No Maritime Boundary Points were assigned for this survey.Eight bottom samples were assigned via the PRF. Samples were obtained at all locations and returned primarily black to brown sand. Refer to the FFF submitted with the survey deliverables for results.No platforms exist for this survey.No new surveys or further investigations are recommended for this area.As described earlier in this report, the area is in the depositional zone of a major river. Migrating sandbars, shoals, and channels are common. Sandwaves are evident on the seafloor in many areas. During survey operations, currents of 2-3 knots were commonly experienced throughout the survey area. Currents were oriented north-south, funneling through the channels. Greatest current speeds were experienced on the ebb tide with the combination of river and tidal current.No overhead features exist for this survey.Aids to navigation (ATONs) exist for this survey, but were not investigated. Buoys on the east side of the survey area were observed to be in the general location shown on the chart. However, these are seasonal buoys placed by the USCG to mark the location of the channel approaching the Kuskokwim River and are removed each winter prior to river freezeup. Their position is therefore subject to change.No ferry routes or terminals exist for this survey.No new insets are recommended for this area.No present or planned construction or dredging exist within the survey limits.No submarine features exist for this survey.No charted features exist for this survey.No maintained 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.The chart comparison was performed by examining the best-scale Electronic Navigational Charts (ENCs) that intersect the survey area. The latest edition(s) available at the time of report compilation were used. The chart comparison was accomplished by overlaying the finalized BASE surface(s) with shoal-biased soundings and the final feature file (FFF) on the charts in CARIS HIPS. The general agreement between charted soundings and survey soundings was then examined and a more detailed comparison was undertaken for any shoals or other dangerous features. In areas where a large scale chart overlapped with a small scale chart, only the larger scale chart was examined. When comparing to survey data, chart scale was taken into account so that 1 mm at chart scale was considered to be the valid radius for charted soundings and features. Results are shown in the following sections. It is recommended that in all cases of disagreement this survey should supersede charted data. USCG Notice to Mariners (NM) and USCG Local Notice to Mariners (LNM) for District 17 from week 26/2019 through 34/2019 were checked and no items were found that affected the survey area. Note that ENC metadata and non-specific geographic area objects on the ENCs that overlap the survey area were not investigated.2018-08-07122019-10-08200000US3AK84M2018-08-2092019-10-161534076US2AK95MShoals or potentially hazardous features exist for this survey, but were not investigated. Shoals, either exposed or submerged at low water, are common inshore of the 3.5 m depth limit. Areas inshore of 3.5 m should be clearly marked on the charts as unsurveyed or otherwise hazardous for navigation. All previously charted shoals have shifted position and should be updated based on the results of this survey. All charted notes regarding tidal currents, tide rips, breakers, and ripples on submerged shoals should be retained. No DTONs were submitted for this survey. The CTNARE (CAUTION AREA) objects on the ENCs noting the region as a "Changeable Area" should be retained.No uncharted features exist for this survey.The FAA Wide Area Augmentation System (WAAS) was used for real-time positioning on the Q105 for the majority of the survey. These positions were superseded in processing with PPK correctors from Applanix POSPac, as described in the DAPR.The survey vessels were configured to receive RTK-level correctors via Hemisphere AtlasLink SBAS (L-band) receivers. This was utilized throughout the survey on the ASV-CW5 but only briefly at the start of operations on the Q105. However, all real-time correctors were superseded in processing with PPK correctors from Applanix POSPac. Refer to the DAPR for additional detail.Projected UTM 3The Trimble PP-RTX subscription-based correction service within POSPac was used for final positioning. Results were good overall, usually at 0.10 m or better vertically. Refer to the DAPR for additional detail.RTXNorth American Datum 1983Port Moller9463502Cape Pierce9465137Naknek9465203Kulukak Point9465265Levelock9465419Ishkowik9465993Cape MendenhallAAAAAAASW Kuskokwim BayBBBBBBBCape CorwinCCCCCCCMean Lower Low WaterAll soundings