224
B. Nilkens et al.
As mentioned before available data, which are necessary for calibration and
verification, are very heterogeneous. Thus, in situ investigations had to be carried
out, including sampling and analyzing water quality in the flowing wave and in
the sediment (BlOmeke 2000; Veenker 2001). Furthermore, erosion processes and
their impact on water quality were investigated with the in situ device
EROSIMESS (Myslisch 2000; Kral 2001). EROSIMESS was developed at the
IWW (Liem et al. 1997; Genent 2000).
Simulation of water quality has to be coupled directly to the water - balance
model ArcGRM, which is based on the Monte Carlo method. To achieve stable
statistical results, the number of 100 simulations for each month is recommended.
To preserve a maintainable total execution time it has to be a prime goal to optimize the running time of each quality module. Explicit algorithms to calculate hydraulics and water quality must be developed. Thus, simplification of complex differential equation systems and optimization or even prevention of time consuming
numerical operations is necessary.
The hydraulic characteristics, e.g. flow velocity u, water depth h and shear
stress T, which are essential for simulating the transport and transformation processes, are not calculated within the balance model. To evaluate these characteristics, the one-dimensional finite-difference model ESNA, which has been developed at the IWW, was used. Calibration and verification were carried out for each
river section, which is defined by gauging stations at the beginning and the end of
the section. Fig. 5 shows the calibration results for the River Spree section between the gauging stations Bautzen and Lieske.
B. Nilkens et al.
As mentioned before available data, which are necessary for calibration and
verification, are very heterogeneous. Thus, in situ investigations had to be carried
out, including sampling and analyzing water quality in the flowing wave and in
the sediment (BlOmeke 2000; Veenker 2001). Furthermore, erosion processes and
their impact on water quality were investigated with the in situ device
EROSIMESS (Myslisch 2000; Kral 2001). EROSIMESS was developed at the
IWW (Liem et al. 1997; Genent 2000).
Simulation of water quality has to be coupled directly to the water - balance
model ArcGRM, which is based on the Monte Carlo method. To achieve stable
statistical results, the number of 100 simulations for each month is recommended.
To preserve a maintainable total execution time it has to be a prime goal to optimize the running time of each quality module. Explicit algorithms to calculate hydraulics and water quality must be developed. Thus, simplification of complex differential equation systems and optimization or even prevention of time consuming
numerical operations is necessary.
The hydraulic characteristics, e.g. flow velocity u, water depth h and shear
stress T, which are essential for simulating the transport and transformation processes, are not calculated within the balance model. To evaluate these characteristics, the one-dimensional finite-difference model ESNA, which has been developed at the IWW, was used. Calibration and verification were carried out for each
river section, which is defined by gauging stations at the beginning and the end of
the section. Fig. 5 shows the calibration results for the River Spree section between the gauging stations Bautzen and Lieske.