OPR-P183-RA-13Shumagin Islands, AKShumagin Islands, AKNOAA Ship RAINIERH125881East of Nagai IslandAlaskaUnited States400002013Richard T. Brennan, CDR/NOAANavigable Area2013-04-162013-07-112013-08-31Multibeam Echo SounderMultibeam Echo Sounder BackscattermetersUniversal Transverse Mercator (UTM)-8Pacific Hydrographic BranchThe purpose of this survey is to provide contemporary surveys to update National Ocean Service (NOS) nautical charts. All separates are filed with the hydrographic data. Notes in red were generated during office processing. The processing branch concurs with all information and recommendations in the DR unless otherwise noted. Page numbering may be interrupted or non-sequential. All pertinent records for this survey, including the Descriptive Report, are archived at the National Geophysical Data Center (NGDC) and can be retrieved via http://www.ngdc.noaa.gov/.NOAAThe survey area is referred to as Sheet 1: "East of Nagai Island" within the Project Instructions. The area is southeast of Nagai Island and surrounds Near Island (Figure 1).55.0326777778160.18932222254.9226861111159.984052778H12588 survey limits.file:///M:/OPRP183RA13/Surveys/H12588/Report/Original/Report/SupportFiles/H12588_Survey_Limits.pngSurvey limits were acquired in accordance with the requirements in the Project Instructions and the Hydrographic Surveys Specifications and Deliverables (HSSD).The purpose of this survey is to provide contemporary surveys to update National Ocean Service (NOS) nautical charting products.The entire survey is adequate to supersede previous data.Data acquired on survey H12588 met complete multibeam coverage requirements, including the 5 soundings per node data density requirements outlined in section 5.2.2.2 of the HSSD. In order to extract some descriptive statistics of the data density achievements, the density layer of each finalized surface was queried within CARIS and then examined in Excel (Figure 3). Overall, the required data density was achieved in 99.9% of the nodes and 100.0% of the total area.H12588 data density.file:///M:/OPRP183RA13/Surveys/H12588/Report/Original/Report/SupportFiles/H12588_Data_Density.pngSummary table showing the percentage of nodes satisfying the 5 sounding density requirements, sub-divided by the appropriate depth ranges. Note: The final row has a unit of square meters, and sums the number of different resolution nodes into a common unit of area.file:///M:/OPRP183RA13/Surveys/H12588/Report/Original/Report/SupportFiles/H12588_Data_Density_stats.pngComplete multibeam echosounder (MBES) coverage was achieved within the limits of hydrography as defined in the Project Instructions with two exceptions: There are numerous areas where the sheet limits provided by HSD were not met due to areas foul with kelp (Figure 5). These areas are delineated and attributed in the Final Feature File. One gap in survey coverage that measures 60 meters by 12 meters exists along the shoreline of Nagai Island (Figure 6). This area was considered dangerous at the time of acquisition and therefore was not completed. It should be noted that the extent of this area is shoaler than 4 meters. H12588 holidays due to areas foul with kelp.file:///M:/OPRP183RA13/Surveys/H12588/Report/Original/Report/SupportFiles/H12588_Holiday_Kelp.pngH12588 gap in coverage due to dangerous conditions.file:///M:/OPRP183RA13/Surveys/H12588/Report/Original/Report/SupportFiles/H12588_Holiday_Shoal.pngData is sufficient and adequate to supersede charted data in the common area. In addition, soundings in the vicinity of this gap were not selected for charting in the chart update product.Acquired survey coverage overlaid on Chart 16540. Scale shows depths in meters.file:///M:/OPRP183RA13/Surveys/H12588/Report/Original/Report/SupportFiles/H12588_Survey_Coverage.png2801 (RA-4)0140.200000002802 (RA-5)0158.700000002803 (RA-3)0121.800000002804 (RA-6)0116.90000017.300537.60000017.303.23019020.872013-07-112013-07-122013-07-222013-08-032013-08-042013-08-122013-08-132013-08-302013-08-31Refer to the Data Acquisition and Processing Report (DAPR) for a complete description of data acquisition and processing systems, survey vessels, quality control procedures, and data processing methods. Additional information to supplement sounding and survey data, and any deviations from the DAPR are discussed in the following