The aim of the study was to determine the contamination transport condition with sediment in the Widawa River, which inflows to the Odra River below Wrocław city. The transport simulations have been performed by means of HEC-RAS model, which was calibrated. Study and geochemical analyses indicate that pollutions are cumulated mainly in sediment of grain size, less than 0,20 mm. It was stated that the main sources of contaminations occurring in the Widawa River bottoms are: superficial run-off, municipal and industrial wastes. Sediment bed quality from the Widawa River in selected cross-sections has been analyzed. Samples of suspended load were collected and divided into eight fractions, for which the phosphorus concentration P was calculated. Deposit particles less than 0,20 mm contained most phosphorus, i.e. 73% (3,52 ppm), and particles greater than 0,20 mm about 27% (1,30 ppm) for the whole sample volume. Relationship between the phosphorus concentration P and the sediment grain size was determined. Analysis showed that the initiation of contamination-sediment suspension in the Widawa River is well described by Engelund criterion. Simulations of the migration of pollutions together with deposits in the Widawa River showed that during average flow discharge, the transport intensity of pollution was equal 2 mg/s, and sediments 6 kg/s. In the present work the water quality of the Widawa River has been also presented.

In the projects of protection of soil-water environment there is a need to combine and process large amount of information from various disciplines to estimate parameters of phenomena and to determine the range and time table of necessary undertakings.

Due to complex assessment of processes taking place in aquifers, mathematical modeling is the best tool supporting evaluation off pollution in the ground water environment. It is also an effective method of forecasting the risk associated with the harmful impact of objects polluting grounds and grounds waters.

Significant application of mathematical modeling is the use for the enlargement of information gathered in the process of recognition and assessment of condition that prevail in soil-water environment. Results of modeling, if appropriately presented, could be an important element of decision support system in environmental management.

This paper describes procedures for developing an environmental remediation decision support system by linking CADD and GIS software with the hydro geological flow and transport models.