Amy C. Foxgrover Patrick L. Barnard 2012 Version 1.0 polygon shapefile Amy C. Foxgrover Patrick L. Barnard 2012 Version 1.0 U.S. Geological Survey Data Series Data Series 684 https://doi.org/10.3133/ds684 A GIS polygon shapefile outlining the boundaries of the native input datasets used to construct a seamless, 2-meter resolution digital elevation model (DEM) was constructed for the open-coast region of the San Francisco Bay Area (outside of the Golden Gate Bridge), extending from Half Moon Bay to Bodega Head along the North-central California coastline. The goal was to integrate the most recent high-resolution bathymetric and topographic datasets available (for example, Light Detection and Ranging (lidar) topography, multibeam and single-beam sonar bathymetry) into a seamless surface model extending offshore at least 3 nautical miles and inland beyond the +20 m elevation contour. This DEM data set was constructed to provide critical model boundary conditions (bathymetry and topography) necessary to predict the impacts of severe winter storms and sea level rise along this stretch of coast, using the Coastal Storm Modeling System (CoSMoS). This process based modeling system was first applied along the coast of Southern California (Barnard and others, 2009). CoSMoS can be run in real-time or with prescribed scenarios, incorporating atmospheric forcing information (wind and pressure fields) with a suite of state-of-the-art physical process models (WaveWatch3, SWAN, XBeach, Delft3D) to enable detailed prediction of water levels, run-up, wave heights, and currents, ultimately predicting the spatial distribution of coastal flooding, inundation, erosion, and cliff failure. The DEM was constructed to define the general shape of the nearshore, beach and cliff surfaces as accurately as possible, with less emphasis on the detailed variations in elevation inland of the coast and on bathymetry inside harbors. As a result this DEM should not be used for navigation purposes. Additional information about the USGS field activities from which some of these data were derived is available online at: https://cmgds.marine.usgs.gov/fan_info.php?fan=o1209ca Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Although this Federal Geographic Data Committee-compliant metadata file is intended to document the dataset in nonproprietary form, as well as in ArcInfo format, this metadata file may include some ArcInfo-specific terminology. 1984 2011 topography at time underlying dataset was collected (See Source Information) Complete None planned -123.158145 -122.393965 38.352385 37.407828 USGS Metadata Identifier USGS:40f91241-71e0-48ce-baf6-2584979ca058 None coastal beaches ocean ISO 19115 Topic Category elevation geoscientificInformation oceans USGS Thesaurus bathymetry bathymetry measurement sea-floor characteristics geospatial datasets digital elevation models hazards Global Change Master Directory (GCMD) BATHYMETRY SEAFLOOR TOPOGRAPHY Light Detection and Ranging Multibeam Swath Bathymetry System Digital Elevation Model None Central California California USA Geographic Names Information System (GNIS) Half Moon Bay Pacifica Daly City Bolinas Palomarin Beach Wildcat Beach Drakes Bay Point Reyes Point Reyes Beach Abbotts Lagoon San Francisco Bay Tomales Point Tomales Bay Bodega Bay San Mateo County San Francisco County Marin County Sonoma County State of California GEOnet Names Server North Pacific Ocean None Majority of data (that is, lidar, multibeam bathymetry) derived from topographic/bathymetry data collected at 1-2 m horizontal resolution, with vertical uncertainty at time of data collection ranging from 10 cm to 1 m. Use at greater scales not advised. See full Data Series report for more information: Foxgrover, A.C., and Barnard, P.L., 2012, A seamless, high-resolution digital elevation model (DEM) of the north-central California coast: U.S. Geological Survey Data Series 684, 11 p. and datasets, available at https://doi.org/10.3133/ds684/. U.S. Geological Survey, Pacific Coastal and Marine Science Center PCMSC Science Data Coordinator mailing and physical address

