Session 3A

Session 3A - Furrow irrigation with solute pulse

Project Manager Button “New”
Name: Furrow
Description: Furrow irrigation with solute pulse
Button “OK”

Main Processes Heading: Furrow irrigation with solute pulse
Check “Water Flow” and “Solute Transport”
Button “Next”

Geometry Information Type of Flow: Vertical Plane
Geometry Type: General
Number of materials: 1
Length Units: cm
Button “Next”

Time Information Time Units: Days
Final time: 100
Initial Time Step: 0.1
Minimum Time Step: 0.001
Maximum Time Step: 5
Button “Next”

Print Information Check All
Number of Print Times: 18
Button “Select Print Times”: 0.5, 1, 2.5, 5 10, 20, 30, 40, 50, 50.5, 51, 52.5, 55, 60, 70, 80, 90, 100
Button “Next”

Water Flow - Iteration Criteria Water content tolerance: 0.0005
Pressure head tolerance: 0.1
Lower Limit of the Tension Interval: 0.001
Upper Limit of the Tension Interval: 200
Button “Next”

Water Flow - Soil Hydraulic Model Button “Next”

Water Flow - Water Flow Parameters Catalog of Soil Hydraulic Properties: Silt
Button “Next”

Solute Transport - General Information Select GFE with artificial dispersion
Pulse Duration = 50 d
Button “Next”

Solute Transport - Solute Transport Parameters Diffusion Coefficient = 10
Disp.L = 1
Disp.T = 0.1
Button “Next”

Solute Transport - Transport Parameters CBound1=1
Button “Next”

Meshgen-2D: Geometry
Window Coordinates: X=150, Y=50, Width= 400, Hight=150
Set view Stretching factors according to given extents
Menu: Insert->Line->Graphically
Menu: Tools->Circle Input Mode->Center and Radius
Menu: Insert->Circle->Numerically: x=150, y=25, r=5
Save

Meshgen-2D: Boundary Points
Toolbar Button: “Edit Boundary Points”
Button “Number of Boundary Points”:
Outside boundary: 80
Drain:10
Button “Density”

Save

Meshgen-2D: FEM Mesh
Toolbar Button: “Edit FEM Mesh”
Button: Make mesh
Save
Exit

The BOUNDARY Module:

1. Initial Condition:
   Toolbar Button: “Initial Condition”
   Button “Select”: Select the entire transport domain
   Button “Set Value”: check “equilibrium from the lowest located nodal point.” And set equal to 50.
2. Water Flow Boundary Conditions:
   Toolbar Button: “Water Flow BC”
   Zoom in on the left furrow.
   1. Select “Constant pressure”, select bottom of the left furrow and 4 nodes on the side, specify 12 cm with equilibrium from the lowest located nodal point.
      Zoom on the drain.
   2. Select “Seepage face”: nodes along the drain.
      Default View.
3. Observation Nodes
   Toolbar Button: “Observation Points”
   Specify 5 points arbitrarily in the transport domain between source and drain
   Save
   Exit

Execute HYDRUS
(Execution time on P5-300 = 566)

OUTPUT:
Menu: Post-Processing ->Observation Points
Menu: Post-Processing ->Boundary Information->Solute Fluxes:
Seepage face flux
Cumulative Seepage face flux
Menu: Post-Processing ->Mass Balances Information
Menu: Post-Processing -> Graphical Display of Results
Pressure heads
Concentrations