JOURNAL OF NATURAL ENVIRONMENT HAZARDS
Year:2018 | Volume:7 | Issue:17 |Papers Count:14

Characteristics of basins and their erosion and sedimentation are of great importance in the studies of water resources. Moreover, soil erosion is a problem that causes great damage to the economy of the country every year and reduces or kills soil fertility. Lack of information on soil erosion studies is the most important problem in these basins. Therefore in order to study the corrosion portraying the Sadal watershed erosion using and identify sensitive watersheds MPSIAC models and development effort to review and assess erosion and sedimentation in this area. The results showed that the sensitivity of the nine factors in the model MPSIAC both soil and slope erosion and deposition zone in resonance parameter are effective. The most critical factor in exacerbating erosion on a development model, so that the average increase in steep slope areas are areas of erosion and sediment yield increases. Review erosion and sediment production in both models suggests that the area with the highest erosion and sediment Q1 and its associated sub-basin D is minimal. The minimum difference between the estimated amount of erosion and sedimentation in the basin B (19. 23%) and most of the area between Q1 (28/48%) respectively. MPSIAC can estimate the erosion model development. Differences in erosion and sedimentation in sub D has the lowest amount is about 28% In general, estimates of erosion and sediment production in the Sadal watershed model MPSIAC middle class and low class is extensibility. Studies show that much of the West (H) to the East (exit) to move on erosion due to uncontrolled exploitation and overgrazing of pasture and mines as well as industrial and population growth will increase. On the other hand, the scope of the output (Q1) is added to the average value of the slope and the influence of soil type affect the amount of runoff and erosion and consequently increased.

Iran is one of the countries in the Middle East and North of Africa that face high risk in terms of wildfire occurrence in forested areas. We had used the record data SLP, 850 and 500hpa, temperature, precipitation, relativity humidity, speed and direction wind and forest fire day by IRIMO Golestan province. Data of SLP, 850 and 500hpaduring study period extracted from NCEP/NCAR data site. At first, the forest fire day’ s record by NRWM Golestan province. The addition, topography data obtain of DEM layers. The results show that: In the case of fire, wind speed increased, temperature 2 to 6cº will be increased but the relative humidity and precipitation are decrease trend. The analysis upper air data show that the fire occurred on the warm advection and increasing the thickness of the atmosphere in 1000-500 hPa level. Other results obtained from the difference between warm season and cold season is the wind flow pattern. In cold season, the flow of the south (the Oman Sea and the Persian Gulf) and Alborz Mountains creates a foehn wind (Germich) and warm season the Azores high-pressure tab control and a low pressure (thermal low) in the heat in the desert of Turkmenistan suitable for northern wind and fires are created. Therefore, these patterns are reason wildland fire in Golestan province.

Agriculture is the only activity which hurts the nature the least but becomes affected by natural circumstances, especially weather. Hailstone is among the most important dangers which make agricultural activities unstable through damaging agricultural products. Therefore, recognizing climates and studying climatological needs of agricultural plants, through fostering and utilizing human knowledge about atmospheric trends, leads to quantitative and qualitative improvement of products and subsequently stabilization of agriculture. Thus, the aim of the present research is the comprehensive study of temporal-spatial distribution and synoptic condition of these destructive phenomena For this purpose, the statistical data 23, 10 synoptic stations (2014-1992) in the growing season (April to September) with a choice of 4 cases of severe rainfalls and hail as well as data center NCEP / NCAR maps synoptic sea level 500, 850 and 1000 hPa cold wind, humidity, light, omega and frost formation in the application environment is drawn Grads. 9 to 15 (with peak rainfall at 12) Greenwich Mean Time GMT)) and the months of April, May, and June, respectively, had the highest frequency. The maximum frequency of occurrence in the region, in addition to local factors such as topography them (with altitude above sea level), the log-in system causing precipitation as west winds has an effective role. Located deep valleys caused by west winds with very cold air activities in the North, Mediterranean and Black Sea on the moisture, extreme temperature difference between the surface (due to the advection of warm, moist air at ground level) and high levels (with cold fronts) and ground-level air mass rally led by the highest frequency of hail in the spring (peak rainfall in April and May) is.