2885 Mission Street

Santa Cruz CA 95060 USA 831-427-4747 pcmsc_data@usgs.gov California State University, Monterey Bay (CSUMB) and Fugro Pelagos, Inc., for California State Waters Mapping Project (CSWMP) from Pat Iampietro; Pillar Point Harbor from Anne Sturm (U.S. Army Corps of Engineers); National Geophysical Data Center (NGDC); National Oceanic and Atmospheric Administration (NOAA); Marin County from Brian Quinn (County of Marin GIS Division of Community Development Agency); Bolinas Lagoon from Matt Brennan (ESA-PWA); Carignan, K.S., Taylor, L.A., Eakins, B.W., Caldwell, R.J., Friday, D.Z., Grothe, P.R., and Lim, E., 2011, Digital elevation models of central California and San Francisco Bay: Procedures, data sources and analysis: NOAA Technical Memorandum NESDIS NGDC-52, 49 p. and datasets, available at http://www.ngdc.noaa.gov/dem/squareCellGrid/download/741 Microsoft Windows 7 enterprise; ESRI ArcCatalog 10.0, Build 3600, Service Pack 3 Refer to the DEM Accuracy and Limitations section in this Data Series for an explanation of the accuracy of the identification of the entities and assignments of values in the dataset and a description of the tests used. Refer to the DEM Construction Methods section in this Data Series for an explanation of the fidelity of relationships in the dataset and tests used. Refer to the DEM Construction Methods section in this Data Series for information about omissions, selection criteria, generalization, definitions used, and other rules used to derive the dataset. Refer to the DEM Accuracy and Limitations section in this Data Series for an explanation of the accuracy of the horizontal coordinate measurements and a description of the tests used. Refer to the DEM Accuracy and Limitations section in this Data Series for an explanation of the accuracy of the vertical coordinate measurements and a description of the tests used. California State University, Monterey Bay Unknown contact: Pat Iampietro <pat_iampietro@csumb.edu> http://seafloor.csumb.edu/SFMLwebDATA.htm digital data - raster grids or ascii xyz text files 2006 2010 ground condition CSUMB Provided multibeam bathymetry for entire offshore study area. U.S. Geological Survey, lidar acquired by Terrapoint Unknown contact: Carol Ostergren <costergren@usgs.gov> http://lidar.cr.usgs.gov/ digital data - raster grids 201006 201011 ground condition USGS Provided topographic lidar data for coastal region (to approximately +10 m elevation contour) for stretch of coast from Point Reyes to Point San Pedro San Francisco State University, lidar acquired by Earth Eye Unknown contact: Ellen Hines <ehines@sfsu.edu> digital data - raster grids or ascii xyz text files 201004 201007 ground condition SFSU Provided topographic lidar data for Marin County, San Francisco County, and portions of San Mateo and Sonoma counties. California State Ocean Protection Council Unknown contact: Sheila Semans <ssemans@scc.ca.gov> digital data - raster grids 201009 201012 ground condition OPC Provided topographic lidar data in the vicinity of Bodega Bay and the southernmost region of Half Moon Bay (areas not covered by USGS or SFSU 2010 lidar) NOAA National Geophysical Data Center 2011 http://www.ngdc.noaa.gov/dem/squareCellGrid/download/741 digital data - raster grids 1922 2009 ground condition NGDC Provided data for entire study area. U.S. Army Corps of Engineers Unknown digital data - terrain dataset 200909 200910 ground condition USACE Provided bathy/topo DEM of Pillar Point Harbor U.S. Geological Survey 2008 USGS OFR 2008-1237 digital data - raster grids 200411 200608 ground condition USGS Provided bathymetry data for Tomales Bay GIS Division of Community Development Agency County of Marin unknown contact: Brian Quinn <BQuinn@co.marin.ca.us> digital data - raster terrain datasets 1931 2011 ground condition none Provided bathy/topo terrain dataset for Marin County Environmental Science Associates, Philip Williams and Associates Unknown contact: Matt Brennan <MBrennan@esassoc.com> digital data - raster grids 1998 ground condition ESA PWA Provided bathymetry for Bolinas Lagoon U.S. Geological Survey Unknown contact: Dan Hoover <dhoover@usgs.gov> https://cmgds.marine.usgs.gov/fan_info.php?fan=o1209ca digital data - TIN converted to a raster 200911 ground condition USGS Provided data from Ocean Beach, San Francisco ATV/PWC survey U.S. Geological Survey 1991 http://pubs.usgs.gov/of/1991/0145/report.pdf map - bathymetry contours 1984 1986 ground condition USGS Provided bathymetry for Drakes Estero (Summary) Performed by Amy Foxgrover and Patrick Barnard: ArcGIS was the primary software used for DEM construction. For each individual DEM, the native datasets were mosaicked into a single grid to preserve the original surfaces as closely as possible. Prior to mosaicking, datasets were gridded and (or) resampled to 2 m resolution (if necessary), and their spatial extents modified according to the following guidelines: 1. Data sets of comparable quality (for example, overlapping multibeam data), collected over the same time period were not clipped. In these instances the overlapping regions were blended together using the "Blend" algorithm in the Mosaic to New Raster tool in Arc Toolbox. The exception to this is for topographic data along the shoreline. Multiple high-resolution aerial lidar surveys were collected along the shoreline in 2010. Since the nearshore is a very dynamic region that can be modified greatly by a single storm event, rather than blending multiple high-resolution datasets (which could produce unrealistic beach morphology), data from a single time period were selected for use. Where possible, we used data collected in the fall for nearshore elevations to minimize the potential of winter storm effects. 2. In overlapping regions where the quality of one dataset was clearly inferior to the other (for example, regional 10-m resolution DEMs overlapping with 2-m resolution lidar), the spatial extent of the inferior data set was clipped so there was minimal overlap, typically about ~20 m, with the superior dataset. The overlapping regions then were smoothed together using the Blend algorithm. This range of overlap was found to be the most efficient for ensuring a smooth transition between datasets while minimizing the use of lower quality data. The spatial extent of each dataset used is included as a GIS shapefile. In addition, the areas of overlap were typically well outside of the dynamic coastal zone, which was typically covered by a single lidar pass, so any blending should have minimal impact for this important region. 