جستجوی مقالات مرتبط با کلیدواژه « vulnerability » در نشریات گروه « آب و خاک »

Today, human activities are one of the most important challenges in issues related to the quality of water resources, which is currently considered one of the management threats in the exploitation sector. This issue will require the identification and evaluation of water resources from different perspectives, of which the vulnerability of water resources is one. This study evaluates the vulnerability of water resources by combining two DRASTIC vulnerability indices in the aquifer sector and WRASTIC vulnerability index in the upland sector of Astana-Kuchsefahan region. In this study, after assessing the vulnerability with the relevant indicators, two methods of entropy and hierarchical analysis were used for scaling based on maximizing the correlation with nitrate concentration. The results showed that the most importance in both indices based on recalibrated weights include industrial use in the WRASTIC index and underground water depth in the DRASTIC index. The analysis of the calibration results showed that the correlation of nitrate with the DRASTIC vulnerability index using the AHP method was 0.61 and with the WRASTIC index was 0.58 using the Shannon entropy method. Also, the measurement results showed that the WRASTIC index ranges from 17 to 46 and the DRASTIC index ranges from 119 to 180. Based on the consolidated results in the western and eastern parts of the highlands, the level of vulnerability using the WRASTIC index is lower and there is a higher vulnerability in the western part of the aquifer compared to the eastern part.

The source of many qualitative and quantitative problems of water resources is the activities that are done in a watershed. Therefore, reviewing the planning strategies of watershed can lead to the reduction of these challenges therefore it is necessary to assess the effects of operating of these strategies before implementing them.

This research is carried out in the Hashtgerd basin is located in the central part of Alborz province. After making the semi distributed hydrological model (SWAT), this model has been developed to convert quantity and quality of surface water resources. For this purpose, the statistics of hydrometric stations Fashand, Dehsomeh and Najmabad and qualitative data of nitrate of the index station were calibrated and validated as control points. After model sensitivity analysis, its calibration process was conducted using SWAT-CUP software with SUFI2 algorithm and 500 iteration and the best values of selected parameters were obtained. Then, impact of implementing management scenarios are required such as modifying cropping pattern and improving irrigation methods to enhance the agricultural efficiency for improving agricultural state and reducing the contaminations. At last assessing the vulnerability of the Hastgerd aquifer using seven DRASTIC parameters by overlaying layers, ranking and weighing was assessed.

The results of the monthly surface runoff simulation were tested by Nash-Sutcliffe indicators and coefficient of determination. The results above 0.7 which showed that the simulation was done with good precision showed that simulation was done with proper precision(results over 0.7). The results of the Nitrate calibration and validation show that the NS was 0.83 and 0.7 and the R2 was estimated .87 and 0.89. These values indicate the proper performance of the model and approve high correlation between the observed and simulated data. After determining the vulnerability map of the Hashtgerd aquifer along the density of wells correcting the weights of the model layers, the central part of the plain is the most vulnerable.

Two management scenarios were modeled including the change in the cropping pattern and improvement of the irrigation efficiency to assess the quality and quantity variation in surface resource. It was indicated, by modifying the cropping pattern and reducing water exploitation, the amount of surface runoff was increased. However, the density of Nitrate was reduced by 5 to 20 percent in different months. With implementation of scenarios, the water consumption in the agriculture sector will be reduced from the 85.3 MCM to 59.8 MCM. The final vulnerability index of the aquifer varied between 44 to 90 by using DRASTIC method.

Aquifers, as one of the most vulnerable water sources, are exposed to various contaminants in different forms, which detecting and controlling pollution in these resources are more difficult and costly than surface water. The best way to prevent their contamination is to identify polluting sources and vulnerable areas, prepare vulnerable zoning maps and adopt appropriate management policies. In this study, the DRASTIC and GODS methods are used to assess the Khezri area. Khezri area is one of the sub-basins of Khaf-Petergan Playa Iran, based on the political divisions of the country, and located in the southern Khorasan province near Qayen city, between the longitudes of 35 58 to 17 59 east and latitudes 41 33 to 6 34. The results of the DRASTIC for this area showed that a small part of the area has very low vulnerability, a very wide area of the plain has low vulnerability (69.68%), and the northwest and west of this plain have medium, high and very high vulnerability. Sensitivity analysis is also done in this area with two methods of eliminating the parameter and single parameter. In the single parameter sensitivity analysis, the aquifer environment parameter has the most effective weight and the parameter of the topographic slope percentage has the least effective weight in calculating the vulnerability index. In the map zoned by both methods, the points with high vulnerability are in the area of Khezri city and steel factory.