sections.2801283.52802283.52803283.52804283.51905190.91906190.9All data for H12588 was acquired by NOAA Ship RAINIER's survey launches 2801, 2802, 2803, and 2804 and RAINIER's skiffs 1905 and 1906. The survey launches acquired MBES depth soundings, sound velocity profiles, and bottom samples. The skiffs conducted shoreline verification.Reson7125MBESApplanixPOS-MV V4Positioning and Attitude SystemOdim Brooke Ocean (Rolls Royce Groups)MVP30Conductivity, Temperature, and Depth SensorSeabirdSBE 19Conductivity, Temperature, and Depth SensorSeabirdSBE 19PlusConductivity, Temperature, and Depth SensorResonSVP71Sound Speed SystemMultibeam crosslines were acquired using the Reson 7125 on vessel 2804 (RA-6) on DN216. The crossline percentage does not satisfy requirements stated in Section 5.2.4.3 of the HSSD, however they do cross most mainscheme survey lines and, in the opinion of the Hydrographer, are sufficient to evaluate the accuracy and reliability of surveyed soundings and positions. A 2-meter CUBE surface was created using the mainscheme lines, while a second 2-meter CUBE surface was created using only crosslines, from which a difference surface was generated at a 2-meter resolution (Figure 7). Statistics were then derived from the difference surface and are shown in Figure 8. The average difference between the depths derived from the mainscheme and crosslines was 0.03 meters (mainscheme being shoaler) with a standard deviation of 0.09 meters. H12588 crosslines.file:///M:/OPRP183RA13/Surveys/H12588/Report/Original/Report/SupportFiles/H12588_Crossline.pngH12588 crossline comparison with mainscheme lines.file:///M:/OPRP183RA13/Surveys/H12588/Report/Original/Report/SupportFiles/H12588_Crossline_Graph.pngCrossline coverage comprises only 3.2% of mainscheme coverage and does not meet the minimum requirement of 4%, but is sufficient for QC purposes.00.0452801(RA-4)30.152802(RA-5)30.152803(RA-3)30.152804(RA-6)310.15Total propagated uncertainty values for survey H12588 were derived from a combination of fixed values for equipment and vessel characteristics, as well as field assigned values for sound speed uncertainties. In addition to the usual a priori estimates of uncertainty, some real-time and post-processed uncertainty sources were also incorporated into the depth estimates of survey H12588. Real-time uncertainties from the Reson 7125 were recorded and applied in post-processing. Applanix TrueHeave files are recorded on all survey vessels, which include an estimate of the heave uncertainty, and are applied during post-processing. Uncertainty values of submitted finalized grids were calculated in CARIS using the "Greater of the Two" of uncertainty and standard deviation (scaled to 95%). To visualize the locations in which accuracy requirements were met, for each finalized surface a custom "predicted IHO compliance" layer was created, based on the difference between calculated uncertainty of the nodes and the allowable IHO uncertainty (Figure 9). To quantify the extent to which accuracy requirements were met, the preceding "predicted IHO compliance" layers were queried within CARIS and then examined in Excel (Figure 10). Overall 100.0% by node and 100.0% by area of survey H12588 met the accuracy requirements stated in the HSSD.H12588 met IHO accuracy standards for 100.0% of the survey area. file:///M:/OPRP183RA13/Surveys/H12588/Report/Original/Report/SupportFiles/H12588_IHO.pngSummary table showing the percentage of nodes satisfying the indicated IHO accuracy level, sub-divided by the appropriate depth ranges. Note: The final row has a unit of square meters, and sums of different resolution nodes into a common unit of area. file:///M:/OPRP183RA13/Surveys/H12588/Report/Original/Report/SupportFiles/H12588_IHO_stats.pngFive junction comparisons were completed for H12588 (Figure 11). Three of the five surveys (H12589, H12590, H12591) were acquired concurrently with this survey, and two surveys (H11607, H11923) were completed in 2006 by NOAA Ship RAINIER and 2008 by NOAA Ship FAIRWEATHER, respectively. H12588 junction overview.file:///M:/OPRP183RA13/Surveys/H12588/Report/Original/Report/SupportFiles/H12588_Junction_Detail.pngH12589400002013NOAA Ship RAINIERSOverlap with survey H12589 was approximately 170 meters wide along the southern boundary of H12588 (Figure 12). Depths in the junction area range from 4 to 50 meters. A difference