Northern California Base Flood Elevations

Frequently-anticipated questions:


What does this data set describe?

Title: Northern California Base Flood Elevations
Abstract:
The Base Flood Elevation, representing the elevation of the 100-year coastal flood, is derived for the entire California coastline. Elevation data is in NAVD88, rounded to the nearest half foot. Euclidean Allocation was used to extrapolate the elevations from the BFE line 10 kilometers inland from the coast. The extent of this dataset covers fthe California coast from the Oregon border south to Monterey Bay.
Supplemental_Information:
The Base Flood Elevation data was estimated by Philip WIlliams & Associates, LTD, under contract with the Pacific Institute, based on FEMA data. For details concerning methods, see the memorandum from PWA to the Pacific Institute.
  1. How should this data set be cited?

    Heberger, Matthew, and Herrera, Pablo, 2009, Northern California Base Flood Elevations: The Impacts of Sea-Level Rise on the California Coast, Pacific Institute, Oakland CA.

    Online Links:

    This is part of the following larger work.

    Heberger, Matthew, Cooley, Heather, Gleick, Peter, and Herrera, Pablo, 2009, The Impacts of Sea-Level Rise on the California Coast: Pacific Institute, Oakland.

    Online Links:

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -124.447423
    East_Bounding_Coordinate: -121.690851
    North_Bounding_Coordinate: 42.177310
    South_Bounding_Coordinate: 36.473470

  3. What does it look like?

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

    Beginning_Date: 1983
    Ending_Date: 2008
    Currentness_Reference: Based on FEMA flood study dates

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

    Geospatial_Data_Presentation_Form: raster digital data

  6. How does the data set represent geographic features?

    1. How are geographic features stored in the data set?

      This is a Raster data set. It contains the following vector data types (SDTS terminology):

      • String (582)
      It contains the following raster data types:
      • Dimensions 63217 x 22769 x 1, type Grid Cell

    2. What coordinate system is used to represent geographic features?

      Grid_Coordinate_System_Name: Universal Transverse Mercator
      Universal_Transverse_Mercator:
      UTM_Zone_Number: 10
      Transverse_Mercator:
      Scale_Factor_at_Central_Meridian: 0.999600
      Longitude_of_Central_Meridian: -123.000000
      Latitude_of_Projection_Origin: 0.000000
      False_Easting: 500000.000000
      False_Northing: 0.000000

      Planar coordinates are encoded using row and column
      Abscissae (x-coordinates) are specified to the nearest 10.000000
      Ordinates (y-coordinates) are specified to the nearest 10.000000
      Planar coordinates are specified in meters

      The horizontal datum used is North American Datum of 1983.
      The ellipsoid used is Geodetic Reference System 80.
      The semi-major axis of the ellipsoid used is 6378137.000000.
      The flattening of the ellipsoid used is 1/298.257222.

      Vertical_Coordinate_System_Definition:
      Altitude_System_Definition:
      Altitude_Datum_Name: North American Vertical Datum of 1988
      Altitude_Distance_Units: meters
      Altitude_Encoding_Method: Attribute values

  7. How does the data set describe geographic features?

    bfe_n_ras.vat

    Rowid
    Internal feature number. (Source: ESRI)

    Sequential unique whole numbers that are automatically generated.

    VALUE
    Value denotes the elevation of the BFE for the given cell, in NAVD88 centimeters.

    COUNT


Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)

  2. Who also contributed to the data set?

  3. To whom should users address questions about the data?

    Pacific Institute
    c/o Matthew Heberger
    Research Associate/GIS Manager
    654 13th Street
    Oakland, CA 94612
    USA

    (510) 251-1600 (voice)
    (510) 251-2203 (FAX)
    mheberger@pacinst.org

    Hours_of_Service: 9:00 AM to 5:00 PM


Why was the data set created?

This dataset was developed to estimate extents of flooding given the 100-year flood event for the Northern California coast. This layer is used as the base upon which impacts of a 1.4 meter sea-level rise are estimated.


How was the data set created?

  1. From what previous works were the data drawn?

    (source 1 of 1)
    Bob Battalio, PE, and Phillip Williams & Associates, LTD, 9/19/2008, Coastal Base Flood Elevation Estimates.