Floods are one of the most damaging natural disasters in the world. So better understanding of the flood hazard phenomenon and its potential consequences is necessary. The present research is a part of the flood risk management approach based on the KULTURisk framework, in which vulnerability is examined as one of the flood risk components. The aim of the research is to assess the vulnerability of local communities exposed to the flood occurrence in the current conditions, and also to predict the effects of intervention scenarios to reduce it. Flood vulnerability assessment requires quantifying vulnerability components. In this research, the components, variables and indicators for the region existing conditions were selected based on the intended aim, region field observations and related literature review. The required data and information were collected using questionnaires and interviews with the local communities, statistical yearbooks, population and housing census data center, instructions and guidelines for the management system of statistics and hospital information, as well as referring to related executive organizations at the city and province levels. The statistical population includes local communities living in the 100-year flooding areas in a part of the Qarachai River in Ramian city (one of the tributaries of the Gorganroud River in the Golestan province). The reason for choosing this reach is the location of the villages in the vicinity of the river and the frequency of flood events that have occurred in the past years. The index values were normalized by classification scale and distance to reference methods and the weight of each index was determined by the Delphi method. The normalized index values were converted into spatial layers in the GIS environment. Then, a vulnerability map of the target area was prepared by combining the spatial layers of susceptibility, adaptation capacities and coping capacities variables. Based on the results, three intervention scenarios including early warning system establishment, risk governance intervention and risk spreading were selected in order to reduce the level of vulnerability in the face flooding for the study area. The degree of vulnerability of flood-affected areas in the study area for the current conditions was placed in the "highly vulnerable" class, while by applying intervention scenario under combined scenarios (including early warning system establishment, risk governance intervention and risk spreading), the vulnerability degree would change to "slightly vulnerable" level. The results of this research, is helpful for better understanding of the phenomenon of flooding and its potential consequences by the people and authorities of the Seyed Kalateh village. It also will facilitate the prioritization of measures appropriate to the region conditions in order to reduce vulnerability by increasing the capacity of adaptation and tolerance. Since, the effectiveness of the proposed measures such as creating an early warning system, intervention risk governance and risk spreading on reducing vulnerability and consequently reducing the amount of human and financial losses has been recognized, it is an important step in the direction of flood risk management at different scales. Moreover, the analysis shows the necessity of vulnerability assessment and adoption of specific policies at the local scale (the Seyed Kalateh village), while this issue is usually not considered in technical and financial planning of crisis management especially for flood risk management.

Groundwater is one of the most important water resources in many parts of Iran as well as in Sirjan plain. Although in comparison with surface waters, groundwaters are less vulnerable to pollution, their pollution abatement is much more difficult. It is thus necessary to protect them from being polluted. Additionally, in contrast with stream waters which are concentrated in linear areas across the world, groundwaters are present in vast areas. This means they are much more accessible and human beings are much more dependent on them. They are also present under terrains having different uses. That is, their protection against pollution and preparing their vulnerability maps is of utmost importance. There are different methods to determine the pollution potential of groundwater, the most widely used and the most comprehensive method is DRASTIC. DRASTIC is a model that considers the main hydrological and geological factors which potentially may impact aquifers. It considers seven relevant parameters which include depth to water table (D), recharge rate (R), aquifer material (A), soil characteristics (S), topographic slope (T), vadose zone impact (I), and aquifer,s hydraulic conductivity (C). The depth to the water table (D, in meters) is the distance from the land surface to the groundwater level, which means the distance the polluter must pass to reach groundwater. The net recharge (R, in mm per year) is the amount of infiltrated water that reaches the aquifer from the surface. The soil characteristics determine the ease with which a polluter can pass the soil layer toward groundwater. The probability of a surficial polluting agent reaching groundwater is inversely related to surface slope, which is expressed as T in DRASTIC. The material comprising the vadose zone plays an important role in blocking the movement of polluting agents to reach the water table. In DRASTIC, each parameter has devoted a rate of 1 (the least important) to 10 (the most important) which depends on its value. Subsequently, the DRASTIC index is determined using the weights considered for each of the seven parameters. Sirjan plain is one of the most developing plains in Iran which has many different land uses, including agriculture, urban areas, roads, and factories. The majority of these uses may pollute groundwater. It is, therefore, necessary to adapt the different land uses with groundwater vulnerability rates. So, the purpose of this article is to determine the groundwater pollution potential of this plain using the DRASTIC model.

