Introducing of Ce-Qual-W2 Model and Its Application - Water Quality Management: Assessment and Interpretation - page 95

Fig. 6.1 Schematic diagram
of interacting water quality
state variable (Khodadadi
Darban 2010 )

6.3.1 Boundary Conditions

Boundary conditions need to be speci ed in the water quality model at four

boundaries: the free surface, bottom, upstream and downstream boundaries. At the
free surface, the wind-induced DO aeration is incorporated into the model using the
equation developed by Banks and Herrera ( 1977 ).
There is no other mass uxes at the

bottom are specified specifically for each state variable by settling and benthic

flux through the free surface. The mass

fluxes. The contributions of non-point source loadings from the upstream drainage
area are speci fluxes at the upstream boundary for each of the state

variables (Khodadadi Darban 2010 ).
The surface elevation is speci

ed as mass

ed as a function of time either with harmonic
functions or with time-series data measured at this boundary. In calculating
velocities at the open boundary, the horizontal velocities are linearly extrapolated to
a fictitious model transecting outside the estuarine mouth, and the advective and

diffusive terms are calculated over this

fictitious model segment.

6.4 Study Area

6.4.1 The First Case Study

Karkheh dam is located 40 km far from West of Andimeshk city and 160 km far
from Ahwaz city. Figure 6.2 shows the location of the Dam. The main objective of