U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Datums Page Page 1 of 5 Station ID: 9466057 PUBLICATION DATE: 01/12/2012 Name: POPOKAMUTE, KUSKOKWIM RIVER AK NOAA Chart: 16300 Latitude: 60° 7.4' N ( 60.12328) USGS Quad: BAIRD INLET (A-2) Longitude: 162° 30.0' W (-162.50036) To reach the tidal bench marks from Bethel Alaska, proceed by charter float plane 85 km (53 mi) SSW to a small peninsula formed by the western bank of the Kuskokwim and a tidal slough that runs NNW to SSE. The bench marks are located along the west bank of the slough and start approximately 320 m (0.2 mi) NNW of the mouth of the slough. Two gauges were deployed on the west bank of the slough monitoring the water level there, and a third gauge was installed to monitor the water level of the Kuskokwim approximately 900 m (0.56 mi) to the NNE across the slough. T I D A L B E N C H M A R K S PRIMARY BENCH MARK STAMPING: 6057 A 2010 DESIGNATION: 946 6057 A MONUMENTATION: Metal Rod VM#: 19803 AGENCY: National Ocean Service (NOS) IDB PID#: SETTING CLASSIFICATION: Stainless Steel rod OPUS PID: LATITUDE: 60° 6.9' N ( 60.11486) LONGITUDE: 162° 30.1' W (-162.50214) The primary bench mark is a metal rod set in a grassy shoal near the mouth of an unnamed tidal slough, 66.50 m (218.2 ft) SSW of bench mark 946 6057 B, 48.93 m (160.5 ft) north of lone 1.4 m wide stump with growing vegetation and 15.75 m (51.7 ft) WNW of 2 m bluff edge to slough. The datum point is set 11 cm (0.36 ft) below grade, being the top of a stainless steel rod driven 10.91 m (35.8 ft) to refusal and encased in a 6-inch PVC pipe with a 7-inch diameter National Ocean Service logo cap.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 2 of 5 Station ID: 9466057 PUBLICATION DATE: 01/12/2012 Name: POPOKAMUTE, KUSKOKWIM RIVER AK NOAA Chart: 16300 Latitude: 60° 7.4' N ( 60.12328) USGS Quad: BAIRD INLET (A-2) Longitude: 162° 30.0' W (-162.50036) T I D A L B E N C H M A R K S BENCH MARK STAMPING: 6057 B 2010 DESIGNATION: 946 6057 B MONUMENTATION: Metal Rod VM#: 19804 AGENCY: National Ocean Service (NOS) IDB PID#: SETTING CLASSIFICATION: Stainless Steel rod OPUS PID: LATITUDE: 60° 6.9' N ( 60.11539) LONGITUDE: 162° 30.1' W (-162.50197) The bench mark is a metal rod set in a grassy shoal near the mouth of an unnamed tidal slough, 69.52 m (228.1 ft) SSE of bench mark 946 6057 C, 62.20 m (204.1 ft) SSE of lone 1.4 m wide stump with growing vegetation and 17.69 m (58.0 ft) west of 2 m bluff edge to slough. The datum point is set 4 cm (0.13 ft) below grade, being the top of a stainless steel rod driven 10.96 m (36.0 ft) to refusal and encased in a 6-inch PVC pipe with a 7-inch diameter National Ocean Service logo cap. BENCH MARK STAMPING: 6057 C 2010 DESIGNATION: 946 6057 C MONUMENTATION: Metal Rod VM#: 19805 AGENCY: National Ocean Service (NOS) IDB PID#: SETTING CLASSIFICATION: Stainless Steel rod OPUS PID#: BBCC54 LATITUDE: 60° 7.0' N ( 60.11594) LONGITUDE: 162° 30.2' W (-162.50256) The bench mark is a metal rod set in a grassy shoal near the mouth of an unnamed tidal slough, 66.43 m (217.9 ft) SSE of bench mark 946 6057 D, 38.60 m (126.6 ft) WSW of high water debris line, and 8.33 m (27.3 ft) WNW of a lone 1.4 m wide stump with growing vegetation. The datum point is set 10 cm (0.33 ft) below grade, being the top of a stainless steel rod driven 12.2 m (40.0 ft) to refusal and encased in a 6-inch PVC pipe with the top of a 7-inch diameter National Ocean Service logo.