Analysis of factors affecting the ecological status of the large water bodies on the basis of monitoring and integrated 3D models

The paper presents water monitoring methods used to determine and predict the ecological status of large water bodies based on calibrated 3D water quality models. State monitoring system of quality of water was discussed and critically reviewed. Mobile measurements technique to collect vast number of measuring points across the large water body during one day cruise to make maps of pollutants distributions was described. Maps of water quality parameters show dynamic changes of spatial distributions of pollutants both in time and along the length of the lake which proves that one point measurements cannot be representative for the large water body. Critical evaluation of calibration principles and accuracy of the most frequently used water quality models, WASP and GEMSS are presented. On the basis of CFD calculations, close correlation between water quality and hydrodynamics in large water bodies regarding the physicochemical aspects and biological production was proved. Neglecting the effect of hydrodynamic on eutrophication process introduce large element of uncertainty in determination of nutrients flow in the large water bodies. An example of scenarios for improving the ecological potential of dam reservoirs to obtain significant reduction of selected nutrients concentration in the lake is discussed