نشریه جغرافیا و مخاطرات محیطی
پیاپی 6 (تابستان 1392)

Atmospheric hazards are defined as any atmospheric event، which adversely affect or may adversely affect human life، property، or other aspects of the environment. The events can influence all aspects of human life. The main purpose of this research is zonation of atmospheric hazards in the northeast of Iran including North Khorasan، Khorasan Razavi and South Khorasan. In order to achieve the purpose، the spatial distribution of all atmospheric hazards، which occur over the area، has been investigated in terms of frequency and intensity. Study Area: Study Area is located in the northeastern of Iran with an area of 300000 Km between N30 21 to N38 17 latitudes and E55 28 to E61 14 Longitudes. The Study Area concludes three following provinces in the country: Khorasan Shomali، Khorasan Razavi and Khorasan Jonobi which have been separated from great Khorasan during the past decade. Extending the region from low latitudes to high latitudes and affected by different climatic systems resulted occurrence of a set climatic hazards throughout the study area. This paper is focused on atmospheric hazards zoning in the area using geographic information Systems (GIS). In order to identify the spatial distribution of each atmospheric hazard، the meteorological data of 17 weather stations in North Khorasan، Khorasan Razavi and South Khorasan is used for a 38-year (1971-2008) period. In this basis، 13 variables including precipitation، mean temperature، maximum temperature، minimum temperature، wind direction and intensity، visibility and weather conditions in terms of daily and monthly scales were used to investigate the frequency and the intensity of atmospheric hazards. In the first step، 13 major atmospheric hazards، including drought، heavy and extreme precipitation events، heavy snowfall، hail، thunderstorm، blizzard، fog، dust storm، dusty days، heat wave، frost and wind-chill events were identified in the scope of northeast of Iran. To make a general zonation map for atmospheric hazards، we analyzed each atmospheric hazard by a distinct method with regards to the characteristics of each hazard. Using the distinct methods، we determined the frequency and intensity of each hazard. Then، the Geography Information System (GIS) is applied to make a spatial analysis of the events and spatial distribution map is produced for each hazard by using ArcGIS tools. In the next step، all atmospheric hazards have been contained in three categories، with regards to their similarities and differences. Therefore، all atmospheric hazards categorized in temperature-based hazards، precipitation-related hazards and weather hazards related to visibility. As a final step، we combined all atmospheric hazards to make a general zonation map for the Northeast of Iran. The results indicate that the freezing and wind-chill events are the most frequent hazards in the northeast of Iran. It is found that، while the temperature-based hazards are increasing from north to south، the spatial distribution of precipitation-related hazards is showing an inverse mode، so that they are increasing from south to north. In contrast، the spatial distribution of atmospheric hazards related to visibility is more zonal than meridian direction. Therefore، they are showing a decrease from east to west. The final zonation map of atmospheric hazards which produced by combination of all elements confirm that the more hazards in northern part of the study area can be caused by the high frequency of eastward movement of extra-tropical systems as well as high mountains arrangement in northeastern part of Iran. The research showed that the north and northeastern parts of the study area hit by more atmospheric hazards and has the highest frequency of atmospheric hazards in regards to spatial analysis of the events. Therefore، we can conclude that the large parts of northern and northeastern Khorasan should be considered the most risky area over the whole domain. In contrast، the western and southern parts of Khorasan are the lowest risky areas as well. The results also indicate that the wind-chill event is the dominant atmospheric hazard over the entire domain in terms of frequency.