    Online Links:

    Type_of_Source_Media: ESRI shapefile

  2. How were the data generated, processed, and modified?

    Date: 1909 (process 1 of 3)
    See PWA memo for detailed methods on BFE estimation.

    Date: 1909 (process 2 of 3)
    BFE elevations were converted to meters, then meters were converted to centimeters so that data was stored as an integer for faster processing and minimizing file size.

    Date: 1909 (process 3 of 3)
    The Euclidean Allocation tool was used to extrapolate the flood elevation values to all cells within 10,000 meters surrounding the coastline.

  3. What similar or related data should the user be aware of?

    .

    This is part of the following larger work.

    ,.


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

  1. How well have the observations been checked?

    See PWA memorandum for methods and original FEMA Flood Insurance Studies for attrubute accuracy.

  2. How accurate are the geographic locations?

    See PWA memo, Ott_water_flood_elev.shp metadata, and FIS_flood_elev.shp metadata

  3. How accurate are the heights or depths?

  4. Where are the gaps in the data? What is missing?

    Data set has been visually inspected.

  5. How consistent are the relationships among the observations, including topology?

    The dataset is topologically correct.


How can someone get a copy of the data set?

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

Access_Constraints:
None. Data are freely downloadable and available for use in GIS and mapping subject the use constraints below.
Use_Constraints:
The data are freely redistributable with proper metadata and source attribution. Please reference the Pacific Institute as the originator of the dataset in any future products or research derived from these data. This information is being made available for informational purposes only. Users of this information agree by their use to hold blameless the State of California, and its respective officers, employees, agents, contractors, and subcontractors for any liability associated with its use in any form. This work shall not be used to assess actual coastal hazards, insurance requirements, or property values and specifically shall not be used in lieu of Flood Insurance Studies and Flood Insurance Rate Maps issued by the Federal Emergency Management Agency (FEMA).

  1. Who distributes the data set? (Distributor 1 of 1)

    Pacific Institute
    c/o Matthew Heberger
    Research Associate/GIS Manager
    654 13th Street,
    Preservation Park
    Oakland, CA 94612
    USA

    (510) 251-1600 (voice)
    (510) 251-2203 (FAX)
    mheberger@pacinst.org

    Hours_of_Service: 9:00 AM to 5:00 PM
  2. What's the catalog number I need to order this data set?

    Downloadable Data

  3. What legal disclaimers am I supposed to read?

    The data are freely redistributable with proper metadata and source attribution. Please reference the Pacific Institute as the originator of the dataset in any future products or research derived from these data.
    This information is being made available for informational purposes only. Users of this information agree by their use to hold blameless the State of California, and its respective officers, employees, agents, contractors, and subcontractors for any liability associated with its use in any form. This work shall not be used to assess actual coastal hazards, insurance requirements, or property values and specifically shall not be used in lieu of Flood Insurance Studies and Flood Insurance Rate Maps issued by the Federal Emergency Management Agency (FEMA).

  4. How can I download or order the data?

  5. What hardware or software do I need in order to use the data set?

    These data are available in Environmental Systems Research Institute (ESRI) shapefile format. The user must have ArcGIS or ArcView 3.0 or greater software to read and process the data file. In lieu of ArcView or ArcGIS, the user may utilize another GIS application package capable of importing the data. A free data viewer, ArcExplorer, capable of displaying the data is available from ESRI at www.esri.com.


Who wrote the metadata?

Dates:
Last modified: 19-Feb-2009
Metadata author:
Pacific Institute
c/o Matthew Heberger
Research Associate/GIS Manager
654 13th Street,
Preservation Park
Oakland, CA 94612
USA

(510) 251-1600 (voice)
(510) 251-2203 (FAX)
mheberger@pacinst.org

Hours_of_Service: 9:00 AM to 5:00 PM
Metadata standard:
FGDC Content Standards for Digital Geospatial Metadata (FGDC-STD-001-1998)
Metadata extensions used:


Generated by mp version 2.9.6 on Thu Feb 26 11:55:07 2009