#=========================== numerical methods ================================
NUMERICAL_METHODS TRANSPORT

  NEWTON_SOLVER
    # Uncomment to debug reactions
    #NUMERICAL_JACOBIAN
  /

  LINEAR_SOLVER
    SOLVER DIRECT
  /

END

#=========================== regression =======================================
REGRESSION
  CELL_IDS
    1
  /
END

#=========================== flow mode ========================================
# Uniform velocity (see below). No flow mode specified.

#=========================== useful tranport parameters ==================
SPECIFIED_VELOCITY
  UNIFORM? YES
  DATASET 0.d0 0.d0 0.d0 
END

#=========================== discretization ===================================
GRID
  TYPE STRUCTURED
  NXYZ 1 1 1
  BOUNDS
    0.d0 0.d0 0.d0
    1.d0 1.d0 1.d0
  /
END

#=========================== fluid properties =================================
FLUID_PROPERTY
  DIFFUSION_COEFFICIENT 1.d-9
END

#=========================== material properties ==============================
MATERIAL_PROPERTY soil1
  ID 1
  POROSITY 0.25d0
  TORTUOSITY 1.d0
END

#=========================== output options ===================================
OUTPUT
#  PERIODIC_OBSERVATION TIMESTEP 1
END

#=========================== times ============================================
TIME
  FINAL_TIME 25.d0 y            ! A(aq) at 50m midpoint
  INITIAL_TIMESTEP_SIZE 1.d0 h
  MAXIMUM_TIMESTEP_SIZE 2.5d-1 y
#  MAXIMUM_TIMESTEP_SIZE 1.d-3 y
END

#=========================== regions ==========================================
REGION all
  COORDINATES
    -1.d20 -1.d20 -1.d20
    1.d20 1.d20 1.d20
  /
END

REGION pt
  COORDINATE 0.5d0 0.5d0 0.5d0
END

#=========================== observation points ===============================
OBSERVATION
  REGION pt
END

#=========================== transport conditions =============================
TRANSPORT_CONDITION initial
  TYPE ZERO_GRADIENT
  CONSTRAINT_LIST
    0.d0 initial
  /
END

#=========================== constraints ======================================
CONSTRAINT initial
  CONCENTRATIONS
    A(aq) 1.d-4  T
    B(aq) 1.d-3  T
    C(aq) 1.d-7  T
  /
  IMMOBILE
    D(im) 1.d-7
  /
END

#=========================== condition couplers ===============================
# initial condition
INITIAL_CONDITION
  TRANSPORT_CONDITION initial
  REGION all
END

#=========================== stratigraphy couplers ============================
STRATA
  REGION all
  MATERIAL soil1
END
