we have the analytical solution in the CONDIN soubroutine of the Fortran file. we used Newton method.
the analytical solution is given by the following formula :
H0 = ZF(x) + H(x) + Q2/(2gL2H(x)2)
L the width of the channel,
ZF the cote of the bottom,
H the watter heiht.
Q the flow rate.
g the gravity acceleration.