Dust storm is one of the most important natural phenomena and a kind of severe natural disaster that begins and diffuses under the influence of atmospheric systems. It occurs frequently in desert lands and their surrounding areas in arid and semi-arid regions. The main factors influencing amount of dust in the air are precipitation، vegetation cover، and wind velocity and particle size of soil in source of dust. Over the past decades، Middle East dust storms have caused many problems for the residents of South and South West regions of Iran. Now it is going to change into the main persistent environmental problem in Iran and the Middle East region. The Middle East dust has great impacts on quality of the inhabitant’s lives، visibility and transportation، micro-climate، ecosystem، communication systems and consequent crisis such as، eco – social and environmental problems in the west and south west of Iran. Different aspects of this phenomenon in the Middle East have already been considered by researchers. The aims of this study are to (1) understand the possible source (s) of West of Iran Dust storms and (2) determine the geochemical، mineralogical، trace metals and microbiological characteristics of dust particles in the west of Iran. Study Area: The study area from which sampling was performed، include two provinces of Kermanshah (45. 24-48. 30 E and 33. 36-35. 15 N)، and Khuzestan (47. 42°–50. 39° N and 29. 58°–32. 58°N) which are located close to the Iranian border with Iraq in western Iran. This region comprises 38 cities and a population of more than 6،000،000 people. Topographic elevations in these provinces vary between 0 m (in beaches) and 3701 m (Menar Mountain in Khuzestan province). Fig. 1. The Study Area In this study، five severe dust storms in the west and southwest of Iran have been selected. The air sampling was performed in Ahvaz and Mahshar Cities in Khuzestan province، Kermanshah and Qasre-Shirin cities in Kermanshah province. Dust samples were collected to obtain PST by using the high-volume Air (HVA) samplers (Anderson and TCR models) and the fiberglass filters used to get particles. The flow rate of the HVA sampler was 1 M3/min. Also، for some times the sampling was performed by using Low volume Air (LVA) sampler. After the calibration of air sampler، the particles were got from sampling stations، which were located at urban areas in these cities on the height of 2 meter above the ground. The sampler was run continuously for a period of 24 h. Then، the HYSPLIT (HYbrid Single-Particle Lagrangian Integrated Trajectory) model is applied by using a backward trajectory approach in the study periods. The OMI imagery aerosol Index is used to determine the main sources of dust storm. The mineralogy، Sample elemental analyses، toxic trace elements analysis، Microorganisms Analysis of airborne dust samples were analyzed by XRD، XRF، Atomic Absorption and culture-based assays respectively. The outputs of HYSPLIT model and aerosol index from OMI imagery show that main sources of DS1 are the area between the west bank of Euphrates and east bank of Tigris in middle of Iraq، deserts lands in south east of Iraq and north east of Arabian Peninsula. In DS2، the main sources of dust are south and southeast of Syrian Desert، an area between Euphrates and Tigris، Nafud desert in north of Arabian Peninsula، and the coastal region in east of Arabian Peninsula. The main sources of dust in DS3 are South of Syrian desert، North of Arabian Peninsula (Nafud desert)، middle and south of Iraq. The dust sources in DS4 are Syrian Desert، the area between the west bank of Euphrates and east bank of Tigris، deserts lands in south of Iraq and for DS5 are Syrian Desert، desert lands in west of Iraq، the area between Euphrates and Tigris in middle and south of Iraq. The XRD analysis show that in all samples، quartz، calcite، albeit، muscovite، clinochlore and dolomite are common minerals. But other minerals such as gypsum، orthoclase، actinolite and palygorskite are present in some samples. XRF analyses of dust samples show that chemical compositions are SiO2 (34. 82%)، CaO (20. 48)، Al2O3 (8. 44%)، Fe2O3 (4. 36%) and MgO (4. 22%). Based on Atomic Absorption analysis، the average concentrations of heavy metals include Zn، Pb، Cd، Cu، Ni and Co are 472. 2، 109. 2، 10. 4، 52. 0، 111. 2 and 21. 0 PPM respectively. Ambient airborne dust microorganisms including the six bacteria species belonging to the genus Bacillus، Staphylococcus، Escherichia coli، Klebsiella، Pseudomonas and Enterobacter were found in dust samples. Also four fungi species isolated were Aspergillus، Rhizopus، mucor and Penicillium، that is common in environment. The outputs of HYSPLIT model and aerosol index from OMI imagery show that the main sources of airborne dusts for western Iran are dry lake beds and rivers، alluvial deposits and desert lands in Iraq especially the area between the west bank of Euphrates and east bank of Tigris and Hur-Al-Azim lagoon، east، northeast and southeast of Arabian Peninsula، east of Syria and secondary sources of dust storm in the west of Iran with low level quantity are desert land on Africa and Khuzestan province in Iran. The results of XRD analyses show that the main mineral loads are Quartz، Calcite، Gypsum، Albeit، Muscovite، Clinochlore and Dolomite. XRF analyses of dust samples show that the main chemical compositions are SiO2، CaO، Al2O3، Fe2O3 and MgO. Based on Atomic Absorption analysis the mean of heavy metal in dust storm is more than standard level. The microorganism analysis shows that the dust particles are contaminated with bacteria and fungi.