surface analysis between CUBE depth surfaces for each survey showed H12589 to be an average of 0.12 meters deeper than H12588, with a standard deviation of 0.14 meters (Figure 13). This is well within allowable IHO Order 1 accuracy at these depths.Junction between H12588 (blue) and H12589 (green).file:///M:/OPRP183RA13/Surveys/H12588/Report/Original/Report/SupportFiles/H12588_Junctions_H12589_surface.pngDifference surface statistics between H12588 and H12589. CUBE depth layers (2m grid size). H12588 is an average of 0.12 meters shoaler.file:///M:/OPRP183RA13/Surveys/H12588/Report/Original/Report/SupportFiles/H12588_Junctions_H12589_stats.pngH12590400002013NOAA Ship RAINIEREOverlap with survey H12590 was approximately 170 meters wide along the eastern boundary of H12588 (Figure 14). Depths in the junction area range from 43 to 51 meters. A difference surface analysis between CUBE depth surfaces for each survey showed H12590 to be an average of 0.10 meters deeper than H12588, with a standard deviation of 0.15 meters (Figure 15). This is well within allowable IHO Order 1 accuracy at these depths.Junction between H12588 (blue) and H12590 (brown).file:///M:/OPRP183RA13/Surveys/H12588/Report/Original/Report/SupportFiles/H12588_Junctions_H12590_surface.pngDifference surface statistics between H12588 and H12590. CUBE depth layers (2m grid size). H12588 is an average of 0.10 meters shoaler.file:///M:/OPRP183RA13/Surveys/H12588/Report/Original/Report/SupportFiles/H12588_Junctions_H12590_stats.pngH12591400002013NOAA Ship RAINIERSEOverlap with survey H12591 was approximately 150 meters wide by 250 meters long in the southeastern boundary of H12588 (Figure 16). Depths in the junction area range from 50 to 51 meters. A difference surface analysis between CUBE depth surfaces for each survey showed H12591 to be an average of 0.14 meters shoaler than H12588, with a standard deviation of 0.14 meters (Figure 17). This is well within allowable IHO Order 1 accuracy at these depths.Junction between H12588 (blue) and H12591 (purple).file:///M:/OPRP183RA13/Surveys/H12588/Report/Original/Report/SupportFiles/H12588_Junctions_H12591_surface.pngDifference surface statistics between H12588 and H12591. CUBE depth layers (2m grid size). H12588 is an average of 0.14 meters deeper.file:///M:/OPRP183RA13/Surveys/H12588/Report/Original/Report/SupportFiles/H12588_Junctions_H12591_stats.pngH11607100002006NOAA Ship RAINIERNOverlap with survey H11607 was approximately 20 to 200 meters wide along the northern boundary of H12588 (Figure 18). Depths in the junction area range from 13 to 25 meters. A difference surface analysis between CUBE depth surfaces for each survey showed H11607 to be on average the same depth as H12588, with a standard deviation of 0.18 meters (Figure 19).Junction between H12588 (blue) and H11607 (navy blue).file:///M:/OPRP183RA13/Surveys/H12588/Report/Original/Report/SupportFiles/H12588_Junctions_H11607_surface.pngDifference surface statistics between H12588 and H11607. CUBE depth layers (1m grid size). H12588 is on average the same depth as H11607.file:///M:/OPRP183RA13/Surveys/H12588/Report/Original/Report/SupportFiles/H12588_Junctions_H11607_stats.pngH11923200002008NOAA Ship FAIRWEATHEREOverlap with survey H11923 was approximately 180 meters wide along the eastern boundary of H12588 (Figure 20). Depths in the junction area range from 22 to 43 meters. A difference surface analysis between CUBE depth surfaces for each survey showed H11923 to be an average of 0.22 meters deeper than H12588, with a standard deviation of 0.17 meters (Figure 21).Junction between H12588 (blue) and H11923 (red).file:///M:/OPRP183RA13/Surveys/H12588/Report/Original/Report/SupportFiles/H12588_Junctions_H11923_surface.pngDifference surface statistics between H12588 and H11923. CUBE depth layers (4m grid size). H12588 is an average of 0.22 meters shoaler.file:///M:/OPRP183RA13/Surveys/H12588/Report/Original/Report/SupportFiles/H12588_Junctions_H11923_stats.png4-meter BASE surfaces of H12588 and H11923 showing the area with the largest difference captured from the same perspective and exaggeration (20 times) in CARIS HIPS and SIPS 3D View. Differences likely due to noisy data from H11923.file:///M:/OPRP183RA13/Surveys/H12588/Report/Original/Report/SupportFiles/H12588_Junctions_H11923_FA_boo.pngSonar system quality control checks were conducted as