فهرست مطالب saeed rasi nezami

Land use/land cover (LULC) change, strongly affects surface water characteristics, especially in urban watersheds. The aim of this study was to determine LULC in the Samian Watershed and assessing its relationship with water quality parameters. In this study, LULC maps was obtained by ENVI software in four periods (1992 to 2016). Then, 9 water quality parameters at five river gauge stations were selected for further analysis. The Mann-Kendall test was performed to examine the trends in water quality parameters and Pearson test was used to assess the correlation between quality parameters and land uses. According to the results, rangeland decreased by 9.75%, irrigated agriculture increased by 8.45%, residential increased by 1.42% and rainfed agriculture increased by 3.29% compared to the first period. Average of TDS and EC in the study periods in Samian and Gilandeh stations, has been increased. The correlation analysis using Pearson test between quality data and LULC also shows that the EC, Ca, Cl, SO4, Mg and Na pameters of had a significant relationship with increasing residential, irrigated and rainfed land uses.

Water resource planning in different world countries is based on the potential surface resource availability. Land use changes, especially in watersheds that include cities and population centers, strongly affect the quantity of water. This study aims to determine land use/land cover changes in the Samian watershed, Ardabil. Also, investigating the relationship between land use changes and the amount of surface water in this watershed was explored.

In this study, ENVI software obtained land use for four time periods from 1993 to 2017. In order to investigate the quantitative changes of water, 5 hydrometric stations and 32 rain gauge stations within the watershed were selected, and the runoff coefficient of these stations was obtained based on the recorded data in river gauge stations. In the next step, ANOVA and Tukey test were exerted to determine the significance of changes in the mean runoff coefficient.

In the studied years, rangelands have decreased considerably by 9.75%. Also, irrigated agriculture had the highest increase, with 8.45%. Residential areas had increased in the study period by 1.42% compared to the first period. Rainfed agriculture has also increased by 3.29% in the study area.

In all studied hydrometric stations except Nir station, the changes in runoff coefficient were significant. In Samian, Aladizgheh, Atashghah, and Ghilande stations, the changes in runoff coefficient have decreased, which means a decrease in river discharge during the research period.

Innovation: 

The results can be used in the quantitative analysis of the relationship between land use change and surface runoff coefficient changes. Also, based on the reduction of natural lands, it is possible to predict the increasing intensity of runoff and flooding. In addition, land use planning and management and knowledge of the amount, intensity, and spatial changes of runoff production potential are prerequisites for planning runoff control.

Rivers are valuable sources of water supply for various purposes. These sources are seriously exposed to quality degradation due to the entry of various contaminants. Therefore, proper monitoring and quality management of these resources could be very important. In the present study, the quality of the Balikhlou river in Ardabil province, northwest of Iran, was investigated by surveying the trend of changes in river quality parameters, as well as water quality indices. In this study, after collecting the available data, by determining the trend of changes in quality parameters, the suitability of the studied river water quality for drinking and irrigation purposes was determined. The results indicated that there is an inverse relationship between changes in river discharge rate and the concentration of qualitative parameters. Therefore, it was found that salinity-containing pollution sources enter the river upstream of the desired station. Besides, the results of water quality indices showed that the water quality of the studied river is very poor for drinking (WQI>75). In addition, the results of water quality assessment for irrigation use based on SAR, KI, and SSP indices were generally considered inappropriate (SAR>26, KI>1, SSP>50), EC was often permissible (750<EC<2250), and MH was appropriate (MH<50). Our study highlights the importance of river water quality studies over time and thus can lead to better management of these valuable resources.

Zoning of flood hazards in a dam catchment plays an essential role in water resources planning and management. In the present study, nine lithogenic and anthropogenic parameters including slope, elevation, curve number, distance to river, rainfall, geology, soil texture, Normalized Difference Vegetation Index (NDVI) and land use are used to achieve a flood hazard map in downstream of Sabalan dam basin in Ardabil province, Iran. After categorizing the criteria, the layers were weighted by two multi-criteria decision making (MCDM) methods including analytic hierarchy process (AHP), and analytic network process (ANP). The results showed that among the factors affecting flood formation in the study basin by AHP method were the elevation and slope factors with the weights of 0.31 and 0.18 respectively, have the highest effect; however, curve number and distance to river factors with the weights of 0.04 and 0.02 have the lowest effect. Similarly, in the ANP method, the elevation and slope factors with the weights of 0.30 and 0.21 respectively, have the highest effect and the curve number and distance to river factors with the weights of 0.02 and 0.006 have the lowest impact on flood hazard potential in the study area. The results obtained in this study can be useful in achieving sustainable management of water resources.