Identifying and preparing the aquifer zoning map of vulnerable areas، where the pollutants from surface water can infiltrate and spread into groundwater system، is an important management tool for preventing groundwater resource contamination. One of the most important vulnerable aquatic resources against the contamination is the aquifer. The purpose of this research is making the vulnerability map of the region and also detecting the regions with the highest amount of ground water contamination characters in the study area. Regarding to the importance of groundwater resources and its uses for different purposes such as drinking، agriculture and industry، we do the research and also study on the aquifer vulnerability. Also، protecting the region is necessary in developing optimal management of ground water resources. Study Area: Neishaboor plain، with an area of 3351/38 square kilometers، is one part of the aquatic basin of the central desert. The plain is located in the southern mountains of Binalood situated in northeastern part of central desert and its climate is mid-dry. The plain is located in the longitude of to eastern hemisphere and the latitude of to northern hemisphere. The highest height of Neishaboor Plain is 3200 m above the sea level over Binalood Mountains and the lowest point is 1050 m above the sea level in the exterior part of the plain. The rainfall is reported to be 292 mm as an average for the plain area. In this research، we have used different information including topographical maps or numerical topographical maps with 1:25000 scale، geometrical maps with 1:100000 scale، soil map، meteorological statistics، hydrology groundwater level، the result of pumping test، digging logarithm and observational well. We also utilized the wells and their data. The statistics of geographical studies maps and water consumption are all included in the research based on khorasan Razavi water stock company. Seven factors or characters that are measurable by the hydrological system are determined in this method. These factors included groundwater depth، net recharge، aquifer media، soil type، topography، impact of vadose zone and the hydraulic conductivity. These characters have numerically been estimated، so a special rate from 1 to 10 is specified to each factor relating the potential contaminants. Regarding to the layers in DRASTIC model and their special weight، the weight overlapping function was used by the Raster calculator menu in ArcGIS software to combine and compare the layers and integrate the data. The final map of the aquifer in comparison to the contamination was categorized into 5 boundaries or ranges، including extremely low vulnerability، low vulnerability، medium vulnerability، high vulnerability and extremely high vulnerability. One of the flaws noticed in DRASTIC model is that the categorizing and parameter evaluation is fairly expertized and the model should be calibrated by the distribution concentration of natural contaminants such as Nitrate، which mainly leads to special vulnerability of the aquifer. In this research، we have used the data related to Nitrate concentration driven from 57 samples of ground water wells to estimate the model again. Regarding to the zoning map، we found that nearly 23. 55 percent of the studied Region is located in the lowest vulnerability range، 17. 16 percent is located in the low vulnerability range، 19. 21 percent is located in the average vulnerability range، 28. 72 percent is located in high vulnerability range and finally 11. 36 percent is located in extremely high vulnerability range. The results show that the highest vulnerability potential range is high in the southern and western parts of the plain while the northern areas demonstrate the lowest potential. Comparing and contrasting the nitrate ion on the final map of DRASTIC model، it was concluded that areas with the highest nitrate ion concentrations are located in extremely high contaminate force range، emphasizing the precision and accuracy of the model.