In this study, the relevant seven parameters were first prepared. For preparing the D layer, the depths of the water table measured from monitoring wells across the plain were employed. The (R) layer was prepared using the data of rainfall infiltration, runoff infiltration, and infiltration from residential and agricultural areas. For preparing the (A) layer, 70 geological logs of the area were used. The (S) layer was prepared according to field studies and geological logs. The digital elevation model (DEM) was used to prepare the (T) layer. The (I) layer was prepared using the geological logs of the area. Finally, the (C) layer was prepared by dividing the transmissibility values of the aquifer by its thicknesses. All maps were rated according to and combined to calculate the DRASTIC index (DI). DI values were validated according to nitrate concentrations, and sensitivity analysis was undertaken by omitting the layers successively.

The relevant DRASRIC layers are given in Figures 2 to 8. In the depth rating map (Fig 2 ), the majority of the surface belongs to rate 1. This means that due to high water-level depths, this parameter has lowered pollution potential. In the recharge rating map (Fig 3), the major part of the plain is green (rate 1), meaning very low levels of recharge and a low role in pollution. The aquifer material map (Fig 4) is mainly covered by 5, 6, and 7 rates. The soil rating map (Fig 5 ) indicates that the 7, 8, and 9 rates cover the major parts. This means a rather high pollution potential share of this parameter. In the topographic slope rating map (Fig 6) the 9 and 10 rates cover vast surfaces at the west and south, and the 4-7 rate values of the vadose zone rating map (Fig 7) represent the average contribution from this parameter. The aquifer's hydraulic conductivity map (Fig 8) indicates a rather wide range contribution of this parameter. DI values of the study area range from 60 to 128, representing rather medium vulnerability. The higher vulnerability values are mostly observed in the western part, where recharge from agriculture is high, the topographic slope is gentle, and the water level is rather high. Low and medium values of DI are mostly observed at the north center and east. In a qualified vulnerability map comparatively low, medium, and high vulnerability values are separated. The high values mostly belong to residential and agricultural areas, which are at the risk of nitrate, pesticide, saltwater, detergent, and heavy metal risk factors.

The DRASTIC index values of the Sirjan alluvial aquifer range from 60 to 128, meaning low- to high vulnerability values. The most vulnerable locations mainly include residential and agricultural areas which may deliver considerable amounts of nitrate, detergents, pesticides, heavy metals, and dissolved salts to the aquifer. It is, therefore, necessary to reduce the pollution potential in these areas by such means as reducing pesticide use, using green agricultural practices, and collecting and treating sewage from residential areas. Considering the high water level dropdowns in this plain, which means decreasing groundwater resources, it is necessary to abate the pollution risk of these limited resources via such means as adapting land use with vulnerability at every location.

Population growth, urbanization, and land use change have increased disastrous floods. Iran is also among the countries at high risk of floods. The latest examples of flood damage are the devastating floods of the spring of 2019 with significant mortality and financial losses in more than ten provinces of the country. The purpose of this study is to prepare an urban flood risk map of District 4 City Shiraz. The vulnerability of the region was made using PROMETHEE Ⅱ and COPRAS multi-criteria decision-making models and urban flood hazard zones were prepared by partial least squares regression (PLSR) and ridge regression (RR) models and a risk map was obtained by multiplying the vulnerability and hazard in ArcGIS software. The highest percentage of the study area in the PROMETHEE Ⅱ and COPRAS models belongs to the moderate class of vulnerability. The evaluation of the vulnerability models using Boolean logic and RMSE and MAPE statistics, showed that the COPRAS model provided better results than the PROMETHEE model. The results of partial least square regression (PLSR) and ridge regression (RR) models in flood risk modeling were analyzed by the Taylor diagram, which showed the superiority of the ridge regression (RR) model and the accuracy of this model in preparing urban flood hazard maps. The risk map of the study area indicated that 34% of the area (973 ha) is in the range of high and very high flood risk.

