Single-beam bathymetry data collected in the Cache Slough Complex, Sacramento-San Joaquin Delta, California, during USGS field activities 2017-649-FA and 2018-684-FA

Frequently anticipated questions:

• What does this data set describe?
  1. How might this data set be cited?
  2. What geographic area does the data set cover?
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
  5. What is the general form of this data set?
  6. How does the data set represent geographic features?
  7. How does the data set describe geographic features?
• Who produced the data set?
  1. Who are the originators of the data set?
  2. Who also contributed to the data set?
  3. To whom should users address questions about the data?
• Why was the data set created?
• How was the data set created?
  1. From what previous works were the data drawn?
  2. How were the data generated, processed, and modified?
  3. What similar or related data should the user be aware of?
• How reliable are the data; what problems remain in the data set?
  1. How well have the observations been checked?
  2. How accurate are the geographic locations?
  3. How accurate are the heights or depths?
  4. Where are the gaps in the data? What is missing?
  5. How consistent are the relationships among the data, including topology?
• How can someone get a copy of the data set?
  1. Are there legal restrictions on access or use of the data?
  2. Who distributes the data?
  3. What's the catalog number I need to order this data set?
  4. What legal disclaimers am I supposed to read?
  5. How can I download or order the data?
• Who wrote the metadata?

What does this data set describe?

1. How might this data set be cited?
   Stevens, Andrew W., Dartnell, Peter, Fregoso, Theresa A., Lacy, Jessica R., and Dailey, Evan T., 20200224, Single-beam bathymetry data collected in the Cache Slough Complex, Sacramento-San Joaquin Delta, California, during USGS field activities 2017-649-FA and 2018-684-FA: data release DOI:10.5066/P9AQSRVH, U.S. Geological Survey, Pacific Coastal and Marine Science Center, Santa Cruz, California.

   Online Links:

   • https://doi.org/10.5066/P9AQSRVH
   • https://www.sciencebase.gov/catalog/item/5d7192cce4b0c4f70cff9326?name=cs17_18_singlebeam_bathy.csv

   This is part of the following larger work.
   Fregoso, Theresa A., Stevens, Andrew W., Wang, Rueen-Fang, Handley, Thomas, Dartnell, Peter, Lacy, Jessica R., Ateljevich, Eli, and Dailey, Evan T., 2020, Bathymetry, topography, and acoustic backscatter data, and a digital elevation model (DEM) of the Cache Slough Complex and Sacramento River Deep Water Ship Channel, Sacramento-San Joaquin Delta, California: data release DOI:10.5066/P9AQSRVH, U.S. Geological Survey, Santa Cruz, CA.

   Online Links:

   • https://doi.org/10.5066/P9AQSRVH
   • https://www.sciencebase.gov/catalog/item/5d702b8ae4b0c4f70cfa990f

2. What geographic area does the data set cover?

   West_Bounding_Coordinate: -121.7483099
   East_Bounding_Coordinate: -121.6509921
   North_Bounding_Coordinate: 38.3364162
   South_Bounding_Coordinate: 38.2362289
   

3. What does it look like?

   https://www.sciencebase.gov/catalog/file/get/cs17_18_singlebeam_bathy.png (PNG)

   Map showing tracklines for single-beam bathymetry data collected in 2017 and 2018.

4. Does the data set describe conditions during a particular time period?

   Beginning_Date: 27-Jun-2017

   Ending_Date: 20-Dec-2018

   Currentness_Reference:

   ground condition at time data were collected

5. What is the general form of this data set?

   Geospatial_Data_Presentation_Form: comma-delimited text
   

6. How does the data set represent geographic features?
   1. How are geographic features stored in the data set?
      This is a Point data set. It contains the following vector data types (SDTS terminology):
      • Point (1683666)
   2. What coordinate system is used to represent geographic features?
      Horizontal positions are specified in geographic coordinates, that is, latitude and longitude. Latitudes are given to the nearest 0.0000001. Longitudes are given to the nearest 0.0000001. Latitude and longitude values are specified in Decimal degrees. The horizontal datum used is North American Datum of 1983.
      The ellipsoid used is GRS_1980.
      The semi-major axis of the ellipsoid used is 6378137.0.
      The flattening of the ellipsoid used is 1/298.257222101.
      

      Vertical_Coordinate_System_Definition:

      Altitude_System_Definition:

      Altitude_Datum_Name: North American Vertical Datum of 1988
      Altitude_Resolution: 0.01
      Altitude_Distance_Units: meters
      Altitude_Encoding_Method:

      Explicit elevation coordinate included with horizontal coordinates

7. How does the data set describe geographic features?

   Attribute Table

   Table containing attribute information associated with the dataset (Source: Producer defined)

   area

   Designation of sub-area within the Cache Slough Complex survey area (Source: producer defined)

   Value	Definition
   Cache Slough	Cache Slough sub-area
   Liberty Island	Liberty Island sub-area
   Little Holland	Little Holland Tract sub-area
   Wildlands	Wildlands sub-area

   datetime_utc

   The date and time of data collection in Coordinated Universal Time (UTC). (Source: Producer Defined)