The use of optimization-simulation tools is one of the effective approaches that can play a significant role in analyzing water resources management scenarios. In this study, using MODSIM water resources planning model, the effect of different management scenarios in water scarcity conditions on water allocation planning in Balekhlichai river catchment and also the water level of Ardabil plain aquifer was investigated. Calibration and validation of the model were performed by considering the surface flow hydrograph of the basin outlet and the aquifer hydrograph using the data of the statistical period 2000-2014. Then the return flow coefficients were estimated by trial and error. The values of root mean square error and Nash-Sutcliffe efficiency coefficient in the calibration and validation period indicate the good performance of the model in simulating surface and groundwater flow and water balance components of catchment. After ensuring the accuracy of the model simulation, various management scenarios including population growth scenario (S), irrigation efficiency change (S1) and cultivation pattern and irrigation efficiency changes (S2) were examined. The results showed that under scenarios S, S1 and S2, the groundwater level drop will be equal to 8.41, 3.36 and 2.31 meters, respectively. Also, under scenarios S, S1 and S2, the percentage of agricultural demand supply in the Yamchi irrigation network from the reservoir will be equal to 38, 43 and 48 percent, respectively. Therefore, by applying water resources management scenarios, it is possible to prevent a sharp drop in the water level of the Ardabil plain aquifer in the future years and take an effective step in balancing groundwater.

In recent years, the growing population and the need to supply water for domestic, and health, and agriculture sectors have led to the establishment of industrial centers in developing countries. The onset of drought in most countries has challenged surface water, groundwater, dams, and reservoirs. Iran is among those countries, which is located in a dry and semi-arid region.  These factors made managers and decision-makers in this field make appropriate rules and regulations for the use of limited water resources. In this paper, the Vensim dynamic model was applied to properly exploit the Yamchi Dam water and groundwater resources in the Ardabil plain in Iran and allocate these resources in the agriculture, industry, and drinking sectors. By defining different scenarios, it was found that pressurized irrigation and changing the crop pattern scenarios are the most appropriate options for water management in the Yamchi basin. In this scenario, known as G in the model, 62% of the network lands are moved from traditional flood to pressurized irrigation with an irrigation efficiency of 60%. Accordingly, the reliability of the agricultural and drinking water supply will reach 92 and 99%, respectively. Meanwhile, due to saving the water resources, the water infiltration caused by irrigation will be greatly reduced, and the land swamping will be prevented.

Experiment design is believed to be an important part of investigating an engineering phenomenon for characterizing and optimizing the process. In this study, the Taguchi method (TM) reduced the number of experiments and was used to analyze the results of an artificial neural network (ANN) and find the optimal combination of the relevant parameters in the ANN. Accordingly, the phenomenon of the local scour depth around the bridge during flood events was considered as a case study. The study results indicated that TM could reduce the number of experiments compared to the previous original study and the full factorial method by 28% and 67%, respectively. According to TM, the flow intensity at the hydrograph peak was the most effective parameter providing the optimal state (minimum scour depth). Additionally, an ANN with three hidden layers and the main parameters, including several neurons in the first and second hidden layers, training function, and transfer function, was introduced. Adjusting the input parameters of the ANN, TM led to the emergence of networks with a reasonable correlation coefficient of R= 0.952. Finally, the results demonstrated that the transfer function had the most significant effect on the results of the ANN.

The spread of urbanization in floodplains as well as increase of industrial and agricultural activities in river discharges may lead to water pollution by physical، chemical and biological pollutants. One of the major concerns in monitoring the water resources system is indentifying major quality parameters and determining a relationship between physical and chemical parameters. This is important because the physical parameters are usually related to the natural characteristics of the river basin، while chemical parameters are associated with human-made pollution resources. Thus، if there is a high correlation between these two groups of parameters، it could be concluded that the source of both parameters are identical. However، to achieve this goal، costly and time consuming instrumental techniques and intensive laboratory efforts might be required. To determine the major quality parameters that cause water pollution in Karkheh River، statistical principal components analysis (PCA) method was employed. Moreover، canonical correlation analysis (CCA) was used to find the relationships between physical and chemical parameters. In this study، discharge rate (Q)، turbidity (Turb)، temperature (T)، dissolved oxygen (DO)، total suspended solids (TSS) and electrical conductivity (EC) were selected as representative parameters for the physical characteristics of the river water quality. In addition، pH، 5-day biological oxygen demand (BOD5)، chemical oxygen demand (COD)، total phosphorous (TP) and total nitrogen (TN) were chosen as representatives of the river chemical attributes. These two groups of quality parameters were measured along the Karkheh River in 18 monitoring stations from March 2006 to March 2007. Results of PCA analysis indicated that all the selected chemical and physical parameters of Karkheh River were of high importance. Further investigations indicated that in CCA analysis the first three canonical correlations were 0. 896، 0. 848 and 0. 593، respectively، suggesting that turbidity، DO and TSS were three dominant physical parameters in all the canonical variables، whilst BOD5، COD، TP and TN were highly scored among the chemical parameters. According to the CCA results، it can be implied that human activities are the source of the physical and chemical parameters of the river. The utilized statistical methods in this study can be used as an appropriate decision support system for water sector managers regarding water quality management of the river basin when large complex water quality data are involved.