detailed in the quality control section of the DAPR.None ExistThere were no conditions or deficiencies that affected equipment operational effectiveness.Sound Speed ArtifactDespite the attempts of the survey crews to spatially and temporally collect sound speed profiles, artifacts were seen within the data in the form of 'smiles' in the northern half of data collected by 2802 on DN215 (Figure 23). This artifact does not exceed the maximum allowable error as described in HSSD 5.2.3.5 “Error Budget Analysis for Depths”.H12588 sound velocity artifact (BASE surface exaggeration set to 10).file:///M:/OPRP183RA13/Surveys/H12588/Report/Original/Report/SupportFiles/H12588_SVP_Smiles.pngData is adequate and within specifications to supersede charted data in the common area.Ellipsoid-to-Tidal Surface ComparisonUsing the GPS height determined from the SBET file, data from H12588 was referenced to the ellipse and gridded. As a QC tool an ERS to MLLW difference surface was created to identify artifacts. By differencing this ellipsoidally-referenced surface (ERS) from the traditional tidally-referenced surface, one should only see the ellipsoidal slope across the length of the survey. Any deviations from this slope would therefore be the result of an error intrinsic to either the ERS or tidal processing work flow. Misprojected SBETs, current-induced dynamic draft, incorrect waterline measurements, corrupt True Heave files, or poorly-modeled water levels are all examples of artifacts that can be identified through the difference of the ERS and tidally-referenced surfaces. Upon review of this surface, vertical offsets were found in the data when referenced to the ellipse for Launch 2804 (RA-6) on DN216 between 2000 UTC and 2020 UTC and for all of DN224. These offsets at times exceeded 0.50 meters vertically when compared to surrounding data. Out of an abundance of caution, GPS heights were removed from the lines on DN216 between 2000 UTC and 2020 UTC and from all of DN224. Since no horizontal offsets were seen at MLLW or the ellipse, the rest of the correctors within the SBETs were retained (see C.3 Additional Horizontal or Vertical Control Issues). The depth gradient between the MLLW and the ERS surfaces is expected to be similar in magnitude and position as the EGM2008-WGS84 geoid-ellipsoid separation model published by the National Geospatial-Intelligence Agency (NGA). In review it was found that the two models compare well - exhibiting a signature NW-to-SE gradient of depth differences across the survey area - particularly considering the 2.5' resolution of the NGA surface and the expected differences between the geoid and MLLW (Figure 24).Difference surface between the ellipsoidally-referenced and tidally-referenced surfaces. Difference surface is overlaid on the EGM2008-WGS84 geoid-ellipsoid separation model. file:///M:/OPRP183RA13/Surveys/H12588/Report/Original/Report/SupportFiles/H12588_ERS_MLLW.pngSound speed profiles were acquired using the SBE 19 and SBE 19Plus CTDs at discrete locations within the survey area at least once every four hours, when large changes in surface sound speed were apparent, and when moving to a new area. All casts were concatenated into a master file for each vessel and applied to lines using the "Nearest in distance within time (4 hours)" selection method (Figure 25).Distribution of sound speed profiles acquired for survey H12588.file:///M:/OPRP183RA13/Surveys/H12588/Report/Original/Report/SupportFiles/H12588_SVP_casts.pngAll equipment and survey methods were used as detailed in the DAPR.All data reduction procedures conform to those detailed in the DAPR.All sounding systems were calibrated as detailed in the DAPR.Backscatter data was acquired, but not formally processed by RAINIER personnel. However, periodic spot checks were performed to ensure backscatter quality. Backscatter was logged as .7k files and submitted to NGDC, but is not included with the data submitted to the Branch.NOAA Profile V_5_3_2All data was processed using CARIS HIPS and SIPS 8.0.4.H12588_1mCUBE1065NOAA_1mComplete MBESH12588_2mCUBE2065NOAA_2mComplete MBESH12588_4mCUBE4065NOAA_4mComplete MBESH12588_1m_0to20_finalCUBE1020NOAA_1mComplete MBESH12588_2m_18to40_finalCUBE21840NOAA_2mComplete MBESH12588_4m_36to80_finalCUBE43680NOAA_4mComplete MBESH12588_4m_CombinedCUBE4065NOAA_4mComplete MBESOne designated sounding was