2011 >(Detailed DEM Construction Procedures) Performed by Amy Foxgrover and Patrick Barnard: > >1. Divide study area into ~10 km alongshore segments > A. Define DEM coverage area/polygon that extends ~10 km alongshore, from 3 nautical > miles offshore inland beyond the +20 m topographic contour > B. Ensure that adjacent DEM coverage areas overlap by ~250 m >2. Acquire most recent or highest resolution data sets in DEM coverage areas > A. Lidar > B. Multibeam bathymetry > C. Local high-resolution beach topography (usually ATV-acquired) and nearshore bathymetry > (usually PWC-acquired). >3. Fill gaps with older/lower resolution datasets > A. Lower resolution DEMs - for example, NGDC's 10-m resolution tsunami inundation DEM, > (Carignan and others, 2011) in Bodega Harbor > B. Bathymetric data derived from single beam bathymetry - for example, 1980s survey in Drakes > Estero and 1998 bathymetry in Bolinas Lagoon >4. Convert all datasets into identical horizontal coordinate system, vertical datum, and grid resolution > A. Horizontal coordinate system: UTM NAD83 Zone 10 North > B. Vertical Datum: NAVD88 > I. If different [usually Mean Lower Low Water (MLLW)], convert using local NOAA tide station information > [http://tidesandcurrents.noaa.gov/ (last accessed December 12, 2011)] based on survey metadata > C. Grid resolution: 2 m > I. If already gridded at higher resolution(<2 m), resample to 2 m using bilinear interpolation > II. If already gridded at a lower resolution (> 2m), export as xyz file, reimport as xyz points, create TIN > (triangular irregular network), create 2-m grid from TIN using linear interpolation of the TIN triangles, > and clip to survey extent > III. Ungridded: > a) Lower resolution surveys (for example, PWC-collected bathymetry): create TIN from points then > convert to 2-m grid using linear interpolation of the TIN triangles >5. Clip datasets to DEM/coverage needs, if necessary > A. Useful for data management and processing efficiency > B. Necessary for very large data sets, such as county-wide lidar datasets (for example, Golden Gate Lidar Project data) > C. Remove ocean water surfaces and offshore rocky outcrops/islands > I. Aerial topographic lidar from 2010 was provided as bare-earth hydro-flattened DEMs. The breakline polygons provided > with aerial lidar data were used to generate 2-m resolution grids of water surfaces over the ocean or tidal embayments > where bathymetric data was to be inserted. Use this grid to mask out water surfaces in the topographic DEM using the > Set Null tool in Arc Toolbox. > II. Hydro-flattened surfaces of small inland water bodies were retained in the final DEM. Since these areas are of less > importance for this research, no attempt was made to obtain bathymetric depths for these inland ponds or lakes (for example, > Lake Merced in San Francisco). Hydro-flattened features that were retained in the final DEM are provided in shapefile format > at the end of this report. > III. Extract small islands and rocky outcrops from topographic lidar datasets using breaklines provided. These features are > not included in the nearshore interpolation, but are incorporated into the final DEM in step 8. >6. Manage overlapping datasets > A. Data sets were allowed to overlap extensively only if they are from the same time period, of comparable quality, and not within > the dynamic nearshore region, otherwise allow only minimal (~10-30 m) overlap to ensure smooth DEM transitions > B. Clip low-resolution data sets pushed to 2-m resolution, such as Personal Watercraft data and regional DEMs, to minimal overlap > with adjacent high-resolution data sets (usually multibeam and topographic lidar) > C. Clip topographic lidar so that only a single dataset is used for the coastal zone. Where it exists, the USGS lidar is given highest > preference in the nearshore zone because it was collected in the summer and fall of 2010 when the beach morphology was less likely to > influenced by winter storm events. The Golden Gate Lidar Project data are used for all reaches landward of the USGS lidar coverage (roughly > 10-m elevation and higher) and along the coastline where USGS lidar was not collected. The OPC lidar is present only in two small sections > that are not covered by USGS or GGLP lidar (within DEM sections 1 and 14). >7. Fill in data gaps between high-resolution datasets > A. If no high-resolution data are available between the offshore multibeam bathymetry and coastal topographic lidar in protected > harbors/embayments, or in other areas where interpolation from surrounding data sets will create a surface unlikely to reflect actual > bathymetry/topography accurately, fill in gaps with regional DEMs or other low-resolution data sets. Otherwise, interpolate across gaps. > I. Filling in harbors or embayments using regional DEMs/other low-resolution data: > a) Clip best available regional DEM or bathymetry to gap area, allowing only minimal overlap (~20 m) with adjacent high-resolution > data sets > b) Export clipped grid as xyz, reimport as points, create TIN, create 2-m grid from TIN, clip to gap extent > II. Interpolation across nearshore gaps: > a) Create preliminary DEM using Mosaic tool with the following settings: > Coordinate System: UTM Zone 10 North > Pixel Type: 32 Bit Float > Cell Size: 2 > Mosaic Method: Blend > Mosaic Color Map: Last > b) Create polygon of data gap(s) to fill within the preliminary DEM surface > c) Buffer the data gap polygon with a linear distance of 20 m using the Buffer tool in Arc Toolbox > d) Clip preliminary DEM using the buffered polygon, export clipped grid as xyz, reimport as points (fig. 3B), create TIN, create 2-m > grid from TIN, clip to buffered gap extent > III. Interpolation around perimeter of Bolinas Lagoon and Drakes Estero: > a) Fill any narrow gaps between bathymetry grids of Bolinas Lagoon and Drakes Estero and the nearest high resolution topography > using the same procedure as used above for interpolating across nearshore gaps. >8. Compile final DEMs > A. Load all datasets for DEM > B. Verify all significant data gaps filled (few missing cells OK) in DEM coverage area > C. Build interim DEM using Mosaic to New Raster tool in ArcGIS with same setting as noted above in Step 7 > D. Build final DEM using Mosaic to New Raster tool in ArcGIS. Input rasters are the above interim DEM and a grid of small islands or rocky > outcrops obtained from lidar. The islands are given top priority in the mosaicking algorithm so that island elevations from the lidar overwrite > elevations from the nearshore interpolation. > E. Clip output to DEM coverage area > F. Create contours and plot cross-shore profiles to verify data quality and consistency 2011 Edited metadata to add keywords section with USGS persistent identifier as theme keyword. No data were changed. 20201019 U.S. Geological Survey VeeAnn A. Cross Marine Geologist Mailing and Physical

