TY - JOUR ID - 67989 TI - Spatial and Temporal Variations of Nitrate Concentration in Groundwater (Case Study: Watershed Silveh) JO - Journal of Range and Watershed Managment JA - JRWM LA - en SN - 5044-2008 AU - Asadi Nalivan, Omid AU - Ghiasi, Seid Saeid AU - Feiznia, Sadat AU - sagghazade, Narges AD - gorgan university AD - Tehran university AD - university of Tehran AD - ardakan university Y1 - 2018 PY - 2018 VL - 71 IS - 2 SP - 307 EP - 319 KW - Spatial and Temporal Variations KW - Anthropogenic activity KW - Kriging KW - Groundwater quality KW - Nitrate DO - 10.22059/jrwm.2018.23042. N2 - At present, Groundwater contamination by nitrate, serves as one of the most important environmental issues. In respect to various land uses of Silveh basin, its ground water quality parameters might vary spatially and temporally. For this, ground water samples taken from 145 points were evaluated. After determining nitrate spatial variations by varyogram, different methods involved distance inverse method and geo-statistics methods of radial estimator approaches, local estimator, ordinary kriging, simple kriging and global kriging were evaluated using GIS software and nitrate spatial distribution map were prepared in two time intervals (pre and post-harvest). Criteria based on the Root Mean Squared Error(RMSE), ordinary kriging method has the lowest error, and the accuracy considerably. Spatial distribution of nitrate in area groundwater indicated that there was high concentration of nitrate in land uses of agriculture and arid area. Of course, presence of shale-stone causes nitrate releases, intensifying issues. Comparison of nitrate samples concentration with national and international standards suggested that 1.38%(2 Point) of all samples have been nitrate-contaminated before harvesting, while 11.03%(16 Point) of them have been contaminated after harvesting. UR - https://jrwm.ut.ac.ir/article_67989.html L1 - https://jrwm.ut.ac.ir/article_67989_217effa897f12eb1b4fc4fe5f0c2dbec.pdf ER -