Mahrookh Ghazayi, Nazfar Aghazadeh, Ehsan Ghaleh, Elhameh Ebaddyy,
Volume 0, Issue 0 (3-1921)
Abstract
Lack of surface water resources has led to uncontrolled abstraction of groundwater in many parts of the world and severe depletion of groundwater table levels. With the increasing population, the extraction of these resources has increased and these natural reserves are facing a serious threat. The present study was conducted to monitor the groundwater level using satellite images and the relationship that it can have with land use. In order to achieve the desired result, first the relevant satellite images were taken, and the necessary pre-processing was applied on each of them. Among the important tools, the use of object-oriented method, land use classification map was extracted for both years and Land use change map was extracted for a period of 15 years (2000-2015). Finally, in order to monitor the groundwater level map, the groundwater level map of the study area for both years was extracted by Gaussian method, which was the most accurate method. The results showed that there is a strong and significant relationship between land use and groundwater level. Areas of the study area that have higher vegetation have lower groundwater levels than other areas. It follows the earth and also causes water to flow from high potential points to these points. Also, irrigated agricultural use had the highest average drop in water level compared to other uses, which indicates the excessive use of groundwater to irrigate irrigated agricultural products in the study area.The results also showed that the conventional kriging method with Gaussian variance is more accurate than the other methods used to estimate the depth of groundwater water table in both statistical periods. Conveying by conventional kriging method showed that the groundwater level in most parts of the plain has decreased during the study period. The maximum drop is 40 meters and the average is 15 meters.
Dr Maryam Bayatvarkeshi, Ms Rojin Fasihi,
Volume 18, Issue 48 (3-2018)
Abstract
Modeling provides the studying of groundwater managers as an efficient method with the lowest cost. The purpose of this study was comparison of the numerical model, neural intelligent and geostatistical in groundwater table changes modeling. The information of Hamedan – Bahar aquifer was studied as one of the most important water sources in Hamedan province. In this study, MODFLOW numerical code in GMS software, artificial neural network (ANN) and neural – fuzzy (CANFIS) method in NeuroSolution software, wavelet-neural method in MATLAB software and geostatistical method in ArcGIS software were used. The results showed that the accuracy of methods in estimation of the groundwater table with the lowest Normal Root Mean Square Error (NRMSE) include Wavelet-ANN, CANFIS, geostatistical, ANN and numerical model, respectively. The NRMSE value in Wavelet-ANN method as optimization method was 0.11 % and in numerical model was 2.2 %. Also the correlation coefficients were 0.998 and 0.904, respectively. So application of neural combination models, specially, wavelet theory in estimated the groundwater table is most suitable than geostatistical and numerical model. Moreover, in the neural intelligent models were applied latitude, longitude and altitude as available variables in input models. The zoning results of groundwater table indicated that the decreased trend of groundwater table was from the west to the east of aquifer which was in line with the hydraulic gradient.