The gravel extraction from the bottom of rivers constitutes an important source of aggregate for the construction of buildings، roads and other structures. The problems of fluvial erosion generated by these activities can affect properties and human works located near the river، and have become a severe problem in many regions of the world. The environmental costs of instream gravel extraction have generally not been factored into production costs، making instream sources more economically attractive than alternatives such as dry terrace mines، quarries or distant sources such as reservoir deltas. Gravel extraction can have both immediate and long-term consequences for channel stability. Changes to channel morphology are initiated through the lowering of the riverbed during extraction. As geomorphically effective sediment transporting events are infrequent in many gravel-bed rivers، instream mining activities may operate for several years without obvious effects upstream or downstream. However، responses may be manifest during high flows many years later. Study area: This paper examines the significance of within-channel gravel extraction on the morphometery of the River Lavij in northern Alborz. The study site at Khashpel Park is 2 km in length، and is located in the lower River Lvaij catchment in Nour Township، Mazandaran province. The altitude of the Lavij catchment varies from a maximum of 3359 m to 90 m on the valley floor. Mean annual rainfall in the catchment is around 650 mm. Mean daily discharge is 1. 7 m3 s−1 with a maximum mean daily discharge of 175 m3 s−1. The River Lavij is a gravel-bed channel dominated by cobble size material in the study reaches. The upper study area reaches to an altitude ranging between 120 m and 90 m with a mean slope of 0. 02m/m. In this study different types of data have been collected: (a) hydrological data، (b) channel morphometric data concerning the time evolution of the longitudinal profile، cross section and planform (c) bed grain size distributions of the study reach. The discharge records at the Aghozketi gauging station and discharge-area relationship are appropriate for the study reach. Regional catchment area-discharge plots are produced for a range of flood recurrence intervals (2، 5، 10، 50، 100، 200 years). Study area divided into two reaches. The first reach A has been mined before 2008 and the reach B has been mining to present. The data of reach A was surveyed in 2012. Then a comparison is made between the river character (longitudinal bed profiles، cross section and planform) of the intact reach and the reach A. Information on the recent evolution of the river character was collected from surveys made along the reach B at scale 1:1000 between 2008 and 2011. The grain size distribution of the gravel surface was obtained from Wolman pebble counts sampling of bed. An estimate of annual sediment delivery from the catchment to study reach calculated using an empirical regression equation of river suspended load. Then، we calculated gravel extraction on the fluvial sediment balance by comparing the extracted yield with an estimate of the catchment sediment yield. Long Profile: a general tendency towards incision four main changes observed in reach A. The changes in bed elevation were locally greater than 6. 5 m، 3. 3 m and 2. 5 m below river’s normal slope. Three drops were built in order to limit regressive erosion، reduce channel slope، and dissipate fluvial energy. The average river slope is greatly decreased from 0. 02 m/m to 0. 003 m/m between drop1 and drop 2. Local slopes increased to 0. 027 m/m between drop 2 and drop 3. The average river slope shows low changes in reach B، except reach 3. Cross section: the average river width shows a 10 m change between 2008 and 2011 in reach B. The bankfull depth increased up to 0. 5 m in this period. A decrease occurs in amount of stream power in both reach A and reach B. This apparent decreasing trend in stream power is not surprising because we observed a decrease in slope and increase in width. Planform: Channel planform analysis has revealed that both the reaches A and B are changed. The straight planform formed where the river has been artificially transformed in a series of steps and Gradient is steepened as flow follows a shorter path. Braided pattern has observed in reaches A2 and A3 that river gradient decreased. In reach B، river pattern has been straight or meandering. Sediment: the sediment average size in upper reach is 32 mm and it decreased in lower reach (B and A to 25 mm and 8 mm، respectively). A sediment budget by comparing the volume of sediment supplied from the catchment، which an estimate of that released during extraction. The volume extracted unallowable have estimated 80000 m3. Gravel extraction in study reach has changed the slope، width، depth، stream power، planform، and sediment size of channel. Comparing to reference conditions، reach A river altered irreversibly direct human disturbance and a wholesale shift in the geomorphic unit structure، planform، and bed material texture، so that the river has operated in a fundamentally different manner to its former state. In reach B، river altered reversibly direct human disturbance. Channel geomorphic analysis indicated that management interventions، such as Drop، only delay morphological adjustment.