One of the approaches to equilibrium assessment is the use of quantitative and qualitative indicators that can be a good tool. In this study, in order to evaluate the equilibrium scenarios in Hashtgerd aquifer, two indicators of intrinsic vulnerability of the aquifer and quantitative stability index of the aquifer were used. Five scenarios were defined based on the groundwater resources balancing scheme in the region and simulated using the MODFLOW numerical model. Equilibrium was calculated by combining three indicators of reliability, vulnerability and desirability of groundwater system stability index in different scenarios. The simulation results and application of different scenarios showed that by reducing the water withdrawal by 15 percent, the highest level of stability is created in the aquifer system and the system stability rate increases from 55 percent to 87 percent. The extent of changes in the aquifer stability index as a distribution in the observation wells also indicates that the middle part of the aquifer has the highest status of improving the stability index. This region, with its high density of exploitation wells, is most affected by the reduction of aquifer withdrawals. The results obtained from the aquifer stability index, considering the spatial distribution, show the feasibility of implementing different scenarios. On the other hand, due to the importance of development and the use of vulnerability indicators, the drastic index was analyzed at the regional level. The results showed that the upstream part of the aquifer has the highest level of vulnerability due to hydrogeological characteristics and the level of vulnerability has decreased in the direction of groundwater flow.

Unsustainable development without considering regional planning can create adverse environmental effects, especially in karst water resources of a region from a qualitative point of view. Accordingly, in this study, a combination of two methods for determining spring vulnerability and qualitative zoning by MDHT method was used. This study was performed for three springs downstream of Seymareh Dam for a period of 5 years. The results showed that the value of vulnerability index in S1 spring was higher than the other two springs and the value was 150.4. Analysis of the results showed that the degree of vulnerability was an inverse function of spring discharge. By increasing the amount of discharge, the vulnerability index decreases. Considering the choice of MDHT method for qualitative zoning of the spring and the role of flow rate in determining the zoning scenario, the highest flow rate was related to S3 spring. The value of obtained MDHT index was also higher than the other two sources and the value of 417 has been calculated. The lowest flow rate was related to S1 spring and the MDHT index value was 14.75. The highest level is related to spring S1 and the lowest level is related to springs S2 and S3. The results show that the karst network of springs in the region is vulnerable, which affects the quality of these resources and sensitive areas of the region to develop exploitation are strongly associated with the risk of pollution.

Groundwater in arid regions such as Iran plays a very large role in drinking water supply and agriculture. One of the threats to the future of groundwater exploitation, could be the contamination of these resources by harmful substances. At present, about 60% of the water consumption of Varamin plain region and the total volume of water consumption in the drinking sector is provided from groundwater sources. One of the best ways to prevent groundwater pollution is to identify vulnerable aquifer areas. The SINTACS model has been used to assess the vulnerability of the Varamin plain aquifer. This method consists of seven parameters that after combining the parameters, the vulnerability index map is obtained. The index of this method varies between 92 and 168.Results show that the north of the plain is very vulnerable and vulnerability is low in the south-eastern parts of Jalilabad village and downstream areas of the plain, while the rest of the plain has moderate vulnerability. A three-dimensional numerical model was used to evaluate the results of the model and the model was validated for a period of one year. The accuracy of the constructed model was evaluated as appropriate. In this model, nitrate contaminant was considered as an aquifer contaminant. In order to validate the inherent and special vulnerability of the SINTACS model, the nitrate output of the model was used, The correlation square of the results was about 65%, which shows a good agreement between the two models even thogh the numerical model is considered as micro- model compared to SINTACS one. Considering the role of the aquifer of Varamin plain in supplying the required water of the region, the quantitative and qualitative protection of this aquifer is a necessary and strongly recommonded. Also, in order to reduce the nitrate ion concentration in the study area, long-term solutions such as improving the agricultural structure and cultivation pattern of the area and constructing a collection network and wastewater treatment plant are proposed.

