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 HYDRUS-1D Tutorial Example 2

#### Inverse Problem - One-Step Outflow Method

##### Project Manager
• Button "New"
• Name: Onestep
• Description: Onestep Outflow Method
• Button "OK"
##### Main Processes
• Check "Inverse Solution"
##### Inverse Solution
• Check "Soil Hydraulic Parameters"
• Check "No Internal Weighting"
• Max. Number of Iteration: 20
• Number of Data Points: 10
##### Geometry Information
• Number of Soil Materials: 2
• Number of Layers for Mass Balances: 2
• Depth of the Soil Profile: 4.52
##### Time Information
• Time Units: Hours
• Final time: 100
• Initial Time Step: 0.001
• Minimum Time Step: 0.0001
• Maximum Time Step: 10
##### Print Information
• Uncheck "Screen Output"
• Number of Print Times: 10
• Button "Select Print Times":
• 0.017
• 0.033
• 0.05
• 0.167
• 0.5
• 1.33
• 5.417
• 10
• 15
• 100
##### Water Flow - Iteration Criteria
• Upper Limit of the Tension Interval: 15000
##### Water Flow - Soil Hydraulic Parameters
• Initial Estimate:
• qr=0.15
• qs=0.388
• a=0.025
• n=1.5
• Ks=5.4
• l= 0.5
• Fitted: qr,a,n
• Second Material:
• qr=0
• qs=1
• a=1e-20
• n=1.001
• Ks=0.003
• l= 0.5
##### Water Flow - Boundary Conditions
• Upper Boundary Condition: Constant Flux
• Lower Boundary Condition: Constant Pressure Head
##### Water Flow - Constant BC
• Upper Boundary Flux: 0
##### Data for Inverse Solution
 0.017 -0.0786 0 2 1 0.033 -0.1616 0 2 1 0.05 -0.2097 0 2 1 0.167 -0.3408 0 2 1 0.5 -0.4456 0 2 1 1.033 -0.498 0 2 1 2.75 -0.5614 0 2 1 5.417 -0.5937 0 2 1 100 -0.6824 0 2 1 -15000 0.157 5 1 1

##### Soil Profile - Graphical Editor
• Menu: Options -> Grid - Height: 0.05
• Menu: Condition -> Profile Discretization
• Button "Number": 50
• Button "Insert Fixed" at 3.95 cm
• Button "Density": deselect "Use upper", upper density =0.1 at 3.95 cm
• Button "Edit condition"
• Select entire profile:
• Top value=-2
• Bottom value=2.52
• Deselect "Use top value for both"
• Lowest node = -1000 cm
• Menu: Condition -> Material Distribution
• Button "Edit condition"
• Select the ceramic plate and specify "Material Index"=2
• Ditto for "subregions"
• Observation Points?
##### Water Flow - Boundary Fluxes and Heads
• Cumulative Bottom Flux