were reduced to MLLW using the ERTDM NAD83 to MLLW separation model grid file provided by NOAA using ERS methodology. Discrete tide zones were generated using project gauge data but were used for comparison purposes only. A comparison between the provided ERTDM model and a ERZT model created using the tide zones was undertaken. There is generally good agreement between the models, with project-wide agreement averaging 0.033 m with a standard deviation of 0.271 m. See the HVCR for additional information.R341KR2019_ERTDM_NAD83-MLLWERS via ERTDMAdditional information discussing the vertical or horizontal control for this survey can be found in the accompanying HVCR.2019-09-10Survey Outlines2019-09-12MMO Training Logsheet and Observation Logs2019-09-12NCEI Sound Speed Data Submission2019-09-13Coast Pilot Report2019-11-15Tides and Water Levels Package - 9465419 Levelock2019-11-15Tides and Water Levels Package - 9465993 Ishkowik2019-11-16Tides and Water Levels Package - 9463502 Port Moller2019-11-18Tides and Water Levels Package - 9465203 Naknek2019-11-19Tides and Water Levels Package - 9465137 Cape Pierce2019-11-20Tides and Water Levels Package - 9465265 Kulukak Point2019-11-23Tides and Water Levels Package - AAAAAAA Cape Mendenhall2019-11-23Tides and Water Levels Package - BBBBBBB SW Kuskokwim Bay2019-11-27Tides and Water Levels Package - CCCCCCC Cape CorwinTerraSond Charting Program Manager2019-12-15Andrew Orthmann, C.H.This report, digital data, and all other accompanying records are approved. All records are hereby respectfully submitted for final review and acceptance.The survey data meets or exceeds the requirements set forth in the 2019 NOS Hydrographic Surveys Specifications and Deliverables document as well as the Hydrographic Survey Project Instructions and Statement of Work. This data is adequate to supersede charted data in their common areas. This survey is complete and no additional work is required with the exception of deficiencies (if any) noted in this Descriptive Report.Field operations and data processing contributing to the completion of this survey were conducted under my direct supervision with frequent personal checks of progress, integrity, and adequacy.All equipment and survey methods were used as detailed in the DAPR.GPS Vertical BustsVertical busts attributable to GPS positioning error between crosslines or overlapping mainscheme are apparent periodically in the data set. These are normally less than 0.15 m, with extreme cases showing up to 0.30 m of vertical separation. However, all crosslines (except one crossline which failed due to bottom change)--including those exhibiting or crossing areas exhibiting vertical busts--pass within IHO Order 1a, and final surfaces are within allowable TVU for the depth.Image showing survey junctions.file:///M:/OPRR341KR19/Surveys/H13248/Processed/Reports/Survey/Descriptive_Report/Report/SupportFiles/H13248_Junctions.jpgNOAA's "Gridded Surface Comparison V19.4" utility was used to complete the junction comparisons. The utility differences the surfaces from the junctioning surveys and generates statistics, including the percentage of grid cells that compare to within allowable TVU for the depth. 4 m-resolution CUBE surfaces were used for all Current surveys.Agreement between the two surveys is excellent, with a mean difference of 0.03 m with a standard deviation of 0.11 m. At least 99.5% of overlapping grid cells compare within the allowable TVU for the depth.Terrasond, Ltd.2019H1324640000SImage showing an area of up to 1 m of disagreement between the 2011 (right side of image) and 2019 (left side of image) surveys. Sandwaves are readily apparent in both data sets.file:///M:/OPRR341KR19/Surveys/H13248/Processed/Reports/Survey/Descriptive_Report/Report/SupportFiles/H12328_JunctionSandwaves.jpgA 1 m surface (H12328_MB_1m_MLLW_1of1.bag) was downloaded for H12326 from NOAA NCEI and compared to the final surface for this survey. Agreement between the surveys is poor. The mean difference is 0.25 m with a standard deviation of 0.70 m. 76% of grid cells compare within allowable TVU for the depth. Differences are attributable to bottom change in this very dynamic area. Much of the area appears surprisingly stable given the 8 years separation between the two surveys. However, the most variability exists in areas where both data sets show sandwaves on the seafloor. Terrasond, Ltd.2011H1232840000SEImage showing an area of up to 1.5 m of disagreement between the 2011 (right side of image) and 2019 (left side of image) surveys. Sandwaves are readily apparent in both data sets.file:///M:/OPRR341KR19/Surveys/H13248/Processed/Reports/Survey/Descriptive_Report/Report/SupportFiles/H12326_JunctionSandwaves.jpgA 1 m surface (H12326_MB_1m_MLLW_1of1.bag) was downloaded for H12326 from NOAA NCEI and compared to the final surface for this survey. Agreement between the surveys is marginal. The mean difference is 0.24 m with a standard deviation of 0.43 m. 91% of grid cells compare within allowable TVU for the depth. Differences are attributable to bottom change in this very dynamic area. Much of the area appears surprisingly stable given the 8 years separation between the two surveys. However, the most variability exists in areas where both data sets show sandwaves on the seafloor. An example is shown below.Terrasond, Ltd.2011H1232640000NEPOSMV Dropouts (ASV-CW5)Approximately every 24 hours during survey operations the POSMV on the ASV-CW5 would drop offline. This was observed as sudden output of obviously erroneous data by the POSMV such as excessive vessel speeds, incorrect headings, and erroneous motion, followed by an automatic reinitialization of the POSMV. The issue would often repeat 1-2 additional times over a 5-10 minute period before resuming normal operations for an additional 24 hours. No definite cause was determined. When this occurred the ASV-CW5 would break offline, note the issue in the acquisition log, circle back and proceed with rerunning the affected section of line. The affected section of line was subsequently rejected in processing. Since affected data was rejected and reran there is no adverse affect on final deliverables.All equipment and survey methods were used as detailed in the DAPR.Area of crossline failure viewed in CARIS Subset mode. Dark green soundings are mainscheme collected on JD222, while light green soundings are crossline 0229-ASV-CW5-190-C2NS06400 collected 32 days earlier on JD190. Sandwave movement causing bottom change is apparent.file:///M:/OPRR341KR19/Surveys/H13248/Processed/Reports/Survey/Descriptive_Report/Report/SupportFiles/XL_Failure_Sandwaves.pngEffort was made to ensure crosslines had good temporal and geographic distribution, were angled to enable nadir-to-nadir comparisons, and that the required minimum percent of mainscheme LNM was achieved. Crosslines were conducted with both vessels to ensure there was ample overlap for inter-vessel comparisons, with each vessel crossing the other's mainscheme lines. Since the two vessels worked in close proximity and normally ran parallel lines, crosslines were often collected in sets whenever both vessels were in simultaneous operation. Crosslines were also occasionally collected while transiting across the survey area to reach a different survey priority such as bottom sample locations or infills, leading to crosslines that were diagonal to the direction of mainscheme lines. Since the area is highly changeable, reconnaissance lines that followed the main channels were usually collected first before proceeding with collection of mainscheme lines that ran perpendicular to the channels. These reconnaissance channel lines sometimes doubled as crosslines. The crossline analysis was conducted using CARIS HIPS “Line QC Report” process. Each crossline (with all associated file segments) was selected and run separately through the process, which calculated the depth difference between each accepted crossline sounding and a "QC" BASE (CUBE-type) surface’s depth layer created from the mainscheme data. The QC surface was created with the same parameters and resolution used for the final surface, with the important distinction that the QC surface did not include crosslines so as to not bias the results. Differences in depth were grouped by beam number and statistics were computed, including the percentage of soundings with differences from the QC surface falling within IHO Order 1a. When at least 95% of the sounding differences exceed IHO Order 1a, the crossline was considered to “pass,” but when less than 95% of the soundings compare within IHO Order 1, the crossline was considered to “fail.” A 5% (or less) failure rate was considered acceptable since this approach compares soundings to a surface (instead of a surface to a surface), allowing for the possibility that noisy crossline soundings that don't adversely affect the final surface could be counted as a QC failure in this process. Lines selected as crosslines and their percentage (%) of soundings passing IHO Order 1a, sorted from highest passing to lowest, are listed below. 