SIMULATION
  SIMULATION_TYPE SUBSURFACE
  PROCESS_MODELS
    SUBSURFACE_FLOW flow
      MODE RICHARDS
    /
  /
END

SUBSURFACE

GRID
  TYPE structured
  NXYZ 10 1 1
  DXYZ
   2.5d0
   1.0d0
   1.0d0
  END
END

REGION all
  COORDINATES
    0.0d0 0.0d0 0.0d0
    25.0d0 1.0d0 1.0d0
  /
END

REGION left_end
  FACE WEST
  COORDINATES
    0.d0 0.d0 0.d0
    0.d0 1.0d0 1.0d0
  /
END

REGION right_end
  FACE EAST
  COORDINATES
    25.0d0 0.d0 0.d0
    25.0d0 1.0d0 1.0d0
  /
END

MATERIAL_PROPERTY beam
  ID 1
  POROSITY 0.20
  TORTUOSITY 1.d0
  ROCK_DENSITY 2.0d3 kg/m^3
  CHARACTERISTIC_CURVES cc1
  PERMEABILITY
    PERM_X 1.d-14
    PERM_Y 1.d-14
    PERM_Z 1.d-14
  /
END

CHARACTERISTIC_CURVES cc1
  SATURATION_FUNCTION VAN_GENUCHTEN
    LIQUID_RESIDUAL_SATURATION 0.5d-1
    M 0.75
    ALPHA 1.d-3
  /
  PERMEABILITY_FUNCTION MUALEM
    LIQUID_RESIDUAL_SATURATION 0.1d0
    M 0.5d0
  /
  PERMEABILITY_FUNCTION MUALEM_VG_GAS
    LIQUID_RESIDUAL_SATURATION 0.1d0
    GAS_RESIDUAL_SATURATION 0.1d0
    M 0.5d0
  /
END

EOS WATER
  # ref. density, ref. pressure, water compressibility
  DENSITY EXPONENTIAL 1000. 101325. 1.d-8
  VISCOSITY CONSTANT 0.864d-3 Pa-s
END

FLUID_PROPERTY
  DIFFUSION_COEFFICIENT 1.d-9
END

NUMERICAL_METHODS FLOW
  LINEAR_SOLVER
    SOLVER DIRECT
    LU_ZERO_PIVOT_TOL 1.d-20
  /
END

STRATA
  REGION all
  MATERIAL beam
END

TIME
  FINAL_TIME 0.20 day
  INITIAL_TIMESTEP_SIZE 1.d-4 day
  MAXIMUM_TIMESTEP_SIZE 0.0001 day at 0.d0 day
END

OUTPUT
  SNAPSHOT_FILE
    TIMES day 0.01 0.04 0.09 0.12
    NO_PRINT_INITIAL
    FORMAT HDF5
  /
END

FLOW_CONDITION initial
  TYPE
    LIQUID_PRESSURE dirichlet
  /
  LIQUID_PRESSURE 101325 Pa
END

FLOW_CONDITION left_end
  TYPE
    LIQUID_FLUX neumann
  /
  LIQUID_FLUX 0.d0 m/sec
END

FLOW_CONDITION right_end
  TYPE
    LIQUID_FLUX neumann
  /
  LIQUID_FLUX LIST
    # fluid_flux = (9.0d-6)*t [m/sec]
    TIME_UNITS day
    DATA_UNITS m/sec
    INTERPOLATION LINEAR
    #time  #fluid_flux
    0.00d0 0.0d0
    1.00d0 9.0d-6
  /
END

INITIAL_CONDITION initial
  REGION all
  FLOW_CONDITION initial
END

BOUNDARY_CONDITION left_end
  REGION left_end
  FLOW_CONDITION left_end
END

BOUNDARY_CONDITION right_end
  FLOW_CONDITION right_end
  REGION right_end
END

END_SUBSURFACE