Depth Grid of the Floodplain for the Winooski River through Waterbury, Vermont, Stage 431 feet.

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Frequently anticipated questions:


What does this data set describe?

Title:
Depth Grid of the Floodplain for the Winooski River through Waterbury, Vermont, Stage 431 feet.
Abstract:
Digital flood-inundation maps for a 8.3-mile reach of the Winooski River from 1,000 feet downstream of the Waterbury-Bolton town line upstream to 2,000 feet upstream of the Waterbury-Middlesex town line, were created by the U.S. Geological Survey (USGS) in cooperation with the Federal Emergency Management Agency. The inundation maps, which can be accessed through the USGS Flood Inundation Mapping Science Web site at <http://water.usgs.gov/osw/flood_inundation/>, depict estimates of the areal extent and depth of flooding corresponding to selected water levels (stages) at the USGS streamgage at Winooski River above Crossett at Waterbury, Vermont (station number 04288040). Current conditions at the USGS streamgage may be obtained on the Internet. In addition, the information has been provided to the National Weather Service (NWS) for incorporation into their Advanced Hydrologic Prediction Service (AHPS) flood warning system (http:/water.weather.gov/ahps/). The peak-stage information, also available on the Internet, may be used in conjunction with the maps developed in this study to show predicted areas of flood inundation. In this study, flood profiles were computed for the stream reach by means of a one-dimensional step-backwater model. The hydraulic model was then used to determine 8 water-surface profiles for flood stages at 2-ft intervals referenced to the streamgage datum and ranging from bankfull to approximately the 0.2-percent annual exceedance probability flood. The flood inundation area was modeled in a GIS by combining steady-state hydraulic modeling and available lidar digital elevation model (DEM) data. Information about the study, floods, and methods used can be found in the USGS Scientific Investigations Report 2015-5077. <http://pubs.usgs.gov/sir/2015-5077>.
Supplemental_Information:
A GIS application was used to produce a plane representing the flood water surface. The application duplicates the water-surface-elevation data from cross-section points across the flood plain perpendicular to the direction of the flood flow. Elevations between water-surface points on the cross-sections are proportional interpolations of the water-surface-elevation data and were positioned to generate a flood surface sloping with the water flow. A raster surface was created with the data points using a spline interpolation method, forming the estimated flood surface. A flood-depth grid was made by subtracting the DEM from the flood surface. The flood inundation areas are available in a GIS format, polyline shapefile, that provides extent of the flood peak for each stage level. This format allows the GIS data to be overlain on maps and aerial photographs, and to be used for various GIS applications, such as FEMA's Hazards U.S. Multi-Hazards (HAZUS-MH) program to estimate flood damages. For more information on data processing and checking procedures, see the full report at <http://pubs.usgs.gov/sir/2015/5077>. 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 ArcGIS format, this metadata file may include some ArcGIS-specific terminology.
  1. How should this data set be cited?

    U.S. Geological Survey, New England Water Science Center, 20150228, Depth Grid of the Floodplain for the Winooski River through Waterbury, Vermont, Stage 431 feet.: Scientific Investigations Report 2015-5077, U.S. Geological Survey, Reston, Virginia.

    Other_Citation_Details:
    Additional details regarding the development of the data can be found at Olson, S.A., 2015, Flood maps for the Winooski River in Waterbury, Vermont, 2014: U.S. Geological Survey Scientific Investigations Report 2015-5077, xx p.
    This is part of the following larger work.

    U.S. Geological Survey, New England Water Science Center, 20150331, Flood maps for the Winooski River in Waterbury, Vermont, 2014: U.S. Geological Survey Scientific Investigations Report 2015-5077.

    Online Links:

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -72.829939
    East_Bounding_Coordinate: -72.709793
    North_Bounding_Coordinate: 44.361253
    South_Bounding_Coordinate: 44.311089

  3. What does it look like?

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

    Calendar_Date: 04-Dec-2014
    Currentness_Reference: Generated in 2014

  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 raster data types:

      • Dimensions 2273 x 3922, type Grid Cell

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

      The map projection used is NAD 1983 StatePlane Vermont FIPS 4400 Feet.