Climate in the south of the Caspian Sea is very different from other parts of Iran. The existence of the Caspian Sea، complex terrain، and the fact that large-scale circulation patterns، as well as local، regional، and extra-regional circulations affect this region، has caused the climatic characteristics of the region to become very unique. The south part of the Caspian Sea receives a significant rainfall in autumn and winter، but in contrast، the least amounts in spring. The incidence of extreme rainfall and flooding in this season could impose damages to the region. Therefore، it is reasonable to identify mechanisms of development، strength، and laws of movement and extension of the synoptic and dynamic patterns to amid positive effects and avoid the harmful results or decrease them. Dynamical studies have a very special place in the study of climate of a region، so that by using the dynamic indices، we can analyze more accurate atmospheric phenomena. This paper attempts to apply a dynamical and synoptic approach to investigate extreme spring precipitation، zoning amounts of total rainfall of every pattern، and provide a model for dynamic and synoptic patterns in the study area. Study Area: The study area is includes the northern provinces of Iran، Gilan، Mazandaran and Golestan in the southern coast of the Caspian Sea and north of the Alborz mountain. This area is between latitudes 36 degree and 34 minutes to 38 degree and 28 minutes of north and longitude 48 degree and 50 minute to 54 degree and 2 minute of east (figure1). Also the rainiest stations and consequently perennial rivers and dense forest cover has been in this region of Iran

In this study، a statistical - synoptic method is used to investigate the dynamical patterns of the extreme spring precipitation in the southern coast of the Caspian Sea. In this regard، the daily rainfall data from 11 weather stations located on the southern shores of the Caspian Sea over a period of 50 years (1961-2010) were obtained from Iran Meteorological Organization. The selection criterion for extreme precipitation is the 24-hour rainfall in which 70% of stations would be equal or more than 20% of the long-term average of the seasonal rainfall. Using data from National Centers for Environmental Prediction / National Center for Atmospheric Research with a horizontal resolution of 2. 5°×2. 5°، the prevailing daily average atmospheric conditions were analyzed. The data include geopotential height، the zonal (u) and meridional (v) wind components، specific humidity and vertical velocity for 1000 hPa and 500 hPa levels. By using abovementioned data، the dynamical parameters of relative vorticity، vertical velocity، divergence and convergence of wind fields and vertical profiles of relative vorticity، divergence and convergence of wind fields separately for each model studied and produced by GrADS software. The maps were analyzed and finally dynamical patterns were identified.

The main objective of this study is to determine the extreme spring precipitation patterns associated with the dynamical quantities in the north coastal strip of Iran، so the weather map of severe-pervasive rainfall are extracted and dynamical analysis is done. The 500 hPa level maps show that the extreme spring rainfall in the southern coast of the Caspian Sea mainly follows four patterns. The main feature of the first pattern is the blocking system (Omega)، which is primarily located in the east of Europe. The system is created from the northward extension of high pressure of North Africa and southward development from the low level polar front in high latitude and also strengthening of a blocking system by the Mediterranean cyclone. In this pattern، Mediterranean cyclones are a major factor of spring rainfall in the southern coast of the Caspian Sea. Also، the European cyclones with amplification by low heights of the high latitude will cause a large amount of rainfall in this season in the north of the country. In addition، the extension of the Saudi high pressure to the East، and expansion of the subtropical high pressure outbreaks to above 80 degrees north latitude، makes a good condition to merge the European cyclones and Mediterranean cyclones in the study area، which eventually lead to create the heavy rainfall in the northern region of Iran. The third spring rainfall pattern is influenced by blocking systems in the Central Asia and Siberian regions. However، the expansion of the subtropical high pressure in the north-east and existence of the Saudi Arabian high pressure in the south of country، have a negative effect on the trough of low heights so that it prevents the system to create heavy and flash flood rainfall and it decreases the rainfall. In the fourth pattern، the blocking system is the dominant form of the spring precipitation in the southern coast of the Caspian Sea. This pattern is somewhat similar to the first pattern، which the different subtropical high pressure systems abnormally extend to the north in the spring. It is observed that even outbreaks reach to the 50°-60° N. In addition، low heights of the high latitude and Mediterranean cyclones also play a major role in the precipitation pattern. To provide a comprehensive view of the nature of atmospheric circulation in the southern coast of the Caspian Sea in spring، vertical profiles of divergence and convergence in patterns of along the 37 N were prepared. The results showed that the southern coast of the Caspian Sea and East Mediterranean during the active patterns of precipitation in the spring have a prevailing western streams (Eastward) at levels of 500 hPa to 150 hPa. Eastward flows through the orbital inclination have the maximum intensity in 300 hPa to 100 hPa levels and areas of divergence maxima and minima convergence and also the fields of horizontal divergence and convergence match at 1000 hPa.

