Download "user manual"

d is defined as the average depth d = 1/2 (dl+d,). And the gradient S is defined
as S = (di-dr)/A. Again, all of these values are taken at the end of the time step
(Figure A.3, right-hand side).
The value 91, is the section inflow, q,, is the section outflow, di, the inflow
depth and d,, the outflow depth.. Thus, the assumption is that there is a linear decrease of flow and a linear surface profile over the section length, and
that the flow equation for the normal cell of section j now reads
The same equation is valid for the rising cell, because drb (being equal to zero)
is not present. For the specific equations for the inlet cell, the above equations
are used with q (being equal to 1/2 (q+q))on the left-hand side.
A2.3
Basic volume balance equations
General volume balance equation
The general volume balance equation for one section and one time step reads
where
V,i = net inflow volume over a time step
VS = surface volume
VI = - infiltrated volume
b,.e = subscripts indicating the beginning (b) and the end (e) of the time step
We developed the equations below for Vni (expressed in flow rates, q) for VS
and for VI. To continue, calculate the total volumes at the end of the time step
VS, and VI, and then subtract from them the values of vsb and V I b from the
end of the previous time step.
Net inflow equations
All net inflows are calculated as the difference between inflow and outflow in
a section and averaged over a time step. Thus, the general equation for the
net inflow v,i over a time step t b to t e reads
152