Identification sources of groundwater Salinization in Daier-Abdan region

Groundwater salinization has become a crucial environmental problem
worldwide and is considered the most widespread form of groundwater
contamination. It has been established that intensive agricultural
activities, usually, increase the risk of groundwater quality degradation
through high groundwater pumping rates. In fact, the uncontrolled
groundwater extraction causes a modification of natural flow systems and
induces seawater intrusion from the coast and causes the groundwater
quality deterioration. The Abdan - Dayyer aquifer is located in the Sorth-
West of Iran. The dry season is pronounced and this aggravates the
situation, given that the highest water demand usually coincides with the
drought period (dry weather conditions). The principal aim of this study
is to identifying the main processes that occur in the groundwater system.
In order to achieve this aim, chemical parameters were measured, such as
electrical conductivity, pH, temperature, anions and cations
concentrations and isotope composition of water samples. The analytical
results obtained in the hydrochemistry study were interpreted using ion
correlations with chloride, iso-concentration maps and isotope variation
in conjunction with calculations of the mixing ratios and the saturation
indexes. The results indicate the existence of various salinization
processes such as: evaporation, dissolution of gypsum, dolomite and
calcite dispersed through the reservoir rock; inverse cation exchange;
intensive agricultural practices that produce effluents that infiltrate to the
saturated zone; and sea-water and saltwater intrusion, enhanced by
excessive withdrawal of groundwater. Hydrogeologically, the study area
could be clustered into three areas, Abdan, Jamrak and Lombedan.
Salinization in Lombedan, Abdan and Jamrak area is caused by sea water
intrusion, movement of saline evaporated water and evaporation from
water table, respectively. Several practical methods are proposed to
control the quality of groundwater in the study area.