Water, as a major limiting factor in production, plays an important role in determining the type of agricultural activities in Iran. The occurrence of droughts in recent decades have also threatened these activities. Today, one of the most effective responses and strategies for agricultural drought risk management is to identify vulnerable areas and determine the optimal pattern of low-water cultivation. Therefore, the aim of this study is spatial analysis of agricultural drought vulnerability and introduce a pattern of low-water cultivation and compatible with arid areas in Pishkuh watershed in Yazd province. In this research, first the dominant garden species in the study area were identified and after calculating their water requirements, a map of the agricultural drought vulnerability in the study area was prepared. The results showed that the southern to southwestern of study area, including the villages of Sanich, Darreh Shir, Darreh Sir, etc., have the highest vulnerability to drought compared to other areas. Therefore, it is recommended to be cultivated garden species with the least water requirement such as almond and Grapes with water needs of 753 and 798 mm during the growing period, respectively. Also Results showed that the central, eastern, and northwestern of study area, including Islamieh, Navab, Nasrabad villages and etc., have a moderate and relatively low vulnerability. In addition, it is recommended to plant the species with moderate-water needs such as pomegranate and apricot. Therefore, changing and modifying the cultivation pattern, such as reducing the planting areas with high water requirements, developing species with low water needs, and increasing water efficiency, is one of the most necessary activities for managing agricultural drought risk.

Sewage collection network is one of the largest and most valuable infrastructure assets. Therefore, managing the wastewater collection network faces many challenges. Unfortunately, due to the extent of the damaged wastewater collection network and time and budget constraints, it is not possible in practice to treat and eliminate all wastewater collection system damages at the same time. So, this issue requires management activities in the form of vulnerability rating, to develop a maintenance program for sewage collection system maintenance. The present study evaluated and ranked the vulnerability of the sewerage network implemented in a part of District 5 of Tehran Municipality using a combination of Analytic Hierarchy Process (AHP) and GIS technique. AHP is one of the most efficient multi-criteria decision-making techniques, in this method, the factors are compared with each other in pairs and the highest weight is given to the layer that has the maximum effect on goal setting. In this regard, according to the opinion of experts and literature review, all types of possible damage to the sewage collection network at three levels of manhole, pipeline and branch were investigated and classified. In order to determine the relative importance of the defects, a questionnaire was prepared and distributed amongst experts working in the field of design and maintenance of sewage systems. Using AHP method, pairwise comparison between the relevant factors was performed and the relative weight of each criterion was calculated. After calculating the inconsistency ratio and confirming the meaningfulness of the judgement matrices of effective factors, the final weight of each criterion was applied to the corresponding layers to prepare the zoning map of the area. Next, judgement matrices were transferred to ArcGIS software and raster output was generated from them. The raster layers of different factors in ArcGIS software were homogenized and then combined using Fuzzy Membership method. In fact, the ultimate goal of the GIS technique used in this study was to obtaine the final overlap of all factors affecting the vulnerability of the sewage collection network (at two levels of manhole and pipeline clogging) and provide a zoning map of damages in the study network. It is important to note that the transformed raster maps for each of the effective factors have different units that must be scaled to the fuzzy membership method. As a result, all values scaled between 0 and 1 range. In general, each number in this range indicates the strength of membership in a set, based on a specific fuzzy algorithm. Next, the Fuzzy Membership command was run to obtain fuzzy the classified raster, from the Spatial Analyst Tools toolbox and the Overlay menu. Thus, fuzzy raster of quantitative criteria affecting the vulnerability of the sewage collection network was obtained. Weighted Overlay method was used to correctly apply the resulted weights and present the final model in ArcGIS. Thus, the fuzzy raster was added to the Spatial Analyst Tools toolbox and the Overlay menu, using the Weighted Sum command. Then, the aggregation of the obtained weights revealed the total weight of each of the target factors. Finally, the vulnerability zoning map of the sewage collection network was prepared in two levels of manhole and pipeline. According to the results, the probability of failure of the implemented manholes was very low and more than 70% of the manholes were classified in the category of low and very low damage. One of the possible reasons for this could be the young age and the principled implementation of the sewage collection network. The final overlap of the factors and sub-criteria affecting the vulnerability of the sewerage network indicated that the probability of destruction of pipelines was very low. More than 74% of the sewerage collection pipeline implemented in the case study area was classified in the category of low and medium damage. The results showed that only 30 wastewater transfer pipelines (about 7% of the whole network) were in critical conditions that should be given more attention. It could be considered that the small number of critical pipelines was due to the short life of the implemented pipelines. Based on the results, among the three target factors (manhole, pipeline and branch), the highest vulnerability of the sewerage collection network was related to the pipeline blockage. Also, the defects of the operational defects in all three levels of manhole, pipeline and branch clogging was the most affecting factor and have the highest impact.