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 3 of 5 Station ID: 9466057 PUBLICATION DATE: 01/12/2012 Name: POPOKAMUTE, KUSKOKWIM RIVER AK NOAA Chart: 16300 Latitude: 60° 7.4' N ( 60.12328) USGS Quad: BAIRD INLET (A-2) Longitude: 162° 30.0' W (-162.50036) T I D A L B E N C H M A R K S BENCH MARK STAMPING: 6057 D 2010 DESIGNATION: 946 6057 D MONUMENTATION: Metal Rod VM#: 19806 AGENCY: National Ocean Service (NOS) IDB PID#: SETTING CLASSIFICATION: Stainless Steel rod OPUS PID: LATITUDE: 60° 6.9' N ( 60.11539) LONGITUDE: 162° 30.1' W (-162.50197) The bench mark is a metal rod set in a grassy shoal near the mouth of an unnamed tidal slough, 75.40 m (247.4 ft) NNW of lone 1.4 m wide stump with growing vegetation, 65.55 m (215.1 ft) SSE of bench mark 946 6057 E and 38.29 m (125.6 ft) WSW of high water debris line on top of 2 m bluff edge to slough. The datum point is set 15 cm (0.49 ft) below grade, being the top of a stainless steel rod driven 11.00 m (36.1 ft) to refusal and encased in a 6-inch PVC pipe with the top of a 7-inch diameter National Ocean Service logo cap. BENCH MARK STAMPING: 6057 E 2010 DESIGNATION: 9466057 E MONUMENTATION: Metal Rod VM#: 19807 AGENCY: National Ocean Service (NOS) IDB PID#: SETTING CLASSIFICATION: Stainless Steel rod OPUS PID: LATITUDE: 60° 6.0' N ( 60.10036) LONGITUDE: 162° 30.2' W (-162.50361) The bench mark is a metal rod set in a grassy shoal near the mouth of an unnamed tidal slough, 66.56 m (218.4 ft) NW of benchmark 946 6057 D, 41.05 m (134.7 ft) SSE of intersection of bluff and high water, 17.82 m (58.5 ft) SW of high water debris line on top of 2 m bluff edge to slough. The datum point is set 11 cm (0.36 ft) below grade, being the top of a stainless steel rod driven 11.03 m (36.2 ft) to refusal and encased in a 6-inch PVC pipe with a 7-inch diameter National Ocean Service logo cap.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 4 of 5 Station ID: 9466057 PUBLICATION DATE: 01/12/2012 Name: POPOKAMUTE, KUSKOKWIM RIVER AK NOAA Chart: 16300 Latitude: 60° 7.4' N ( 60.12328) USGS Quad: BAIRD INLET (A-2) Longitude: 162° 30.0' W (-162.50036) T I D A L D A T U M S Tidal datums at POPOKAMUTE, KUSKOKWIM RIVER based on: LENGTH OF SERIES: 2 MONTHS TIME PERIOD: July 2011 - August 2011 TIDAL EPOCH: 1983-2001 CONTROL TIDE STATION: Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS: MEAN HIGHER HIGH WATER MHHW = 3.359 MEAN HIGH WATER MHW = 2.718 MEAN SEA LEVEL MSL = 1.539 MEAN TIDE LEVEL MTL = 1.453 MEAN LOW WATER MLW = 0.187 MEAN LOWER LOW WATER MLLW = 0.000 North American Vertical Datum (NAVD88) Bench Mark Elevation Information In METERS above: Stamping or Designation MLLW MHW 6057 A 2010 3.855 1.137 6057 B 2010 3.975 1.257 6057 C 2010 3.875 1.157 6057 D 2010 3.893 1.175 6057 E 2010 3.987 1.269
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 5 of 5 Station ID: 9466057 PUBLICATION DATE: 01/12/2012 Name: POPOKAMUTE, KUSKOKWIM RIVER AK NOAA Chart: 16300 Latitude: 60° 7.4' N ( 60.12328) USGS Quad: BAIRD INLET (A-2) Longitude: 162° 30.0' W (-162.50036) 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.