Nutrient and heavy metal emissions into the river system of Odra - results and comparison of models
The nutrient and heavy metal emissions by point and diffuse sources were estimated for 45 sub catchments of the Odra basin for the period 1993-1997 by means of the Models MONERIS, MODEST and NIIRS. For nitrogen total emissions of 124 ktN/a were esti- mated for the Odra basin. 64% of these emissions were caused by diffuse sources (mainly groundwater and tile drainage). For Phosphorus the emission was 12.8 ktP/a, with a contri- bution of diffuse sources to this sum of 38%. The comparison of calculated and observed loads shows that the mean deviation for the investigated sub catchments of Odra is 22% for nitrogen and 32% for phosphorus. The spatial resolution of the emission calculations allows the identification of regional hot spots and the derivation of specific regional measures to reduce the emissions into the Odra. For the heavy metals emissions of 10,8 t/a (Cd), 175 t/a (Cu), 113 t/a (Pb) and 1190 t/a (Zn) were estimated. A comparison of different models for the nitrogen inputs by groundwater shows that with the present knowledge of processes and data base a conceptual model achieve the same results than a detailed mechanistic ap- proach.
Download Link