Determination of origin of major ions in groundwaters of Astaneh-Koochesfehan area
Subject Areas :مسعود Eshaghpour 1 , محمد Manshori 2
1 - دانشجوی کارشناسی ارشد دانشگاه آزاد اسلامی، واحد علوم و تحقیقات تهران
2 - استادیار گروه علوم و مهندسی آب، دانشگاه آزاد اسلامی، واحد علوم و تحقیقات تهران
Keywords: Groundwater, Hydrogeochemistry, Astaneh – Koochesfehan, Sefidrood River,
Abstract :
Sefidrood river watershed is located in 9 provinces of Iran consist of 3 subwatershed of Ghezelozan,Shahrood and endparts of Sefidrood. In order to determination of origin of major ions in aquifer ofAstaneh-Koochesfehan study area that is located in central parts of Gilan province and end parts ofSefidrood River, data from 25 deep and shallow quality wells with maximum depth of 150m during 11period from September 2003 to September 2008 and 4 hydrometry station on 3 mentionedsubwatersheds was analyzed. Pole Astaneh and Beyne Rahe Roodbar are located in end parts ofSefidrood subwatershed and Shahrood and Gilavan are located on Shahrood and Ghezelozan riversubaequentely.The study area is located between longitudes of 370000-430000 m and latitudes of4099000-4150000 m in UTM system in zone of 39N. Astaneh Ashrafiyyeh is the largest city in thestudy area. Lithology of the study area consist of deltaic deposits and Sefidrood River alluvialsspreading from Emamzadeh Hashem to Sefidrood Delta in Caspian sea coast as a fan with a head inthe south and a long side in the north. Well samples are classified as natural waters and classified asC3S1 when Sefidrood samples in Gilevan Station as C4S2 and 3 other stations are classified as C3S1.Relatively high EC and TDS decreasing water taste quality. Relatively low quality of Sefidrood Riverwater and better quality of Disam River water influences groundwaters. There is no evidence of seawater intrusion in the groundwaters. Water type is Calcium and magnesium bicarbonate. Using linearregression equation and determination coefficient between anions and cations results that bicarbonateis originated from dissolution of limestone formations in the study area or Great Sefidrood watershade,chloride is interred in the groundwaters resulting from dissolution of evaporation deposits in theGhezelozan watershade and sulfate from dissolution of evaporation deposits in Ghezelozanwatershade and leaching of potash fertilizers from soil