      Projection parameters:
      Scale_Factor_at_Central_Meridian: 0.9999642857142858
      Longitude_of_Central_Meridian: -72.5
      Latitude_of_Projection_Origin: 42.5
      False_Easting: 1640416.666666667
      False_Northing: 0.0

      Planar coordinates are encoded using coordinate pair
      Abscissae (x-coordinates) are specified to the nearest 0.000000007286171666009978
      Ordinates (y-coordinates) are specified to the nearest 0.000000007286171666009978
      Planar coordinates are specified in foot_us

      The horizontal datum used is D North American 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.

  7. How does the data set describe geographic features?

    depth431, 04288040 (station ID)
    04288040 (station ID) flood inundation area (Source: U.S. Geological Survey)

    Entity_and_Attribute_Overview:
    Each entity corresponds to an estimated flood extent area for stream stages 417-431 feet at the USGS streamgage 04288040, Winooski River above Crossett Brook at Waterbury, Vermont. The attributes represent the depth range that correlates with the stage.
    Entity_and_Attribute_Detail_Citation:
    Olson, S.A., 2015, Flood Maps for the Winooski River at Waterbury, Vermont, 2014: U.S. Geological Survey Scientific Investigations Report 2015-5077, xx p.


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?

    U.S. Geological Survey, New England Water Science Center, in cooperation with the Federal Emergency Management Agency (FEMA).

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

    US Geological Survey, New England Water Science Center
    331 Commerce Way
    Pembroke, New Hampshire 03275

    (603)-226-7800 (voice)


Why was the data set created?

This dataset was created to support the development of flood inundation maps for documenting the extent of flooding along a reach of the Winooski River in Waterbury, Vermont


How was the data set created?

  1. From what previous works were the data drawn?

    LiDAR Chittenden Floodplain 2007 (source 1 of 1)
    Sanborn Map Company, Inc., 20070101, LiDAR Chittenden Floodplain 2007.

    Other_Citation_Details:
    The 8-foot DEM from lidar is the dominant elevation source for delineation of the flood boundary and computation of the depth grid.
    Type_of_Source_Media: None
    Source_Contribution: DEM from lidar data

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

    Date: 01-Oct-2014 (process 1 of 2)
    A GIS application was used to produce a plane representing the flood-peak water surface. The application duplicates water-surface-elevation data from cross-section points of the hydraulic model across the flood plain. Elevations between water-surface points on the cross-sections are proportional interpolations of the water-surface-elevation data and were positioned to generate a flood surface sloping with the water flow. A raster surface was created with the data points using a spline interpolation method, forming the estimated flood surface. A flood-depth grid was made by subtracting the DEM from the flood surface raster.

    Date: 01-Dec-2014 (process 2 of 2)
    Projected data set to Web Mercator Auxiliary Sphere (WKID 3857)

  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?

    Used cross-section data points from surveyed data, accurate to the datum of the survey. Flood inundation extent was manually checked. Complete for the intended 8.3-mile reach of the Winooski River in Waterbury, Vermont.

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

    Used cross-section data points from surveyed data, accurate to the datum of the survey. Flood inundation extent was manually checked. A separate review of the modeled flood extents and elevations was conducted.


How can someone get a copy of the data set?