Climate change is not only caused the rise in temperature but also changes in the global precipitation cycle, which leads to variation in spatial and temporal precipitation patterns. In this study, climate change impacts were investigated on temperature, precipitation, and evapotranspiration of Neyshabour plane with the uncertainty of AOGCM models and emissions scenarios in the future period (2080-2099). First, the minimum and maximum temperature and precipitation for ten models of AOGCM under scenarios A2 and B1 in the future period and the baseline period of 1992-2011 were prepared and then downscaled by using of LARS_WG model. The reference evapotranspiration was calculated by FAO-Penman-Monteith method for all models and emission scenarios. The result showed that the value of evapotranspiration and temperature during the warm months were increased and the value of precipitation was decreased during the cold months. Also, monthly uncertainty was investigated for minimum and maximum temperature, precipitation, and evapotranspiration. The temperature and evapotranspiration in the warm months and precipitation in the cold months have less uncertainty than the other months. Also, the results of uncertainty analysis for models and emission scenarios are showed that NCARPCM and HADCM3 models in the estimation of minimum and maximum temperature, CGCM3T47as well as GFDLCM2 models in the estimation of precipitation have the best uncertainty results based on the two scenarios, respectively. The uncertainty analysis of AOGCM models determined that the best of uncertainty in the estimation of reference evapotranspiration for two scenarios is observed in the result of GISS-ER model. Also, the A2 scenario has the better function than the B1 scenario in the estimation of evapotranspiration parameter.

Frost is a climatic phenomenon in which water is at or below freezing point. A frost day refers to a day when the temperature goes down under zero Celsius degree throughout the night. Frost has important impacts on various aspects of human life, especially on agriculture and food productions. In the current study, the non-parametric (Mann-Kendall), parametric (Pearson correlation coefficient) and Innovative Trend Analysis (Sen) procedures were used to evaluate the effects of changing the trend of frost threshold in Northwest area of Iran. Based on Mann-Kendall and Pearson tests, there was a negative trend at Ardebil, Parsabad, Makoo, Maragheh and Mahabad stations, however, this effect was significant only at Ardebil station (p<0. 05, Mann-Kendall). When Innovative Trend Analysis (Sen) method was used for Mahabad station, a decreasing trend was found for all values, while this method had no trend in Maragheh station. Tabriz and Makoo stations showed negative trends only in a small band (5%) while other values at two bands had no trend. Except for small band (10%), Ardebil station showed a negative trend in other values. Urmia, Parsabad, and Khoy stations had a negative and positive trend in some cases, respectively. Evaluation of threshold changes of the climatic phenomenon can lead to making better decisions especially about agriculture, water resources management and climate change adaptation strategies in this region of the country.

The morphological studies and researches are very important for organizing the river and determining the river bed and zone. There are several hydraulic factors that make the scouring phenomenon intense at the location of hydraulic structures constructed on the beach of the river. The seawall erosion of river via water is regarded as the common and known phenomena of rivers of Khuzestan Province. So, execution of conservative practices and stabilization of side walls of the river is so essential. In the present research, the main aim is to determine the best method for stabilization of coastal on the basis of the study area by simulation and comparison of various conservation methods of coastal. For this purpose, a range of Zohreh River with the length of 60 Km was selected as the model area along with coastal protection structures. The organizing methods of the research encompass groin, riprap layer, construction of the concrete wall, vegetation, embankment and submerged plates. First, the river was modeled in Arc View software using topographic maps and the obtained results were imported into HEC-RAS software for applying hydraulic conditions. Then, various parameters of flow under conditions of organizing methods were compared with current state of the river. Finally, the groin-embankment option was selected as the best method in terms of hydraulic among alternatives, due to a %13. 5 reduction in shear stress relative to the existing conditions, implying erosion decrease of river coastal.

This study carried out for considering the intrinsic vulnerability of Oshnavieh plain aquifer using from DRASTIC and SINTACS models with respect to increasing groundwater resources contaminations and quality deterioration by agricultural activities, industrial and urban development. Although, cleaning up of groundwater contamination is very costly and long process and often occurs when contamination is detected that decontamination of the aquifer is almost impossible. One of the methods for preventing groundwater pollution, identify areas vulnerable aquifer. For both models, seven hydrological and hydrogeological parameters such as depth to water table, net recharge, aquifer media, soil media, the impact of the unsaturated zone, hydraulic conductivity and topography were used. After preparing the layers of each of the parameters in the GIS, the layers have been combined together and the final map was prepared for the plain vulnerability. For ensuring from results of the vulnerability models nitrate data collected from 25 agricultural wells in September 2015 were used. For models optimization and efficiency, the correlation between each of the parameters with the values of nitrate was considered and according to the correlation results and expertise the model parameters were changed and the weight of each final map was prepared. Corrected DRASTIC and SINTACS models showed 76. 3 and 67. 56 percent correlation with nitrate values respectively. Vulnerability index obtained for corrected DRASTIC was from 68 to 191 and for the SINTACS from 108 to 224. The results showed that both Corrected DRASTIC and SINTACS models are appropriate to determine the vulnerability of Oshnavieh plain. The corrected DRASTIC and SINTACS model determines the intrinsic vulnerability of the plain better than the corrected SINTACS model. according to DRASTIC and SINTACS vulnerability models have the highest potential vulnerability of Central Plains and the Southwest and Plains Margin the least amount of potential vulnerability.