The results showed that extreme spring precipitation in the southern coast of the Caspian Sea follows four major patterns. The main feature of the first pattern is the blocking- omega system that is located in Eastern Europe and Ural Mountains that lead precipitation induced systems to the southern shores of the Caspian Sea. In the second pattern، the Mediterranean cyclones are considered as a main factor of the spring rainfall in the study area. The third pattern of spring rainfall is formed when a blocking system exist over Siberia and Central Asia. Finally، in the fourth pattern، the blocking system is also the main cause of spring precipitation in the southern shores of the Caspian Sea. This pattern is somewhat similar to the first pattern، which is different from the subtropical high pressure systems abnormally extend to the north in spring. It is observed that even outbreaks of it reaches to the 50°-60° N. Investigation of the dynamical parameters showed that during the activities of the system، in all cases، the vertical velocity of the atmosphere is negative and the positive vorticity is high and the convergence zone is located on the shores of the Caspian Sea. All these factors imply that the dynamical weather condition in the region is appropriate for dynamically fast rising of particles to the middle and upper atmosphere، which eventually create heavier spring rainfall.

Wide Impact range of dust storms is one of the major characteristics that influence thousands of kilometers. The evaluation of relationship between wind speed and direction، visibility، air pressure and precipitation with frequency of dust storm occurrences in long-term، provides a complete knowledge of their content and provides useful information for solving this phenomena. The major sources of dust aerosols entering to west of Iran is Syrian-Sahara and Nofoud-Sahara in north of Arabian Peninsula (Zolfaghari، 2005). Study area: In this study we investigate dust storms، in Sar-Pol-Zohab (lat 45̊ 57́ 45̋، lon 34˚ 3́ 45̋)، using meteorological data. So، we intend to analyze speed and direction of winds during dust storms. The study area is a semi arid region، with mean precipitation of 421. 3 mm annually. Meteorological data was obtanied from Iranian Meteorological Organization during 1986 to 2009 which includes: Frequency of occurrence، storm types، speed and direction of wind، relative humidity، air pressure، and visibility. WRPLOT View software version 5. 3 was used to draw annual، seasonal and monthly windrose plot. Then the data were statistically analyzed using SPSS 17 software. Finally SURFER 8. 0 full version software was used to analyze the relationship between speed and direction of the wind and visibility. In this study we focus on widespread dust in suspension in the air that is not raised by wind or near station at the time period which includes time range between 14th of July 1986 to 2009، totally 152 storms. The frequency of dust storms has increased during recent years. Monthly investigation showed that the maximum days of dust storms occure in July by 4. 5 day per month and 108 days in the whole period. The minimal occurrences are in December. The most frequent dust storm days are seen in warm months (June، July and August) and the least frequent dust storm days are seen during cold months (November، December and January). The investigation of visibility، precipitation، relative humidity، pressure and speed and direction of the wind reveals an average decrease of 4313 m that in some cases it is decreased to 100 m. Relative humidity was 35. 4% and pressure of 1006. 55 hPa is reported. The average speed of wind was about 5. 1 knot and the direction was mostly west to south. Correlation investigation between climatological factors and visibility shows a weak relationship between the two، but there is a direct relation between speed of the wind and visibility. Investigation period is divided into two periods: (1) windrose at highest rate and (2) windrose at lowest rate which the following characteristic are seen in each period respectively. In first period western، northern and south western winds are seen which western wind (11 knot) plays a major role. In the second period، western winds are decreased and southern winds are increased، and the speed of wind in this period reach to more than 22 knots. General analysis of whole period shows that western، north western and south western winds play major role during storm events. Monthly windrose analysis reveals that winds directions were western during the months that dust storms had been increased. Also result showed an increase in the number of the storms that are not raised by wind or near station which tends toward west. Monthly trends verify the increase of storms in warm seasons due to a decrease in humidity. With respect to the results، we can calculate that the dust storms are originated outside of this region and Aeolian-sediments are not from this region. Also in this region dust storms occur at low speed of wind.

