TY - JOUR T1 - Simulation of Nitrate Transport in Groundwater: Lenjanat Plain, Isfahan TT - شبیه‌سازی انتقال نیترات در آب زیرزمینی: دشت لنجانات اصفهان JF - jsci JO - jsci VL - 16 IS - 42 UR - http://jsci.khu.ac.ir/article-1-2059-en.html Y1 - 2015 SP - 89 EP - 106 KW - Groundwater flow modeling KW - Nitrate transport simulation KW - MT3DMS code KW - Lenjanat aquifer N2 - The present study aimed at identifying the nitrate transport in the groundwater of Lenjanat plain, Isfahan. Nitrate concentrations were measured seasonally and groundwater flow was modeled for nitrate transport simulation using MODFLOW and MT3DMS codes. The nitrate concentrations were compared with the human and livestock drinking water and irrigation water standards. The results show that nitrate concentrations are higher than the guidelines limits in groundwaters. The flow modeling reveals that the groundwater flow system of the study aquifer has been influenced by the aquifer hydrogeological characteristics. The falling watertable and reduce aquifer storage are due to the anthropogenic stresses on flow system. The transport model calibration and sensitivity analysis shows that nitrate leaching from agricultural land, first–order irreversible rate reaction, effective porosity and precipitation are the major factors affecting the entry and retention of nitrate in Lenjanat groundwater. Denitrification rate in the aquifer has been decreased due to high concentration of dissolved oxygen in groundwater and low extent of organic carbon. Half-life of nitrate in Lenjanat aquifer is more than 2.5 years. Nitrate transport in the aquifer is mainly by convection. Considering the calculated mass with transport model, the nitrogen leaching to groundwater of study area is 108 kg N ha-1 yr-1. M3 ER -