1160-ASV-CW5-221-C_East_XL -- 100.0% pass 0881-ASV-CW5-213-C3-5_XL -- 100.0% pass 0179-ASV-CW5-189-C1NS03200 -- 100.0% pass 0230-ASV-CW5-190-C2NS06400 -- 100.0% pass 1320-ASV-CW5-223-C_XL -- 100.0% pass 1317-ASV-CW5-223-C5 -- 100.0% pass 0512-Q105-226-CXL-11 -- 99.9% pass 1387-ASV-CW5-226-C5EW00800 -- 99.9% pass 0386-Q105-213-C_XL_01 -- 99.7% pass 0511-Q105-226-CXL-10 -- 98.7% pass 0178-ASV-CW5-189-C1NS03200 -- 98.3% pass 0180-ASV-CW5-189-C1NS03200 -- 98.3% pass 1321-ASV-CW5-223-C_XL -- 97.6% pass 0229-ASV-CW5-190-C2NS06400 -- 94.2% pass Results: Agreement between the mainscheme surface and crossline soundings is overall very good, with 13 of 14 crosslines having at least 95% of crossline soundings that compare to the mainscheme surface within IHO Order 1a. One crossline (0229-ASV-CW5-190-C2NS06400) marginally failed, with 94.2% of its soundings passing QC. This line was examined in CARIS subset mode and found to be in good agreement with mainscheme overall, but vertical differences of up to 1 m are apparent along the crossline in areas exhibiting bottom change from shifting sandwaves. The largest discrepenacies are in the vicinity of 59-29-50 N, 162-20-04 W, where 32 days separate the aquisition of crossline and mainscheme data. This area is shown in the following image. Despite the single crossline failure due to bottom change, final surfaces are within allowable TVU for the depth. Refer to Separate II: Digital Data for the detailed Crossline QC reports.The NOAA-provided ERTDM model had an uncertainty of 0.13 meters. Refer to Appendix I for correspondence. The uncertainty layer of the final surface was examined in CARIS HIPS. Uncertainty falls in the range of 0.262 to 0.568 m. Most grid cells are on the lower end of the uncertainty range, approximately 0.270 m. The larger values were observed to be on sand wave features or other areas of highly variable seafloor such as steep cut banks of shoals and sandbars as well as areas exhibiting bottom change, where many soundings of different depths contribute to the depth value of the relatively large 4 m grid cell and result in a higher standard deviation of soundings contributing to the grid cell. The final surface was also analyzed in QCTools (3.1.2), which reported that greater than 99.5% of grid cells in the final surface have uncertainty within allowable TVU for the depth.Q1051.620.025ASV1.620.02500.13ERS via ERTDM2 hoursSound speed profiles or "casts" were acquired aboard the Q105 while underway with a Teledyne Oceanscience RapidCAST system, which utilized a Valeport rapidPro SVT sound speed profiler. Surface sound speed at the sonar head was monitored continuously and a new cast was collected when the surface speed varied from the previous profile's speed at the same depth by greater than 2 m/s, leading to a cast interval of approximately 2 hours. Casts were taken as deep as possible. On survey lines with significant differences in depth, the deeper portion of the line was favored to ensure that changes across the full water column were measured. The cast data was used to correct the sounding data for both vessels, using the "nearest in distance within time" (set to 4 hours) within CARIS HIPS.Sonar system quality control checks were conducted as detailed in the quality control section of the DAPR.Bottom ChangeBottom change is evident throughout this survey, especially when data was collected days to weeks apart. The survey area is a sediment deposition area at the mouth of a major river. Large tidal and riverine currents flow across the area and form transitory features such as channels, sandbars, and submerged shoal areas. Sandwaves and related signs of sediment transport are readily apparent in the MBES data. As a result, vertical and horizontal busts that exceed allowable TVU occur periodically in the dataset. These changes commonly approach 0.4 to 0.5 m, with some change observed of up to 1.5 m in sandwave areas or along submerged cut banks. No attempt was made to edit or otherwise manually choose a seafloor in areas where this occurred. Refer to the crossline section of this report for a bottom change example.Both survey vessels were outfit for MBES data collection with similar survey equipment. The ASV-CW5 was equipped with a Reson SeaBat 7125 MBES while the Q105 used a Reson SeaBat 7101 MBES. Both vessels used Applanix POSMV 320 V5 (Wavemaster II) units for attitude and position measurements. Sound speed profiles were collected using a Valeport rapidPro SVT sensor (deployed using a Teledyne Oceanscience RapidCast system) from the Q105 only.Teledyne RESONSeaBat 7125 SVMBESTeledyne RESONSeaBat 7101MBESApplanixPOS MV 320 v5Positioning and Attitude SystemTeledyne OceansciencerapidCASTSound Speed SystemValeportrapidPro SVTSound Speed SystemASV-CW5 (foreground), and Q105 (background).file:///M:/OPRR341KR19/Surveys/H13248/Processed/Reports/Survey/Descriptive_Report/Report/SupportFiles/Vessels.jpgASV-CW50.55.5Qualifier 1051.832The Qualifier 105 (Q105) is a 32 m aluminum-hull vessel owned and operated by Support Vessels of Alaska. The Q105 acquired multibeam data and provided housing and