   Range of values
   Minimum:	2017-06-27 15:40:30.193
   Maximum:	2018-12-20 00:12:02.461
   Units:	date and time in mm/dd/yyyy HH:MM:SS.FFF format

   longitude

   Longitude coordinate of data point relative to the North American Datum of 1983 (Source: Producer defined)

   Range of values
   Minimum:	-121.7483099
   Maximum:	-121.6509921
   Units:	Decimal degrees

   latitude

   Latitude coordinate of data point relative to the North American Datum of 1983 (Source: Producer defined)

   Range of values
   Minimum:	38.2362289
   Maximum:	38.3364162
   Units:	Decimal degrees

   easting_m

   East coordinate of data point relative to the North American Datum of 1983, projected in the Universal Transverse Mercator (UTM) Zone 10 North, meters, coordinate system (Source: Producer defined)

   Range of values
   Minimum:	609452.53
   Maximum:	617904.15
   Units:	meters

   northing_m

   North coordinate of data point relative to the North American Datum of 1983, projected in the Universal Transverse Mercator (UTM) Zone 10 North, meters, coordinate system (Source: Producer defined)

   Range of values
   Minimum:	4232848.31
   Maximum:	4243975.25
   Units:	meters

   ellipsoid_ht_m

   Height in meters of data point with reference to the reference ellipsoid (Source: Producer defined)

   Range of values
   Minimum:	-44.06
   Maximum:	-29.77
   Units:	meters

   ortho_ht_m

   Height in meters of data point with reference to the North American Vertical Datum of 1988. (Source: Producer defined)

   Range of values
   Minimum:	-12.01
   Maximum:	2.21
   Units:	meters

Who produced the data set?

1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
   • Andrew W. Stevens
   • Peter Dartnell
   • Theresa A. Fregoso
   • Jessica R. Lacy
   • Evan T. Dailey
2. Who also contributed to the data set?
3. To whom should users address questions about the data?
   PCMSC Science Data Coordinator

   U.S. Geological Survey, Pacific Coastal and Marine Science Center

   2885 Mission Street

   Santa Cruz, CA
   

   831-427-4747 (voice)

   pcmsc_data@usgs.gov

Why was the data set created?

These data were collected in support of ongoing field experiments and numerical modeling with the U.S. Bureau of Reclamation to improve our understanding of habitat quality, the influence on various landscape features on ecosystem function, and the effects of restoration actions in the Sacramento-San Joaquin Delta. These data are intended for science researchers, students, policy makers, and the general public.

How was the data set created?

1. From what previous works were the data drawn?
2. How were the data generated, processed, and modified?

   Date: 20-Dec-2018 (process 1 of 5)

   Bathymetry data were acquired during two field campaigns between 2017 and 2018 using single-beam sonar systems and global navigation satellite systems (GNSS) receivers mounted on personal watercraft (PWC). The sonar systems consisted of an Odom Echotrac CV-100 single-beam echosounder and 200 kHz transducer with a 9-degree beam angle. Raw acoustic backscatter returns were digitized by the echosounder with a vertical resolution of 1.25 cm. Depths from the echosounders were computed using sound velocity profiles measured using a YSI CastAway CTD during the survey. Positioning of the survey vessels was determined at 10 Hz using survey-grade GNSS receivers. Output from the GNSS receivers and sonar systems were combined in real time on the PWC by a computer running HYPACK hydrographic survey software. Navigation information was displayed on a video monitor, allowing PWC operators to navigate along survey lines at speeds of 2 to 3 m/s.

   Date: 31-Jan-2019 (process 2 of 5)

   Survey-grade positions of the PWCs were achieved using differential post-processing and data from nearby GNSS base stations. Positioning data from the GNSS receivers were post-processed using Waypoint Grafnav to apply differential corrections from a GNSS base station with known horizontal and vertical coordinates relative to the North American Datum of 1983 (2011 realization). Orthometric elevations relative to the NAVD88 vertical datum were computed using National Geodetic Survey Geoid12b offsets. Bathymetric data were merged with post-processed positioning data, spurious soundings were removed, and raw soundings were corrected in areas of dense aquatic vegetation using a custom Graphical User Interface (GUI) programmed with the computer program MATLAB.

   Date: 10-Sep-2019 (process 3 of 5)

   All available bathymetry data from the survey were compiled into a comma-delimited text file for distribution

   Date: 19-Oct-2020 (process 4 of 5)

   Edited metadata to add keywords section with USGS persistent identifier as theme keyword. No data were changed. Person who carried out this activity:
   

   U.S. Geological Survey

   Attn: VeeAnn A. Cross

   Marine Geologist

   384 Woods Hole Road

   Woods Hole, MA
   

   508-548-8700 x2251 (voice)

   508-457-2310 (FAX)

   vatnipp@usgs.gov

   Date: 13-Oct-2021 (process 5 of 5)

   Performed minor edits to the metadata to correct typos. No data were changed. Person who carried out this activity:
   

   U.S. Geological Survey

   Attn: Susan A. Cochran

   Geologist

   2885 Mission Street

   Santa Cruz, CA
   

   831-460-7545 (voice)

   scochran@usgs.gov

3. What similar or related data should the user be aware of?
   International Hydrographic Organization (IHO), 2008, IHO standards for hydrographic surveys (5th ed.): International Hydrographic Bureau Special Publication 44, 28p., Monaco.

