علیرضا متولی

Human activities have significantly contributed to environmental destruction, necessitating the assessment of land use changes to better understand and manage land resources. Land use plays a crucial role in balancing hydrology, economy, and the environment. By evaluating the intensity and trends of land use, we gain insight into the processes within the ecosystem. This study focuses on analyzing land use/cover changes in the Ramian watershed, Golestan province. Satellite images from Landsat were utilized to create land use maps in 1991, 2006, and 2021 using the Support Vector Machine (SVM) algorithm and ENVI software. The accuracy of these maps was assessed using the kappa coefficient and overall accuracy. The results indicate acceptable accuracy, with kappa coefficients of 0.74, 0.79, and 0.87, and overall accuracies of 81%, 86%, and 91% for the respective study years. Noteworthy changes occurred in dry farming, forest, irrigated agriculture, orchard, pasture, and residential areas, with percentages of 19.92%, -4.50%, 42.28%, 571.5%, -8.87%, and 107.3% respectively over the 30-year study period. These findings underscore the impact of human activities on land use degradation in the Ramian watershed landscape and can provide valuable insights for designing practical models to land management.

Determining the potential of mineral springs is one of the important and essential issues in water resources management. In this study, the potential map of the spring for the management and planning of groundwater resources was performed using statistical models of frequency ratio (FR) and weight of evidence (WOE) in the Vazrood Watershed. For this purpose, 57 springs were identified randomly in the calibration (34) and validation (23) phases. In the implementation of both models, the effective factors in spring potential were used include: slope percentage and aspect, hypsometry, plan and profile, geology, land use, topographic wetness index, distance from fault, fault density, drainge density, distance from the river and the road. The results showed that the accuracy of the FR model was 84.4% and the accuracy of the WOE model was 77.2%. These results indicate a very good accuracy of these two models in determining the potential areas of springs in the Vazrood Watershed. According to the results, the accuracy of the FR model is also higher than the WOE model. Finally, 39.7% and 34.9% of Vazroud watershed in high and very high classes in terms of spring potential are in two models of WOE and FR models, respectively. Finally, the potential maps of the springs can be used to provide the basic infrastructure to clean the springs from human damage and the entry of investors to build a drinking water spring factory and ultimately the prosperity of the local economy of the Watershed residents of Vazroud.

Groundwater vulnerability is due to the inherent vulnerability and characteristics of the occurrence of contaminating sources and human-induced pollution. Sixty four quality measuring wells, 20 observation wells and more than 28000 operating wells were sampled in order to provide vulnerability maps for 2004 and 2014. The essential factors of the inherent vulnerability included hydraulic conductivity, aquifer type, distance from the coast, and aquifer thickness. Additional factors of specific vulnerability including well density, decline of groundwater level, relative impact of seawater intrusion, condition of saltwater up-coning and hydraulic gradient were also used. The results indicated that the quality of groundwater resources had declined from 2004 to 2014 according to salinity criteria such as electrical indicated by an increase in conductivity (EC), sodium absorption ratio (SAR) and total dissolved solids (TDS). The land use factor was also used to prepare modified vulnerability maps for the year through 2004-2014. The results indicated that while the irrigated area had decreased by 8 percent during this period, the level in high-vulnerability areas had increased, which may be surmised that an increase discharge rate and double-cropping had caused degradation of the groundwater. The results showed that the mean correlation coefficient of vulnerability to salinity classes with salinity criteria such as EC, TDS and SAR had improved in 2004 from 0.65 to 0.9, and in 2014 from 0.78 to 0.87. Duo to the complexity of qualitative modeling, solute transport and groundwater salinity, the modified vulnerability maps is a good tool to predict the impending groundwater salinization.

Changes and fluctuations of precipitation are one of the most important climate change outcomes in the world. The changes in surface water flow and hydrological cycle are directly affected. Therefore, recognition of fluctuations behavior and its governing patterns in a catchment area plays a very important role in optimal management of catchment areas. Therefore, in this research, we have tried to identify the trends of fluctuations patterns of rainfall and also the type of precipitation trend in the Golpayegan catchment area. For this purpose, daily rainfall data of precipitation stations near the Golpayegan saline wetland were used. For trend analysis, linear regression and Mann-Kendall method were used and for identify the rainfall prevailing cycles, Spectrum analysis technique was used. The results of trend analysis showed that in all studied stations, rainfall had a significant decrease. The highest trend is a significant decrease of 23 mm for the Golpayegan station. The results of spectral analysis also indicate that the short-term cycles of 2 to 5 years are in most of the studied stations. Most scientists have attributed this cycle as a result of El Niño - Southern Oscillation (ENSO) and Quasi-biennial oscillation (QBO).