Simulation for non-point source pollution based on QUAL2E in the Jinghe River, Shaanxi Province, China

Wang, J., Huo, A., Hu, A., Zhang, X., & Wu, Y. (March-April, 2017). Simulation for non-point source pollution based on QUAL2E in the Jinghe River, Shaanxi Province, China. Water Technology and Sciences (in Spanish), 8(2), 117-126. Water pollution in river basins is significantly influenced by point-source and non-point-source pollutants. Compared with point-source pollutants, the identification and quantification of non-point-source pollutants are critical but difficult issues in water environmental pollution studies. The Jinghe River is one of the main tributaries of the Weihe River. However, the non-point-source pollution of this river is not well understood. In order to analyze the sources of pointand non-point loads to river water, the river water quality model QUAL2E and Principal Component Analysis (PCA) & Factor Analysis (FA) were applied simultaneously to calculate the point- and non-point-source loads of ammonia nitrogen and nitrate nitrogen, respectively, in dry and wet seasons from 2002 to 2007. The results show that NO3 - -N can be associated with point-source pollution, such as domestic sewage in dry seasons, but non-point-source pollution generated by precipitation in wet seasons. NH4 +-N can be associated with point-source pollution throughout the year. The methods applied in this research provide reliable results on non-point-source pollution caused by storm runoff

Hydrodynamic Behaviors and Geochemical Evolution of Groundwater for Irrigation in Yaoba Oasis, China

The Yaoba Oasis is an irrigated cropland entirely dependent on groundwater; previous investigations (1980–2015) revealed an over-abstraction of groundwater and deteriorating groundwater quality. For further exploring the hydrodynamic behaviors and geochemical processes of groundwater during the irrigation season, groundwater samples were collected and analyzed using different techniques including classical statistics, correlation analysis, Piper diagrams, and Gibbs diagrams. The results indicated that Na+, K+, SO42− and Cl− were the main ions in groundwater, which were significantly correlated with TDS. The water–rock interaction is manifested by the precipitation of calcite and dolomite and the dissolution of rock salt and gypsum as an increase in TDS related to evaporation. In addition, the increasing complexity of hydrochemical type is caused by the rapid variation of hydrodynamic regime, irrigation and evaporation, which are subjected to the constraints of salty water intrusion from the desert salty lake and infiltration of irrigation return flow. Existing wells should limit overexploitation to halt the decline in groundwater levels and cut down irrigation water to reduce the risk of groundwater contamination and restore ecological balance in desert oasis