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

Access_Constraints: None. This dataset is provided by USGS as a public service.
Use_Constraints:
Although these data have been used by the U.S. Geological Survey, U.S. Department of the Interior, no warranty expressed or implied is made by the U.S. Geological Survey as to the accuracy of the data. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the U.S. Geological Survey in the use of this data, software, or related materials. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. The flood boundaries shown were estimated using water stages at the USGS streamgaging station 04288040, Winooski River above Crossett Brook at Waterbury, Vermont, steady-state hydraulic modeling (assuming unobstructed flow) and a digital elevation model. The hydraulic model reflects the land-cover characteristics and any bridge, dam, levee, or other hydraulic structures existing July 2013. Unique meteorological factors (timing and distribution of storm) could cause actual streamflows along the modeled reach to vary from those assumed during a flood, which may lead to deviations from the water-surface elevations and inundation boundaries shown here. Additional areas may be flooded owing to unanticipated backwater from major tributaries along the main stem or from localized debris- or ice-jams. Inundated areas shown should not be used for navigation, regulatory, permitting, or other legal purposes. Although USGS intends to make this server available 24 hours a day, 7 days a week, timely delivery of data and products from this server through the Internet is not guaranteed. The USGS provides these maps "as-is" for a quick reference, emergency planning tool but assumes no legal liability or responsibility resulting from the use of this information. If this series of flood inundation maps will be used in conjunction with National Weather Service (NWS) river forecasts, the user needs to be aware of additional uncertainties which may be inherent or factored into NWS forecast procedures. The NWS uses river forecast models to estimate the quantity and timing of water flowing through selected river reaches in the United States. These forecast models (1) estimate the amount of runoff generated by a precipitation event, (2) compute how the water will move downstream, and (3) predict the flow and stage (water-surface elevation) for the river at a given location (Advanced Hydrologic Predictions Service forecast point) throughout the forecast period (every 6 hours and 3 to 5 days out in many locations). For more information on AHPS forecasts, please see <http://water.weather.gov/ahps/pcpn_and_river_forecasting.pdf>.

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

    US Geological Survey, New England Water Science Center
    331 Commerce Way
    Pembroke, New Hampshire 03275
    US

    603-226-7800 (voice)

  2. What's the catalog number I need to order this data set?

  3. What legal disclaimers am I supposed to read?

    Although these data have been used by the U.S. Geological Survey, U.S. Department of the Interior, no warranty expressed or implied is made by the U.S. Geological Survey as to the accuracy of the data. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the U.S. Geological Survey in the use of this data, software, or related materials. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. The flood boundaries shown were estimated using water stages at the USGS streamgaging station 04288040, Winooski River above Crossett Brook at Waterbury, Vermont, steady-state hydraulic modeling (assuming unobstructed flow) and a digital elevation model. The hydraulic model reflects the land-cover characteristics and any bridge, dam, levee, or other hydraulic structures existing July 2013. Unique meteorological factors (timing and distribution of storm) could cause actual streamflows along the modeled reach to vary from those assumed during a flood, which may lead to deviations from the water-surface elevations and inundation boundaries shown here. Additional areas may be flooded owing to unanticipated backwater from major tributaries along the main stem or from localized debris- or ice-jams. Inundated areas shown should not be used for navigation, regulatory, permitting, or other legal purposes. Although USGS intends to make this server available 24 hours a day, 7 days a week, timely delivery of data and products from this server through the Internet is not guaranteed. The USGS provides these maps "as-is" for a quick reference, emergency planning tool but assumes no legal liability or responsibility resulting from the use of this information. If this series of flood inundation maps will be used in conjunction with National Weather Service (NWS) river forecasts, the user needs to be aware of additional uncertainties which may be inherent or factored into NWS forecast procedures. The NWS uses river forecast models to estimate the quantity and timing of water flowing through selected river reaches in the United States. These forecast models (1) estimate the amount of runoff generated by a precipitation event, (2) compute how the water will move downstream, and (3) predict the flow and stage (water-surface elevation) for the river at a given location (Advanced Hydrologic Predictions Service forecast point) throughout the forecast period (every 6 hours and 3 to 5 days out in many locations). For more information on AHPS forecasts, please see <http://water.weather.gov/ahps/pcpn_and_river_forecasting.pdf>.

  4. How can I download or order the data?

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

    Data are supplied in ArcINFO format. Format compatibility is the user's responsibility.


Who wrote the metadata?

Dates:
Last modified: 02-Jun-2015
Metadata author:
US Geological Survey
Ask USGS - Water Webserver Team
507 National Center
Reston, Virginia 20192
US

1-888-275-8747 (1-888-ASK-USGS) (voice)

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


Generated by mp version 2.9.16 on Tue Jun 02 10:25:35 2015