Nitrate is one of the most common contaminants that originates from fertilizers, pesticides or domestic and industrial wastewater. This non-point source contaminant exposes the Salmas plain aquifer to groundwater pollution due to extensive agricultural activity. Therefore, it is necessary to assess the contamination risk of aquifer to high nitrate concentration and identify the high-risk areas in this aquifer. In this research, the contamination risk of Salmas plain aquifer was investigated using DRASTIC-L framework and groundwater velocity. For this purpose, after constructing of DRASTIC-L framework, the weights of eight layers of the framework optimized by genetic algorithm to obtain the aquifer vulnerability map to nitrate contaminant. Finally, the contamination risk map to nitrate was achieved from multiplying the aquifer vulnerability and groundwater velocity. The results showed that against to the eastern and central parts of the aquifer, the contamination risk of the aquifer is high in the western part of the aquifer.

This study aimed to investigate the vulnerability of Sistan plain to fluctuations and Water Scarcity in Hirmand River using the vulnerability framework, by applying the resilience approach. The socioeconomic and biophysical components presented in this framework were embedded in a set of subsystems of the System Dynamics (SD) model. According to this, four levels of reference resilience were defined based on the annual flow from the Hirmand River, and the system attributes of concern were identified under the existing structure until 2050. Then, the proposed strategies to the socio-economic structure of the model were applied under two critical conditions of water scarcity and fluctuations of the river flow. The values associated to the system attributes of concern of the two mentioned conditions were compared with the reference resilience levels. The results showed the efficiency of the policy option in reducing water scarcity and the importance of the environmental impacts of the biophysical component. For example, the two modes of water scarcity and water inflow fluctuations had the revenues of 9490 and 5100 billion IRR (annual income according to the base price of 2011), but they had the same population and residentchr('39')s utility, which was related to receiving 117 and 600 MCM of the environmental demand, respectively. Management, development and continuous support of the industrial sector can provide a "Success to the Successful" archetype for the socio-economic section of Sistan Plain.

One way to balance the environment is to study and manage aquifer vulnerabilities. In order to decide and manage the aquifer, the need for planning to identify vulnerable areas is very important. Several methods and indicators to assess the vulnerability of the aquifer are presented in each of these indicators is based on a set of factors used. In this study, 5 vulnerability indicators have been used in the coastal region to investigate and compare these methods. The characteristics of DRASTIC, SINTACS, SI, GALDIT and GODS were investigated to assess the sensitivity of the aquifer inherently. The results of these 5 indicators were different according to the nature of each of them and in order to increase the accuracy of the results and practical use of these results in coastal areas, weight and rankings were performed using hierarchical and entropy analysis method. For this purpose, the correlation between the vulnerability index concentrations of TDS, nitrate and chloride and weights of each indicator was calibrated. Sensitivity analysis of various parameters in vulnerability indicators showed that GALDIT index reflects this sensitivity in the results, considering the effect of sea salt water progress. Depth parameter to static level in other indicators and distance parameter from the sea is a sensitive and important criterion in GALDIT index and after model calibration, it was found that 30% of aquifers are exposed to the saline fronts of sea water infiltration.

