Application of the Integrated Water Management Approach
219
into contact with the air. This enabled the oxidation of iron sulphides, e.g. pyrite.
Its products, iron and sulphates, are washed into the open pits by returning
groundwater. The consequence is an acidification of the lake water down to pH 2.
This has to be avoided because the open pits are intended as lakes mainly for recreational use. Much research has been done to find ways to stop this process, but
up to now the only practicable way is to hinder the infiltration of groundwater into
the lakes. Therefore they have to be filled artificially with water from the River
Spree. The lake water will still be acid, but at a much more acceptable level.
The Upper River Spree passes very close to quarrying sites, both active and
closed down, so that, additionally, acidic groundwater infiltrates directly the river.
Once the lakes are filled, water from the river will still be led through the lakes to
dilute the acid water as much as possible. The water returning into the river will
therefore also be acidic. Until today it is unknown how much of the acidic water
the River Spree can take without creating further problems.
4 Objectives
The main objective of the joint task is to develop a water management tool for the
catchment area of the River Spree. The environmental offices of the federal states
of Saxony and Brandenburg have to manage the water quantity in the catchment
area of the River Spree in such a way as to find the optimum between the contradicting demands. The Spree model will be used as a decision - support system in
these cases. The objective is to predict the water quality until the year 2035, depending on the chosen water quantity management strategies.
The model user prefers to run the model within a couple of hours, as a variety
of management strategies for each hydrological situation will have to be analyzed.
Therefore, the calculation time has to be limited to a few hours at maximum. The
total running time is the main reason why no existing models, which are normally
of complex structure, could bee used in this case.
Another reason not to apply any existing water - quality model is the required
list of simulated parameters. Due to the influence of the lignite mining industry
and others, parameters such as iron, sulphate and pH value are offar higher importance to the total quality situation than in other catchment areas. Processes are taking place in completely different dimensions. Commercial models would have to
be enhanced in order to meet the requirements of the concerns of the research
area. The only way to comply with all requirements was to develop a new model
(Schlaeger and Kongeter 2001).
An important aim of the project is to build a user-friendly model. The officials
of Saxony and Brandenburg are used to working with water - quantity models, as
quantity management today is already controlled by such a model. Due to their
expertise what they expect from the Spree model can be clearly defined and expressed. The main objective ofa workshop in October 2001 will be to synchronize
the users' expectations with the scientists' products.
219
into contact with the air. This enabled the oxidation of iron sulphides, e.g. pyrite.
Its products, iron and sulphates, are washed into the open pits by returning
groundwater. The consequence is an acidification of the lake water down to pH 2.
This has to be avoided because the open pits are intended as lakes mainly for recreational use. Much research has been done to find ways to stop this process, but
up to now the only practicable way is to hinder the infiltration of groundwater into
the lakes. Therefore they have to be filled artificially with water from the River
Spree. The lake water will still be acid, but at a much more acceptable level.
The Upper River Spree passes very close to quarrying sites, both active and
closed down, so that, additionally, acidic groundwater infiltrates directly the river.
Once the lakes are filled, water from the river will still be led through the lakes to
dilute the acid water as much as possible. The water returning into the river will
therefore also be acidic. Until today it is unknown how much of the acidic water
the River Spree can take without creating further problems.
4 Objectives
The main objective of the joint task is to develop a water management tool for the
catchment area of the River Spree. The environmental offices of the federal states
of Saxony and Brandenburg have to manage the water quantity in the catchment
area of the River Spree in such a way as to find the optimum between the contradicting demands. The Spree model will be used as a decision - support system in
these cases. The objective is to predict the water quality until the year 2035, depending on the chosen water quantity management strategies.
The model user prefers to run the model within a couple of hours, as a variety
of management strategies for each hydrological situation will have to be analyzed.
Therefore, the calculation time has to be limited to a few hours at maximum. The
total running time is the main reason why no existing models, which are normally
of complex structure, could bee used in this case.
Another reason not to apply any existing water - quality model is the required
list of simulated parameters. Due to the influence of the lignite mining industry
and others, parameters such as iron, sulphate and pH value are offar higher importance to the total quality situation than in other catchment areas. Processes are taking place in completely different dimensions. Commercial models would have to
be enhanced in order to meet the requirements of the concerns of the research
area. The only way to comply with all requirements was to develop a new model
(Schlaeger and Kongeter 2001).
An important aim of the project is to build a user-friendly model. The officials
of Saxony and Brandenburg are used to working with water - quantity models, as
quantity management today is already controlled by such a model. Due to their
expertise what they expect from the Spree model can be clearly defined and expressed. The main objective ofa workshop in October 2001 will be to synchronize
the users' expectations with the scientists' products.