The rapid increase in population، economic and technological development along with changing consumption patterns lead to production of large amounts of waste in rural areas. This has caused a serious crisis in human societies. Currently، there is no integrated management of rural waste and rural waste has been converted to non-degradable waste with long-term survival. This waste remains in villages and rural areas for long time and gives villages an ugly face and it results in different types of air، water، and soil pollution. Thus، protecting the environment of rural areas is of significant importance for rural development requirements. In this paper we attempted to impose a variety of spatial analysis operations، along with the use of GIS technology and AHP model in order to locate the optimal boundaries - with the least adverse environmental impacts - in rural areas used for waste disposal. Study Area: Khaf، the border counties of Khorasan Razavi that is located between latitudes of 34°01''“N to 34°59''“N and longitudes of 59°28''“E to 60°55''“E is located on 250 km southeast of Mashhad in Iran''s eastern border، adjacent to Afghanistan in a relatively broad plains. In this paper، a descriptive - analytical method is applied based on the purpose of the study. In this paper، status quo analysis and data modeling procedures are used. To do this، first، we created database of GIS consisting of spatial data and descriptive data in forms of algorithm، spatial data (slope، land use، distance of faults، stream، roads and water sources، groundwater levels، etc.) of 10 Villages of Khaf city (with an approved pilot plan) from corresponding maps and by using ArcGIS software. Also، descriptive data were digitalized and stored to provide analysis capabilities. Then، a questionnaire was designed and completed by 30 people including three groups of university professors، consultant engineers of rural pilot projects preparation، and experts of Housing Foundation of Islamic Revolution. Ultimately، using weight of the layers in AHP model، and GIS database with overlapping operations of different maps in locating، landfill in rural areas were identified compared with current and proposed location of (approved by plane pilot) rural waste disposal. The main research question of the present study is that what factors influence the location of landfill in rural areas? And to what extent the current and proposed waste disposal site in the villages under study is in compliance with positioning of landfill in GIS environment? Selecting a landfill is the most important step in developing a satisfactory plan for waste disposal. While preparing the master plan، the sanitary landfill، if possible، should be determined and purchased. The most important factor in a successful operation of a landfill is its appropriate site selection. Many factors should be evaluated for the suitability of a landfill. Type of selected terrain has a direct impact on designing، exploitation operation، and required tools. 11 experimental parameters used in landfill location are: «Slope، distance from historical centers، distance from fault، distance from the watercourse، distance from the ways of communication، material of mother stone، lands use، distance from population centers، distance from the drinking water wells، level of underground waters، and the soil depth.» In the evaluation performed، soil depth with coefficient of 264. 0 has had the greatest impact on positioning of landfill and land use with coefficient of 014. 0، has had the lowest impact. In a comparative study between the existing landfill in rural locations with optimum positioning obtained by the software، it is identified that landfill in Chaman Abad-Vali Abad village is located in quite appropriate area and as for two villages، Syjavand and Chahzoul in appropriate area while landfills in other sample villages are located in fairly proper and improper areas. Research findings show that using this method and in case of multi-options and a large number of criteria the final option can be selected accurately. Logical and accurate weighting should be done for criteria and options to select the ultimate site and prioritization of landfills can be conducted accurately. The results can be used in regional planning to minimize urban and rural settlements damages. The results of this research can be planned with environmental and socio-economic perspectives and considerations and lead to a sustainable development. According to the studies and results obtained during the research process، the following suggestions are offered:  To identify suitable landfills in the rural areas، one of the best models is AHP model، which along with other models (ANP) and using ArcGIS software paly an important role for making decisions and guiding future development in rural areas;  Rural plans consultants'' coordination with local officials، particularly، rural Islamic councils and county rural municipality administrators is necessary to select and transfer landfill space because، finally، implementation of this project goes back to the local authorities. This place for waste disposal for a number of villages in a given geographical area is homogeneously identified.  Positioning landfills in rural areas is not a particular case for a particular village but a suitable location can be used for a collection of villages. Determining a suitable location for homogeneous rural areas and interval of garbage collecting that is economical.