selected in accordance with 5.2.1.2 of the HSSD to override the gridded CUBE surfaces in an area in which the model did not accurately reflect the shoalest sounding (Figure 26).H12588 designated sounding in fathoms. file:///M:/OPRP183RA13/Surveys/H12588/Report/Original/Report/SupportFiles/H12588_Designated_Sounding.pngAdditional information discussing the vertical or horizontal control for this survey can be found in the accompanying HVCR.Mean Lower Low WaterDiscrete ZoningSand Point945-9450Bird Island945-92519459450.tidFinal Approved9459251.tidFinal ApprovedH12588CORF.zdfFinal2013-09-032013-11-19The operating National Water Level Observation Network (NWLON) primary tide station in Sand Point, AK (945-9450) and subordinate tide station on Bird Island, AK (945-9251) served as control for datum determination and as a source for water level reducers for survey H12588. A complete description of the vertical and horizontal control for this survey can be found in the accompanying Horizontal and Vertical Control Report (HVCR), submitted under separate cover.Tide note is appended to this report.North American Datum of 1983 (NAD83)UTM - Zone 04 NorthSingle BaseChernaburaAK2008AC12Bird IslandNAIn conjunction with this project, a GPS base station was established by RAINIER personnel on Bird Island; the station was operational from DN192 through DN207 and from DN222 through DN245. During the times when the Bird Island base station was not operational (DN208 through DN221 and DN246 through DN254), a Plate Boundary Observatory station on Chernabura Island (ChernaburaAK2008, AC12) was used for post-processing. There were two exceptions: Data from Launch 2801 (RA-4) on DN192 and Launch 2802 (RA-5) on DN192 were collected while the Bird Island base station was operational, but data with these correctors displayed vertical offsets when referenced to the ellipse; this data was instead post-processed using the Chernabura Island base station. Vessel kinematic data was post processed with Applanix POSPac and POSGNSS software using Single Base processing methods described in the DAPR. Cold Bay, AK (289.0 kHz)Kodiak, AK (313.0 kHz)DGPS was used for primary positioning during acquisition.GPS Heights RemovedGPS heights were removed from data for Launch 2804 (RA-6) on DN216 between 2000 UTC and 2020 UTC and for Launch 2804 (RA-6) for all of DN224 due to vertical offsets found in the data when referenced to the ellipse, which at times exceeded 0.50 meters. Since there were no horizontal offsets seen at MLLW or the ellipse, the other SBET correctors were retained. 165402528300000132010-102010-10-122010-10-30A comparison was performed with Chart 16540 (1:300,000) using a CARIS sounding layer and contour layer based on the 2m surface from H12588. Both soundings and contours have been overlaid on the chart in Figure 27. All but one of the seven charted soundings compare to within one fathom (Figure 28). The area within the sheet limits of H12588 does not currently have a charted 10-fathom contour or associated blue tint along the coast of Nagai Island or Near Island, with the exception of a 6.5-fathom sounding located in the southwest corner of H12588 (Figure 29). The Hydrographer recommends updating the 10-fathom contour to better reflect the depths seen throughout this survey. It is recommended that H12588 data supersede all charted depths on Chart 16540.H12588 soundings and contours overlaid on Chart 16540 (1:300,000).file:///M:/OPRP183RA13/Surveys/H12588/Report/Original/Report/SupportFiles/H12588_Chart%20Comparison.pngCharted sounding that differs by more than one fathom within sheet limits of H12588.file:///M:/OPRP183RA13/Surveys/H12588/Report/Original/Report/SupportFiles/H12588_Chart%20Comparison_callout.pngCharted 6.5-fathom sounding located in southwest corner of H12588. The charted 10-fathom contour should be modified to cover the entire coast of Nagai Island.file:///M:/OPRP183RA13/Surveys/H12588/Report/Original/Report/SupportFiles/H12588_Chart%20Comparison_callout2.pngUS3AK50M300000172011-06-292011-06-29falseDepth Soundings: There are many differences between ENC and RNC depth sounding locations and values. It is likely that the NOAA Ship FAIRWEATHER's 2008 survey (H11923) was sourced for all RNC soundings circled in Figure 30 (black) but were not applied to the ENC. The ENC soundings that are circled in Figure 30 (blue) are