Application of GIS for determination of groundwater quality suitable in crops influenced by irrigation water in the Damghan region of Iran

Abstract

In order to evaluate the quality of groundwater in Damghan plain for irrigation purposes, 199 surveyed wells 
with GPS data used to produce the map. The features that generally had considered for evaluation of the 
suitable quality of groundwater for irrigation are salinity, water infiltration rate, and specific ion toxicity. The 
SAR , ions Ca2+ ,Mg2+ , Na+ , K+ , CO3 2-, HCO3-– , SO4
2- , Cl-, electrical conductivity (EC), total dissolved solids 
(TDS), pH were analyze as the evaluation indexes. The EC map indicates the presence of about 0.04% of the 
study area; groundwater lie in good range (none degree of restriction on use) 61.38% slight to moderate and 
38.58% severe for irrigation purposes. The suitable zones for ECw are in the central and northwestern and 
portion of south of the study area (61.42%). The quality of groundwater for the sodium hazard on infiltration is in 
98.9% of study area none degree of restriction on use and in 0.6% slight to moderate and 0.5% severe. The 
suitable zones for infiltration have no degree of restriction on use in majority of the study area. The maps result 
of crops yield potential as influenced by irrigation water salinity (ECw) indicates that crops barley>wheat > 
Alfalfa respectively have yield potential more against ECW in study area (99.42,92.3 and 0.23%). The results of 
thematic maps of sodiumw, choloridw were overlaid with maps of sodiumplant, choloridplant showed that the 
crops yield potential of barley and wheat. Alfalfa in all the study area is 100%.