1. Transport Processes in a 1D System
Case of a River

2. What is a river? 'grid definition Type grid 'Channel Length
Length As Double
'Channel cross Section
AreaVertical As Double
waterdepth As Double
'Channel Horizontal Surface
width As Double
HorizontalArea As Double
'number of cells
NC As Integer
‘cells length (spatial step)
dx As Double
'distance of cell center to origin
xc() As Double
End Type

3. How to describe the Flow in a River
Type Flow_properties
Velocity As Double
Discharge As Double
Diffusivity As Double
FourierNr As Double
DiffusionNr As Double
CourantNr As Double
End Type
In a real river the flow changes along the river. In this course we are going to consider a schematic river where the flow is uniform along the river.

4. Control Parameters Type Controls t As Double TimeDays As Double
dt As Double
tstart As Double
tend As Double
printtime As Double
Printnumber As Double
NumberOfOutputs As Integer
DtPrint As Double
PrintLine As Integer
FirstPrintLine As Long
FirstOutput As Boolean
Advection As Boolean
Diffusion As Boolean
AdvType As String
Explicit As Boolean
End Type
Control Parameters

5. Boundary Conditions Type Discharge_properties Type BoundaryCondition
LeftType As Integer
LeftValue As Double
RightType As Integer
RightValue As Double
PropDischarges As Discharges
End Type
Type Discharge_properties
Number As Integer
Name As String
Cell As Integer
VolumeRate As Double
SpecificValue As Double
End Type
Type Discharges
NumberOfDischarges As Integer
Discharge() As Discharge_properties
End Type

6. A Property Type Property Old() As Double NewValue() As Double
Default As Double
minimum As Double
maximum As Double
MinimumActive As Boolean
MaximumActive As Boolean
RatioToC As Double
RatioToPlot As Double
DecayRate As Double
GrowthRate As Double
GrazingRate As Double
GrazingEff As Double
GrazingKsat As Double
ExcretionRate As Double
TminToGrow As Double
TmaxToGrow As Double
ToptToGrow As Double
LminToGrow As Double
LmaxToGrow As Double
LoptToGrow As Doub
Boundary As BoundaryCondition
SheetName As String
Calc_As As PropCalcMethod
InitCell As Integer
End Type
Type PropCalcMethod
Method As String
Imposed_TimeSeries() As Double
N_Instants As Double
N_interval As Integer
SinusAmplitude As Double
SinusPhaseVel As Double
SinusPhase As Double
SinusAverage As Double
End Type

7. Properties Type Properties ' Prey As Property ' Predator As Property
' Detritus As Property
Temperature As Property
Generic As Property
' Nutrient As Property
End Type

8. Equations Type Equation_Coef Left2Coef() As DoubleCi
Ci-1
Ci+1
Type Equation_Coef
Left2Coef() As Double
LeftCoef() As Double
CenterCoef() As Double
RigthCoef() As Double
Rigth2Coef() As Double
TiCoef() As Double
End Type

9. Atmosphere Type Atmosphere Atm_Temp_Default As Double
Atm_Humidity_Default As Double
Atm_Radiation_Default As Double
Atm_Wind_Default As Double
Sky_Temp_Default As Double
Atm_Temperature () As Double
Atm_Humidity () As Double
Atm_Radiation () As Double
Atm_Wind () As Double
Sky_Temp () As Double
 Calc_As As PropCalcMethod
End Type