likely sourced from prior lead line surveys. The Hydrographer recommends updating the ENC. Shoreline: There is a 150-meter offset to the southwest of the Near Island shoreline feature and all underwater rock features (blue) surrounding Near Island (Figure 31). Hydrographer recommendations can be found for all features within the H12588 Final Feature File and in section D.2.1 Shoreline. US3AK50M comparison to Chart 16540.file:///M:/OPRP183RA13/Surveys/H12588/Report/Original/Report/SupportFiles/H12588_Chart%20Comparison_ENC.png150-meter shift to southwest of Near Island features. file:///M:/OPRP183RA13/Surveys/H12588/Report/Original/Report/SupportFiles/H12588_Chart%20Comparison_ENC_NearIsland.pngNo AWOIS items were assigned for this survey.There was one (1) assigned maritime boundary for this survey. The assigned feature was addressed as required and recorded in the H12588 Final Feature File (see section D.2.1 Shoreline). Five maritime boundary points were assigned for this survey. Only one of the five points coincided with a feature (rock). A feature report is appended.No charted features exist for this survey.No uncharted features exist for this survey.No Danger to Navigation Reports were submitted for this survey.No shoals or potentially hazardous features exist for this survey.No channels exist for this survey. There are no designated anchorages, precautionary areas, safety fairways, traffic separation schemes, pilot boarding areas, or channel and range lines within the survey limits.Three bottom sample locations were identified in the Project Reference File (Figure 32). Acquired bottom samples are addressed, as required, with S-57 attribution and recorded in the Final Feature File accompanying this submission.H12588 bottom samples.file:///M:/OPRP183RA13/Surveys/H12588/Report/Original/Report/SupportFiles/H12588_BottomSamples.pngShoreline verification was conducted near predicted low water in accordance with the applicable sections of NOAA HSSD and FPM. There were 28 assigned features for this survey. All assigned features were addressed as required with S-57 attribution and recorded in the H12588 Final Feature File to best represent the features at chart scale. The provided shoreline from the Composite Source File (CSF) around Near Island deviated significantly from the true coastline as well as from the acquired bathymetry. It was determined that the CSF was sourced from ENC US3AK50M (1:300,000), which had sections of outdated shoreline and features. The Hydrographer downloaded the more accurate geographic cell shoreline data, which matched the hydrography and raster chart of the area. The shoreline from GC10588 is included in the Final Feature File as an 'Update' feature. The incorrect shoreline is marked as 'Delete'. The Hydrographer recommends that the ENC be updated with the correct GC shoreline. No prior survey comparisons exist for this survey.No Aids to navigation (ATONs) exist for this survey.No overhead features exist for this survey.No submarine features exist for this survey.No ferry routes or terminals exist for this survey.No platforms exist for this survey.No significant features exist for this survey.No present or planned construction or dredging exist within the survey limits.No new surveys or further investigations are recommended for this area.No new insets are recommended for this area.As Chief of Party, Field operations for this hydrographic survey were conducted under my direct supervision, with frequent personal checks of progress and adequacy. I have reviewed the attached survey data and reports.All field sheets, this Descriptive Report, and all accompanying records and data are approved. All records are forwarded for final review and processing to the Processing Branch.The survey data meets or exceeds requirements as set forth in the NOS Hydrographic Surveys and Specifications Deliverables Manual, Field Procedures Manual, Letter Instructions, and all HSD Technical Directives. These data are adequate to supersede charted data in their common areas. This survey is complete and no additional work is required with the exception of deficiencies noted in the Descriptive Report.Richard T. Brennan, CDR/NOAACommanding Officer2013-12-11Meghan E. McGovern, LT/NOAAField Operations Officer2013-12-11James B. JacobsonChief Survey Technician2013-12-11John R. Kidd, ENS/NOAASheet Manager2013-12-11