384 Woods Hole Road

Woods Hole MA 02543-1598 508-548-8700 x2251 508-457-2310 vatnipp@usgs.gov Edited metadata to add USGS Thesaurus keywords and perform minor edits to bring the metadata up to current PCMSC standards. No data were changed. The metadata available from a harvester may supersede metadata bundled within a download file. Users are advised to compare the metadata dates to determine which metadata file is most recent. 20211020 U.S. Geological Survey Susan Cochran Geologist Mailing and Physical

2885 Mission Street

Santa Cruz CA 95060 831-460-7545 scochran@usgs.gov Vector G-polygon 1023 Universal Transverse Mercator 10 0.999600 -123 0.000000 500000.000000 0.000000 coordinate pair 0.000001 0.000001 meters North American Datum of 1983 Geodetic Reference System 80 6378137.000000 298.257222 > Polygon attributes > Data_type = type of data (bathymetry, lidar, etc.) > Date = date of data collection > Agency = agency that collected the data or commissioned its collection > Native_res = native horizontal resolution of the source data > Survey_ID = survey ID used in website or data report none U.S. Geological Survey (USGS) Patrick L Barnard Research Geologist mailing and physical address

USGS, 400 Natural Bridges Drive

Santa Cruz CA 95060 USA (831) 460-7556 pbarnard@usgs.gov U.S. Geological Survey Data Series 684 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. shapefile 10.0 windows winzip or unix gunzip 7.8 https://doi.org/10.3133/ds684 none 20211020 U.S. Geological Survey, Pacific Coastal and Marine Science Center PCMSC Science Data Coordinator mailing and physical address

2885 Mission Street

Santa Cruz CA 95060 USA 831-427-4747 pcmsc_data@usgs.gov Content Standard for Digital Geospatial Metadata FGDC-STD-001-1998