facilities for on-site data processing. The vessel was also used to collect bottom samples, deploy/recover BMPG tide gauges, conduct sound speed casts, and deploy/recover the ASV-CW5 vessel. The ASV-CW5 (C-Worker 5) is a 5.5 m aluminum-hull Autonomous Surface Vessel (ASV) owned and operated by L3-Harris ASV. The ASV was operated in an unmanned but monitored mode, collecting multibeam data in close proximity to the Q105.Refer 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.NOAA Extended Attribute Files V2019.3NOAA Extended Attributes were used for the Final Feature File (FFF) submitted with the survey deliverables.CARIS Raster Surface (CUBE)H13248_MB_4m_MLLW_FinalMBES Set Line Spacing0804NOAA_4mMB Backscatter MosaicH13248_MBAB_1m_ASV_400kHz_1of1MBES Set Line Spacing0801N/AMB Backscatter MosaicH13248_MBAB_1m_Q105_240kHz_1of1MBES Set Line Spacing0801N/AThe final depth information for this survey was submitted as a CARIS BASE surface (CSAR format) which best represented the seafloor at the time of the 2019 survey. The surface was created from fully processed data with all final corrections applied. The surface was created using NOAA CUBE parameters and resolutions by depth range in conformance with the 2019 HSSD. The surface was finalized, and designated soundings were applied where applicable. Horizontal projection was selected as UTM Zone 3 North, NAD83. A non-finalized versions of the CSAR surface is also included which does not have a depth cutoff applied. This does not have the "_Final" designation in the filename. An S-57 (.000) Final Feature File (FFF) was submitted with the survey deliverables as well. The FFF contains data not readily represented by the final surface, including bottom samples and shoreline verification results (if any). Each object is encoded with mandatory S-57 attributes and NOAA Extended Attributes (V2019.3). Georeferenced multibeam backscatter mosaics (Geotif format in NAD83 UTM Zone 3N, 1 m resolution) were also produced and are provided with the survey deliverables. One mosaic was produced for each vessel. Note that backscatter processing and mosaic generation was not a requirement and the mosaics are provided as-is. The mosaics may have flaws or holidays which could be addressed through further processing. However, they are of sufficient quality to show the relative changes in seafloor type across the survey area.All sounding systems were calibrated as detailed in the DAPR.Deviations from the Corrections to Echo Soundings section of the DAPR are itemized below. Note that in all cases final data is within specifications. Delayed Heave Exceptions The following lines could not have Delayed Heave loaded. This was usually due to a software crash or other issue causing logging to the associated POS file to cease early. Real-time heave was used instead during all processing phases including SVP correction, Compute GPS Tide, and Merge on these lines. 0219-ASV-CW5-190-C1EW01600_-_0002 0236-ASV-CW5-191-C4EW04800_-_0001 0238-ASV-CW5-191-C4EW04800_-_0001 0239-ASV-CW5-191-C4EW04800_-_0001 1158-ASV-CW5-221-C_East_XL_-_0001 1159-ASV-CW5-221-C_East_XL_-_0001 0901-ASV-CW5-213-C1EW09600_-_0001 0902-ASV-CW5-213-C1EW09600_-_0001 0903-ASV-CW5-213-C1EW09600_-_0001Image showing survey coverage.file:///M:/OPRR341KR19/Surveys/H13248/Processed/Reports/Survey/Descriptive_Report/Report/SupportFiles/H13248_Coverage.jpgThe entire survey is adequate to supersede previous data.The overall project OPR-R341-KR-19 is intended to provide contemporary surveys to update National Ocean Service (NOS) nautical charting products in the U.S. Arctic to support commerce in the region. Automatic Identification Systems (AIS) traffic patterns feeding the Hydrographic Health model, along with direct user feedback helped to define the survey area in Kuskokwim Bay, Southwest Alaska. This area is largely unsurveyed and contains mud flats, uncharted shoals, and poorly modeled tides, forcing vessel traffic between the Kuskokwim River and northern communities to take an extended southerly route to stay in safe water. Surveying these areas within Kuskokwim Bay will allow for shorter routes, increasing the safety and efficiency of vessel traffic. This work will also directly support the maritime services available to the native communities of Kwigillingok and Kongiganak. Furthermore, this project will provide support for other NOAA Hydrographic surveys and regional tidal products by installing temporary water level measuring stations in the vicinities of Cape Newenham and Nushagak Peninsula located in Bristol Bay. Survey data within the survey limits is intended to supersede all prior survey data within the project limits.Data was successfully acquired to the survey limits or the NALL, whichever was encountered first. The NALL for this survey was the 3.5 m depth limit. 