   Online Links:

   • https://www.iho.int/iho_pubs/standard/S-44_5E.pdf

How reliable are the data; what problems remain in the data set?

1. How well have the observations been checked?
   No formal attribute accuracy tests were conducted.
2. How accurate are the geographic locations?
   Survey-grade positions of the personal watercraft (PWCs) were achieved with global navigation satellite system (GNSS) receivers and GNSS base stations placed on nearby benchmarks with published horizontal coordinates relative to the North American Datum of 1983 (2011 realization). Positioning data from the PWCs were post-processed using Waypoint Grafnav software to apply differential corrections from the GNSS base stations. Manufacturer reported accuracy for the differentially corrected horizontal positions for the GNSS rover trajectories is 0.8 cm + 0.5 ppm. The maximum baseline from the GNSS base stations was approximately 36 km, suggesting the minimum horizontal accuracy of survey vessel positions to be about 2.6 cm. Uncertainty in the horizontal positions associated with pitch and roll of the survey vessels is unknown.
3. How accurate are the heights or depths?
   Uncertainty in the final elevations is derived from the combination of uncertainty in the GNSS positioning and bathymetric sounding measurements. Manufacturer reported accuracy for the differentially corrected vertical positions for the GNSS rover trajectories is 1.5 cm + 1 ppm relative to the benchmark elevation. The maximum baseline from the GNSS base stations was approximately 36 km, suggesting the minimum vertical accuracy of survey vessel positions to be about 5.1 cm. The manufacturer of the single-beam echosounder used in this study reports a vertical accuracy of 1 cm. Additional uncertainty in the final computed elevations data is related to unmeasured variability in the speed of sound used to compute depths from bathymetric soundings and, thus, is depth-dependent. Based on analysis of available speed of sound measurements, we estimate uncertainties in the final depth soundings to be no greater than 1 percent of the water depth. The total vertical uncertainty is calculated using the constant- and depth-dependent factors summed in quadrature (International Hydrographic Organization, 2008). The estimated vertical uncertainty in final elevations is 6 cm and 11 cm for water depths of 2 m and 10 m, respectively. Uncertainty in the vertical positions associated with pitch and roll of the survey vessels is unknown.
4. Where are the gaps in the data? What is missing?
   Dataset is considered complete for the information presented, as described in the abstract. Users are advised to read the rest of the metadata record carefully for additional details.
5. How consistent are the relationships among the observations, including topology?
   All data falls within expected ranges.

How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?

Access_Constraints: none
Use_Constraints:

USGS-authored or produced data and information are in the public domain from the U.S. Government and are freely redistributable with proper metadata and source attribution. Please recognize and acknowledge the U.S. Geological Survey as the originator(s) of the dataset and in products derived from these data. This information is not intended for navigational purposes.

1. Who distributes the data set? (Distributor 1 of 1)
   
   U.S. Geological Survey - Science Base

   U.S. Geological Survey

   Denver Federal Center, Building 810, Mail Stop 302

   Denver, CO
   

   USA

   1-888-275-8747 (voice)

   sciencebase@usgs.gov
2. What's the catalog number I need to order this data set? Bathymetry data are available as a comma-delimited text file (cs17_18_singlebeam_bathy.csv), along with associated FGDC-compliant metadata.
3. What legal disclaimers am I supposed to read?

   Unless otherwise stated, all data, metadata and related materials are considered to satisfy the quality standards relative to the purpose for which the data were collected. Although these data and associated metadata have been reviewed for accuracy and completeness and approved for release by the U.S. Geological Survey (USGS), no warranty expressed or implied is made regarding the display or utility of the data on any other system or for general or scientific purposes, nor shall the act of distribution constitute any such warranty.

4. How can I download or order the data?
   • Availability in digital form:

     Data format:	comma-delimited text file in format comma-delimited text (version Matlab 9.6.0.1150989) text Size: 157.23
     Network links:	https://www.sciencebase.gov/catalog/file/get/5d7192cce4b0c4f70cff9326?name=cs17_18_singlebeam_bathy.csv https://www.sciencebase.gov/catalog/item/5d7192cce4b0c4f70cff9326 https://doi.org/10.5066/P9AQSRVH

   • Cost to order the data: None

Who wrote the metadata?

Dates:

Last modified: 13-Oct-2021

Metadata author:

PCMSC Science Data Coordinator

U.S. Geological Survey, Pacific Coastal and Marine Science Center

2885 Mission St.

Santa Cruz, CA

831-427-4747 (voice)

pcmsc_data@usgs.gov

Metadata standard:

Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)