Groundwater resources,as one of the most important resources of water supply, have been faced with the qualitative decline and increasing the concentration of pollutants in addition to a quantitive problems in recent years. According to the importance of the role of water supply quality in exploitation, recognizing the aquifer and factors affecting it is very important. This study was conducted to investigate the movement of pollutants with the view of assessing aquifer vulnerability in one of the branches of Zanjan River. Accordingly, two types of intrinsic and special vulnerability in the region were investigated by two methods of drastic and HPI. The results of vulnerability index show that the soil of region is effective in decreasing the concentration of heavy metals under study (lead, chromium, nickel, cobalt, zinc) and the concentration reduces in the direction of groundwater flow. The results of vulnerability index showed that the Drastic index is more than 80% in the medium to low and low ranking and the HPI index of the basin with an average of 30.3 is in the low risk, however, this basin has the potential to develop pollution. In order to determine the direction of pollution and the role of alluvial in the area MODPATH numerical model was used to simulate under the influence of the advection process in order to determine the direction of pollutants movement and the role of alluvium of the region. The numerical simulation of the region was carried out for three years after modeling and calibrating the MODFLOW model. Based on the results, the wells located along the groundwater and surface water flow path in the center of the basin have longer length compared to the wells that are around and far from the center of the basin. Based on the results, different patterns can be used such as creating barriers to modify and reduce the amount of pollutants transfer in this basin and other basins leading to Zanjan River.

The occurrence of climate change and its impact on surface water and groundwater resources, along with inappropriate management of water resources have led to an increase in the social and environmental vulnerability of river systems. Assessing the vulnerability of river basins, especially in developing countries such as Iran is essential and is considered as one of the main priorities of the water resources planners for the sustainable management of these resources and for the formulating of policies consistent with the regional conditions. In this line, this paper focuses on the assessment of the vulnerability of the Jarahi River Basin.

The study area of this research, the Jarahi River Basin, with an area of about 24000 square kilometers is located in southwest of Iran with a population of about 870000 people. In this research, the River Basin Vulnerability (RBV) method was used to assess the vulnerability of the Jarahi River Basin. This method examines the vulnerability of ecosystem and human simultaneously and consists of a total of six main indicators including ‘governance’, ‘economic status’, ‘social condition’, ‘environment’, ‘water stress’, and ‘natural hazards’ indicators. In this method, data are evaluated quantitatively. The combination of these indicators is based on a raster summation algorithm which can be carried out in the ArcGIS platform.

The anlysis shows that the vulnerability of the Jarahi River Basin corresponding to each of the indicators of governance, enconomic status, social condition, environment, hazards and water stress are 0.76, 0.41, 0.061, 0.43, 0.44 and 0. 84, respectively. The results exhibit that the Jarahi River Basin is severely threatened by natural hazards, and in particular, the flood hazard threatens all parts of the river basin. It is also exposed to high water stress. The highest water stress (0.76) associated with Shadegan sub-basin that is located in the southern part of the basin. In addition, Saiddon sub basin has the lowest literacy rate among the sub basin of the Jarahi River Basin with the rate of 79%. A significant part of the Shadeghan sub-basin exhibits considerable environmental impacts, interpreted as a discernible sign of human footprints in the area.

Generally, in the Jarahi River Basin, the vulnerability of three indicators, namely "governance", "water stress", and "natural hazards"are quite significant. In particular, flood assessment analysis shows that almost all the river basin is highly susceptible to flood hazard. Also, seismic hazard threatens a considerable portion of Behbahan and Takht-E Deraz sub-basins. The results regarding the water stress show that almost half of the basin (mostly Shadegan sub-basin) suffers from high water stress. Through controlling corruption, improving Iran’s political stability status and reducing the government fragility index, an improvement in the governence indicator can be achieved. Concerning the water stress indicator, given that the excessive use of water in the agriculture sector is mostly responsible for the high vulnerability state, changing the current land-use and accordingly the cropping pattern in the Jarahi River Basin will potentially have a positive impact on water stress indicator.Moreover, regarding the natural hazards, given the high potential of drought, flood, and earthquake occurrences in the research area,it is possible to somewhat reduce the incurred damages caused by these phenomena in the river basin by means of paying due attention to knowledge, awareness, planning and efficient management.