etude de la qualite des eaux d'un hydrosysteme fluvial ... - LTHE

Before any simulation attempt, it should be noted that estimated boundary conditions are notdiurnally varied since the water level is not diurnally varied. Moreover rainwater is not takeninto account. Besides these disadvantages, the overall variation of these estimated boundaryconditions is similar to the monitored boundary conditions represented in the previoussection. The contents of organic matters, organisms and phosphate are low during high waterlevel and high when water level dropped.It is seen from figure 2.4.5 that turbidity in N3 (after the dam) changed abruptly. In order tofurnish the model a SPM boundary condition, the monitored turbidity was smoothed up andthe formula extrapolated from 2002 was employed to convert SPM from turbidity.SPM = 0.6158*Turbidity4.4.2.3. Initial conditions of biochemical variablesInitial conditions are achieved by two separate working steps. Firstly, a series of suitableequations are set up to calculate the given initial conditions from available data. These giveninitial conditions are usually related to the boundary condition at time zero of the simulation.Like the equations formulated in the steady state simulation, the given initial conditions arecalculated from loadings of variables at time zero. Then, the steady state initial conditions areautomatically computed by AQUASIM and are presented in the following figures.Figure 2.4.17: Initial condition of pHFigure 2.4.18: Initial condition of DO148