In general، the risks can disrupt the system or parts of it and disturb its stability. The diversified of tourism dimensions and its nature caused that tourism to be a systematic feature. Tourism system is mainly open system so that، tourism system is man-made، possibility and complex. This system contains an internal structure and an external structure. Therefore، risks and events can affect the system structure and disturb it. According to previous studies، tourism system risk is composed of a number of types of risk، physical–the risk of physical harm to the consumer as a result of the functioning of the product; financial–the risk that the money invested in the product will be lost; performance–the risk identified with the possibility that the product will not operate as expected; social–the fear that the purchase will not conform to the standards of the reference group; psychological–the fear that the product will not be compatible with the self-image of the consumer; time–the possibility that the consumption of the product will be overly time consuming; and opportunity loss–the risk that by taking a course of one action، the consumer will miss out on doing something else he or she would prefer to do. Also، some researchers have pointed to the health، terrorism، crime and political instability risks. The main purpose of the study at hand is therefore to explore the risks that are relevant to system of tourism in Khoram Abad. So that in this paper، we use the membership grade of possibility and severity to establish the analysis of tourism risk. Study Area: Khoram Abad is located in Lorestan Province. Its area is equal to 4936 Km2. This county has great potential for tourism development. Tourism attraction in this study area involves historical، nature based and cultural resources. Such as، Falak ol Aflak، Kio leak، Nojian fall، Gahar، Kashkan Bridge، etc. The tourism system of this county is proposed to risk and vulnerability due to the lack of available attractions for tourists and tourist facilities disproportionately، dangerous environment for tourists، environmental pollution، planning and administrative problems and unfamiliarity of host communities with tourism field. Risk assessment of tourism system has done based on Iso 31000 risk management manual. The first stage includes risk identification. The risks are determined based on theoretical studies and Delphi method. The second step involves risk analysis. In this step Dematel model and Analytical network process are used. Dematel methods can identify causal interdependence between elements of the system through a diagram. ANP model has calculated the priority into a nonlinear process. The final step is evaluation and assessment of risk which we used Topsis model to classify the risks. The statistical population includes three groups. The first group is the experts and Professionals. The second group contains tourists in Khoram Abad and the third group is managers of tourism. Tourist’s sample size is equal to 195 persons and the sample size of managers is equal to 50 persons. According to the result of Dematel and ANP models، the performance risk has the most severity. Risk based on severity includes safety and security risk، financial and economic risk، political risk، social and cultural risks، law risk، technological risk and health-environmental risk respectively. The result of possibility of risks shows that Law risk and technological risk are the most probability. Then، these two factors are combined and then evaluated level risk. The results indicate that the performance risk show the highest level. Finally Topsis results show that the level of risk in this county is moderately high. The result in this study shows that، the most important tourism risk factor are performance and operational risks in Khoram abad county. Overall، social dimensions - cultural، political، legal، economic، security، and infrastructure management، technology and the environment will affected the future prospects of tourism. These dimensions are divided into two main groups. The first group includes external factors، which is related to environment and Exogenous variables that impact on the tourism system. The second group is related to internal elements and Endogenous properties affecting in this system. In this study we have attempted to examine all factors that are threatened sustainable tourism development process and disorders that may be hurt to tourism system. Also، in this study، management and assessment of risk process it reviewed in tourism destination. So، truly and realistically identification and examination of risks is essential in tourism management and planning activities. This risk contains management factors، administrative factors، marketing risk and human resources risk.