Water Quality Assessment and Spatial-Temporal Distribution of Nitrogen in the Tianzhuang Reservoir

The water quality of the Tianzhuang Reservoir and its inflows were assessed with the single factor index method to identify the main pollution factor of the reservoir. The spatial-temporal distribution of nitrogen were analyzed to gross judge the main pollution sources. The results indicate NO₃^--N accounts for more than 65% of the TN in the Tianzhuang Reservoir. The water quality cannot meet V grade of the Environmental Quality Standards for surface Water for NH₃-N and TN exceeding the respective standard. The NO₃^--N concentration of the reservoir equals to that of the inflows which affect by non-point source pollution (NPS) from agricultural areas. Therefore NPS is the main pollution source for NO₃^--N of the reservoir. In addition, the bottom sediments are the important pollution source for NH₃-N. The results can aid in identifying the key pollutants and their sources of the reservoir.