3.5 m water depth was achieved at the required line spacing (400 m). Line segments were intentionally extended or run outside the assigned survey limits on the survey's northern, eastern, and southern sides to ensure good overlap with junctioning surveys there.ASV-CW50000060.4635.600Qualifier 105000009.3177.4000000069.78.6813.0002019-07-082019-07-092019-07-102019-07-312019-08-012019-08-022019-08-082019-08-092019-08-102019-08-112019-08-122019-08-142019-08-182019-08-198000143.3Image showing survey extents.file:///M:/OPRR341KR19/Surveys/H13248/Processed/Reports/Survey/Descriptive_Report/Report/SupportFiles/H13248_SurveyExtents.jpgThe project area is located in southwest Alaska near the entrance to the Kuskokwim River in a relatively remote area of the Arctic. Vessel traffic in the region largely consists of barges and other traffic that are transiting to or from Bethel (population 6,456), the hub for SW Alaska which is located up the Kuskokwim River to the north, as well as native communities in the region. The area is heavily influenced by current and sediment transport from the Kuskokwim River. As a result it is relatively shallow with shifting shoals, sandbars, and channels. Fine sand is the predominant bottom type. The area is normally not navigable during winter due to discontinuous sea ice in the bay and river ice flows from the Kuskokwim River. The area is exposed to the west and south, with limited protection from the north and east. Bathymetric data collection was carried out in July and August of 2019 under project OPR-R341-KR-19, with final processing and reporting carried out from September through December, 2019. Supporting tide data was acquired from June through October, 2019. Work was completed concurrently with other assigned areas within Kuskokwim Bay and near Nunivak Island, and done in accordance with the Hydrographic Survey Project Instructions (dated May 10th, 2019) and the NOS Hydrographic Surveys Specifications and Deliverables (HSSD), March 2019 edition.59.4229583333162.24254055659.7789722222162.695434444All waters in survey area within Sheet 3Set Line Spacing MBES at 400 m (Refer to HSSD Section 5.2.2.4 Option A)All waters in survey areaComplete 5301 LNM. Transit mileage, system calibration mileage and data which do not meet HSSD specifications shall not count towards the completion of the LNM requirement. Notify the COR/Project Manager upon nearing completion of LNM requirement. The final survey area shall be squared off and ensure the full investigation of any features within the surveyed extent.Coverage requirements were met. 5,761 linear nautical miles (LNM) was acquired project-wide, which exceeded the required minimum of 5,301 LNM. The overage of 460 LNM (about 8.7% of required LNM) was collected to compensate for any inefficiencies incidental to the execution of line collection such as excess crossline LNM, data acquired on turns in order to scout depths between lines in shallow water, or lines ran closer together than required. Splits were required periodically to disprove charted soundings shoaler than adjacent survey soundings. Splits were usually collected parallel to mainscheme lines, but on occasion were collected perpendicular to mainscheme, transecting the charted sounding location. Note that mainscheme survey lines do not extend all the way to the assigned survey extents along much of the the southern boundary. Lines there were instead collected under junctioning survey H13246, which was acquired concurrently with this survey to identical specifications. When combined, the two surveys cover the area at the required line spacing.ContractorKuskokwim River ApproachesUnited States40000Alaska3H132482019-07-082019-08-19Navigable Areameters2019Andrew OrthmannAny revisions to the Descriptive Report (DR) applied during office processing are shown in red italic text. The DR is maintained as a field unit product, therefore all information and recommendations within this report are considered preliminary unless otherwise noted. The final disposition of survey data is represented in the NOAA nautical chart products. All pertinent records for this survey are archived at the National Centers for Environmental Information (NCEI) and can be retrieved via https://www.ncei.noaa.gov/. Products created during office processing were generated in NAD83 UTM 3N, MLLW. All references to other horizontal or vertical datums in this report are applicable to the processed hydrographic data provided by the field unit.Pacific Hydrographic BranchUTC2019-05-10Multibeam Echo SounderMultibeam Echo Sounder BackscatterKuskokwim Bay, AKTerrasondKuskokwim Bay, AK & VicinityOPR-R341-KR-19