# Example of the numerical model at Chotebor, Czech Republic

The numeric modelling was the background for the risk assessment analysis which had its aim in complex assessment of risk factors and it should have set new target of the remediation and its length. To solve the existing ecological problem we did the modelling for the initial state and for the current state of remediation. The planar model of the steady groundwater flow was done by means of the BEFLOW software system. This system uses the BEM to solve the groundwater flow partial differential equation. Transport of pollution dissolves in groundwater was solved by the random walk particle method together with the BEM. We had two alternatives in modelling of the transport of dissolved pollutant without any sorption and with a linear sorption. The sorption is ineffective at places where the rock skeleton is fully contaminated. The sorption is still effective at places distant from the pollution source. First we set up a hydraulic model of the domain and then we verified it using the known initial state of groundwater flow. This was followed by the modelling of transport of pollution dissolved in groundwater for the initial state. The last stage was the modelling of pollution transport for the current status of remediation.