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Time

  • start and end times are defined with respect to other temporal data.
  • These data are in units of seconds.
  • If these data are not provided, the simulation’s start time is assumed to be zero, and the end time is assumed to be the maximum allowable floating point value.
  • timeStep is a maximum time step that may be defined by the user. This will override the time step suggested by the CFL condition when applicable.
  • maxIterations is an optional user-defined maximum number of iterations for which the simulation will execute before termination.

Digital elevation model for topographic/bathymetric elevations.

  • elevationFile is a path to a raster in ARC/INFO ASCII grid format. The raster is assumed to use units of meters above some datum in the vertical dimension.
  • If a digital elevation model is not provided, a flat grid with 256x256 cells and a one meter grid cell size is instead initialized for the scenario.
  • metric is a Boolean variable defining if a grid uses UTM (i.e., metric) or decimal degree reference coordinates and cell sizes in the header metadata.

Conserved variables

  • Initial waterSurfaceElevation, horizontalDischarge, verticalDischarge, and/or depth values may be defined using ARC/INFO ASCII grids or float constants.
  • If undefined, waterSurfaceElevation assumes a grid equivalent to the digital elevation model. Also if undefined, horizontalDischarge, verticalDischarge, and depth grids are assumed to be filled with zeroes.

Bed friction

  • manningFile is a raster in ARC/INFO ASCII grid format.
  • manningValue is a single global roughness coefficient used over the domain.
  • These data must be defined in units of Manning’s roughness coefficient.
  • If frictional data are not defined, the bed surface is assumed to be frictionless.

Point sources

  • Some flooding phenomena may be described using one or multiple point sources from which water volume is temporally discharged.
  • This data is formatted using a comma-separated time series and a point location.
    • A comma-separated file may include a heading starting with a # symbol.
    • Units should be in the format of time (s), rate (cubic meters per second).
    • The point location must be defined using decimal degrees (if metric is defined as false) or metric (UTM) coordinates (if metric is defined as true).
  • Multiple point sources may be defined, but the number of points is typically small.

Rainfall

  • grid is a path to an ARC/INFO ASCII raster that spatially defines the amount of precipitation that falls over a given area (in meters) during the simulation.
  • stormCurve is a path to a CSV file that scales this amount of water temporally (e.g., an SCS or "design" storm curve) in an isotropic manner.
  • If rainfall is not defined, a rainfall rate of zero is assumed.

Soil parameters

  • The Green-Ampt infiltration model is used.
    • suctionHead is the wetting front soil suction head.
    • soilMoistureDeficit is the soil moisture deficit.
    • hydraulicConductivity is the saturated hydraulic conductivity.
  • suctionHead, soilMoistureDeficit, and hydraulicConductivity must each always be defined when modeling infiltration.
    • Each of these parameters may be defined using either an ARC/INFO ASCII grid or a single-valued float constant.
    • suctionHead is defined in units of meters; soilMoistureDeficit is unitless; and hydraulicConductivity is defined in units of meters per second.
  • If suctionHead, soilMoistureDeficit, or hydraulicConductivity is undefined, infiltration is not modeled.

Boundary conditions

  • east, west, north, and south boundaries may each be defined.
  • Boundary conditions include none, open, wall, criticalDepth, or marigram.
    • If undefined, boundary conditions are assumed as none.
    • marigram boundary conditions are typically used for simulating tsunamis.
      • The marigram is formatted as a comma-separated time series.
      • The comma-separated file may include a heading commented with a # symbol.
      • The comma-separated file should be with units of time (s), water surface elevation (m).
        • Care should be taken to ensure the water surface elevation never reaches a value less than the corresponding digital elevation model value along the boundary.
      • This marigram file should be specified as a marigram in the sources parameter category.

Output options

  • The output time step should be in units of seconds.
  • The output folder should be an existing directory on the user’s machine (and include a trailing /).
  • The following ARC/INFO ASCII grids may be outputted temporally: depth, waterSurfaceElevation, horizontalDischarge, verticalDischarge, unitDischarge, maxDepth, and maxUnitDischarge.
  • The following ARC/INFO ASCII grids may be outputted statically (but updated after each output timestep): maxDepth, maxUnitDischarge.
  • To keep track of volume conservation error, the following may be toggled (via Boolean variables) to output via command line: printTime, printTimeStep, printIteration, printVolumeComputed, printVolumeAdded, printVolumeConservationError.
    • These values will be printed during each output time step.

Constants

  • Gravitational acceleration may be defined; if not, 9.80665 m/s^2 is assumed.
  • The velocity desingularization constant may be defined; smaller values indicate the depths at which velocities are corrected using the desingularization function. If not, a value of sqrt(0.01*max(max(1.0, dx), dy)) is assumed.
  • The machine epsilon may be redefined. This value controls the minimum depth, below which depths are numerically truncated to be zero.
  • The use of the wet cell tracking algorithm is defined as a Boolean variable.
    • This should be true when simulating sparse events (e.g., point sources) and false when simulating wide area inundation (e.g., extreme rainfall).