Investigate Spatial and Temporal Changes of Precipitation Hydro-Chemical Parameters (Case study: North Khorasan Province)

To investigate the hydro-chemical composition of local precipitation and its relationship with pollutant sources can be advantageous in understanding the hydrological cycle and the mechanism of groundwater recharge. The current paper selected ۳۲ stations at different altitudes and suitable spatial distribution and rainfall sampling was performed in a one-year period. Analysis of precipitation samples shows that the electrical conductivity in the center and south of the province and during low rainy seasons is more than the borders of the province and rainy months. The pH value is the lowest during the rainy and cold months and the highest in the summer. In urban regions, the pH was slightly lower than that of rural regions. The predominant type is the samples of calcium carbonate precipitation, and according to Piper and Steve's map, almost all ions show relatively the same behavior at different times, and weak acids predominate over strong acids.