
SETTING CLASSIFICATION:  Rock outcrop                          OPUS PID:        
LATITUDE:   55° 37.1' N (  55.61864)          LONGITUDE: 133°  1.7' W (-133.02840)


The bench mark is a disk set flush in a 1 m x 1.50 m (3 ft x 5 ft) outcroping of
bedrock, 1.5 km (0.93 nm) bearing 258  T (238  M) from small cove on other side
of Big Salt Lake, 224 m (735 ft) bearing 183  T (163  M) from SW end of isthmus
to north, 25 m (82 ft) bearing 000  T (340  M) from benchmark 945 0623 A,  4 m
(13 ft) from the treeline, and 1.00 m (3.28 ft) above the apparent high water
line.



                         BENCH MARK STAMPING:  0623 C 2008
                         DESIGNATION:          945 0623 C

MONUMENTATION:           Tidal Station disk                    VM#:        18698
AGENCY:                  National Ocean Service (NOS)          IDB PID#:        
SETTING CLASSIFICATION:  Rock outcrop                          OPUS PID:        
LATITUDE:   55° 37.1' N (  55.61906)          LONGITUDE: 133°  1.7' W (-133.02808)


The bench mark is a disk set flush in a rocky outcropping at waters edge 1.50 km
(0.93 nm) bearing 260  T (240  M) from small cove on other side of Big Salt
Lake, 180.0 m (590.4 ft) bearing 182  T (162  M) from SW end of isthmus to
north, 50.00 m (164.00 ft) bearing 026  T (006  M) from benchmark 945 0623 B,
20.00 m (65.60 ft) east of treeline, and 0.85 m (2.79 ft) above high water.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  3 of  5

                                                                                
Station ID: 9450623                         PUBLICATION DATE:  07/31/2014
Name:       BIG SALT LAKE, ALBENO BAY                         
            AK
NOAA Chart: 17407                           Latitude:   55° 36.0' N (  55.60000)
USGS Quad:  PETERSBURG                      Longitude: 132° 57.0' W (-132.95000)


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


                         BENCH MARK STAMPING:  0623 D 2008
                         DESIGNATION:          945 0623 D

MONUMENTATION:           Tidal Station disk                    VM#:        18699
AGENCY:                                                        IDB PID#:        
SETTING CLASSIFICATION:  Rock outcrop                          OPUS PID:        
LATITUDE:   55° 37.2' N (  55.61952)          LONGITUDE: 133°  1.7' W (-133.02887)


The bench mark is a disk set flush in a rocky outcropping 1.60 km (0.99 nm)
bearing 262  T (242  M) from small cove on other side of Big Salt Lake, 130.0 m
(426.4 ft) bearing 202  T (182  M) from SW end of isthmus to north,  75 m (246
ft) bearing 315  T (295  M) from benchmark 945 0623 C, 5 m (16 ft) east of
treeline, and 1.05 m (3.44 ft) above the apparent high water line.



                         BENCH MARK STAMPING:  0623 E 2008
                         DESIGNATION:          945 0623 E

MONUMENTATION:           Tidal Station disk                    VM#:        18700
AGENCY:                                                        IDB PID#:        
SETTING CLASSIFICATION:  Rock                                  OPUS PID:        
LATITUDE:   55° 37.2' N (  55.61982)          LONGITUDE: 133°  1.7' W (-133.02881)


The bench mark is a disk set flush in a 1 m x 1 m (3 ft x 3 ft) rock 1.60 km
(0.99 nm) bearing 263  T (243  M) from small cove on east side of Big Salt Lake,
100 m (328 ft) bearing 207  T (187  M) from SE end of isthmus to north,  35.00 m
(114.8 ft) bearing 010  T (350  M) from benchmark 945 0623 D,  and 25 m (82 ft)
east of treeline and residing offshore at high water.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  4 of  5

                                                                                
Station ID: 9450623                         PUBLICATION DATE:  07/31/2014
Name:       BIG SALT LAKE, ALBENO BAY                         
            AK
NOAA Chart: 17407                           Latitude:   55° 36.0' N (  55.60000)
USGS Quad:  PETERSBURG                      Longitude: 132° 57.0' W (-132.95000)


                            T I D A L   D A T U M S 


Tidal datums at BIG SALT LAKE, ALBENO BAY based on:

     LENGTH OF SERIES:      30 DAYS
     TIME PERIOD:           May 17, 2008 - June 15, 2008
     TIDAL EPOCH:           1983-2001
     CONTROL TIDE STATION:  9451600 SITKA, BARONOF ISLAND, SITKA SOUND


Elevations of tidal datums referred to Mean High Water (MHW), in METERS:

     MEAN HIGHER HIGH WATER                     MHHW   =  0.220
     MEAN HIGH WATER                            MHW    =  0.000

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                                MHW

     0623 A 2008                                          0.751
     0623 B 2008                                          0.206
     0623 C 2008                                          0.097
     0623 D 2008                                          0.284
     0623 E 2008                                         -0.244


                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  5 of  5

                                                                                
Station ID: 9450623                         PUBLICATION DATE:  07/31/2014
Name:       BIG SALT LAKE, ALBENO BAY                         
            AK
NOAA Chart: 17407                           Latitude:   55° 36.0' N (  55.60000)
USGS Quad:  PETERSBURG                      Longitude: 132° 57.0' W (-132.95000)


                             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.

Return to Top
Products available at 9450623 Big Salt Lake, AK

Revised: 10/15/2013
NOAA / National Ocean Service
Web site owner: Center for Operational Oceanographic Products and Services