Modeling Management and Climate Change Impacts on Water Pollution by Heavy Metals in the Nizhnekamskoe Reservoir Watershed

Abstract

The semi-distributed physically based ECOMAG-HM model was applied to simulate the cycling of the heavy metals (HM) Cu, Zn, and Mn, and to identify spatial and temporal patterns of heavy metal pollution in water bodies of a large river catchment of the Nizhnekamskoe reservoir (NKR) in Russia. The main river of the catchment is the Belaya River, one of the most polluted rivers in the Southern Urals. The model was tested against long-term data on hydrological and hydrochemical monitoring of water bodies. It is shown that the pollution of rivers is formed mainly due to diffuse wash-off of metals into rivers from the soil-ground layer. Numerical experiments to assess the impact of water economic activities on river pollution were carried out by modeling scenarios of changes in the amount of metal discharged with wastewater, a disaster with a salvo discharge of pollutants, and the exclusion of anthropogenic impact on the catchment to assess self-purification of the basin. Modeling of chemical runoff in accordance with the delta-change climatic scenario showed that significant changes in water quality characteristics should not be expected in the near future up to 2050.