Document Type : Research Article
. Faculty of Natural Resources, university of Tehran
Faculty of Natural Resources, university of Tehran
Faculty of Natural Resources, Ferdowsi University of Mashhad
This research was conducted in order to study the effect of climate and geology factors on groundwater sources in Mahvelat plain. In order to study the groundwater quality and quantity considering groundwater resources including wells and qanats; using groundwater surface, Electric Conduction (EC) and the Total Density Solution (TDS), the maps of groundwater surface fluctuation and quality parameters were prepared by geostatistical methods in ArcGIS 9.3 software environment. At second phase for determination the causes of changes in groundwater quality and quantity, factors such as reduced rainfall and droughts (Standardized Precipitation Index (SPI) was used), geology, sedimentology (The geology maps were provided), stick up saltwater front from adjacent desert area were studied. The results zoning maps of groundwater quality and quantity showed that water level has been decreased in most part of the study area. Studding hydro-chemical parameters showed that the highest concentration of the mentioned parameters was at output of area in the west and southwest. Changing procedure of water quality was rising and toward salinity until the end of the period. The results of water quantitative and qualitative parameters showed that increase of exploitation wells in different ways, such as increasing land for gardening (especially pistachio), rainfall decrease and drought have caused decline in groundwater level and that followed with progress of saltwater fronts from neighboring deserts in the south and west of the studied area through rivers and cables affected and decreases its quality. However, these zones in terms of qualitatively causes influence decrease and feeding of ground water level because have fine grained sediments and the presence of abundant salt and evaporite deposits. If this trend continues, in near future in addition to the development and exacerbation of adverse environmental effect we will see severe damage to agriculture because of lack of serious and practical activities for decrease indiscriminate harvesting and lack of water table balance.