Urban development and pollution of groundwater resources (Case study: Hamadan–Bahar Plain)

Population growth and the increase of water demand in the different sectors of agriculture, drinking water, industry, health, groundwater resources have led to a lot of pressure. This issue along with severe and prolonged droughts has created conditions for the country, particularly in arid and hyper arid areas, whereby it has encountered serious challenges in the field of water quantity and quality. In this study, the qualitative changes in the trend of drought and water resources in the Hamadan-Bahar plain, one of the most important agricultural centres in Iran, has been considered. Twenty-three wells were sampled across the plain, on September 2015 and, in order to evaluate the strategic parameters in the study, standard methods were used. All anions and cations in the water along with fluoride, nitrate and nitrite were measured. The results showed a reduction of groundwater level decline by an average of 1 metre per year and the parameters measured indicated adverse changes in the quality of underground water sources. The maximum measured nitrite and nitrate, respectively, was 74.8 and 0.41 mg/L for the area. About 27% of the samples collected were close to the national standard of 43 milligrams per litre, while the average was critical at the border; however, the average total for nitrates was 24.2 mg/L. The amount of fluoride in most cases was lower than the international standard. In some cases the amount of sulfate flowing through the city’s sewage system was also standard. Considering the results, it can be concluded that the only fundamental method for preventing dangerous consequences of falling water table levels and reducing the quantity and quality of underground water resources is to ensure correct and legal water consumption to avoid the uncontrolled withdrawal of groundwater.