The Study area in Asadabad plain is part of the Karkhe river watershed. Reduce in rainfall and increase in exploitation of groundwater resources led to a sharp drop in groundwater levels and subsidence’ s phenomenon in recent years has. The aim of this study is the hydrogeological evaluation, a better understanding of aquifer and optimal utilization of groundwater resources by using available data. In order to provide the mathematical model, geological, meteorological, hydrological and hydrogeological data were collected and then analyzed. Then according to the aquifer’ s conceptual model, the mathematical model was developed with PMWIN software. The model was implemented and calibrated for 2006-2007 with 12 stress periods. The sensitivity analysis showed that model has a more sensitive to hydraulic conductivity. The model was verified with observed data for next year (2007-2008). The results show that model is unable to simulate aquifer’ s natural conditions. The main reason was the uncertainty in input data and lack of piezometers in a large part of the aquifer's second layer. Study the effective factors on subsidence phenomenon (groundwater level fall, aquifer’ s type, aquifer’ s thickness and existence confined aquifer) showed that the central and southern parts of the plain have more vulnerable capabilities than the subsidence phenomenon.

Predicting of the river discharge is one of the most important issues in the planning and management of water resources in terms of energy generation, water allocation and use of water resources. In this study, the trend of climate parameters such as temperature and precipitation and so discharge as a hydrologic parameter were investigated based on the Mann-Kendall test and then was modeled and predicted the discharge of monthly streamflow Godarkhosh in the period 1992-2012, using linear time series SARIMA. To investigate the static model, tests autocorrelation (ADF) and partial autocorrelation (PACF) were used. The results of the Mann-Kendall test indicated the temperature parameter has an increasing trend and precipitation and discharge parameters showed reduction trend at all stations of the studied area at 99% confidence level. Also, the result of time series model indicated that the time series data of river flow were non-static data that with the differencing method, the non-static data transformed into static data. Then different models were fitted into static series to estimate the river flow and finally, model ARIMA (1, 0, 0) (0, 1, 1) was selected as an appropriate model to predict discharge and the river flow was predicted for 4 years from 2013 to 2016. The results showed that the discharge has increased at the end of the period, in which the model estimated river flow as well based on rainfall data from Meteorological Organization in the 2015-2016 year. Therefore, application of time-series models in water resources management can be useful.

In this study, Neural Fuzzy Inference System (ANFIS) was used in landslide zoning in the Songhur Chai River Basin. In order to assess the neural network, 124 occurred landslide data identified from aerial photographs, satellite imagery, and field observations and was presented to the system. In addition, for processing landslides in MATLAB software, 8-layers were prepared; slope layers, aspect, DEM, lithology, hydrographic network layer, NDVI, soil and landslide groups and landslide distribution were drawn from field studies, topographic and geologic maps and satellite images in Arc GIS software. These layers were normalized based on the largest value for each layer in the range between 1 and zero. During the modeling process, 80% of the data were selected for training and 20% for were tested and were processed in the neural fuzzy inference system. In several studies, the value is considered as acceptable. Then, the values in order to map the landslide in the structure of ANFIS were processed and analyzed. Finally, with respect to the output weights, landslide zonation maps were drawn in five categories: very high, high, medium, low and very few. The results indicated that the geological structure formed of gray man and red sandstone, volcanic ash and tuff and high humidity, makes Ganjgah Mountains and Islamabad a high potential area for landslide occurrence.

In recent years, there is much more attention to extreme climatic events. Also, it is proved that changes in intensity and frequency of these events have more destroyer effects on the human health, social and natural systems than changes in the mean climatic situation. The objective of this study was a recognition the effective extreme climatic indexes on winter wheat yield in Khorasan Razavi province. So, daily maximum, minimum temperature and rainfall data of 20 stations of this region were used in the 1982-2011 period. Also, the daily data of CORDEX project in the 2021-2050 with RCP2. 6 and RCP 8. 5 were analyzed. The yield was simulated with the calibrated and evaluated a model of AquaCrop. Mean yield in the past, future with RCP2. 6 and RCP 8. 5 were 3. 79, 4. 88 and 5. 24 tons per hectare, respectively. Increase in temperature and CO2 concentration was the reason of this increase in yield. Results of regression analysis showed that in all periods, effective extreme indexes were temperature-based. The indexes of a number of frost days and days with a minimum temperature lower than the minimum air temperature in the stem period’ s threshold were effective in all periods. The production risk was calculated based on probability and the impact of extreme climatic indexes. Results showed that the northern and central regions of the Khorasan Razavi province have the high to moderate and the southern parts have low risks. Also, it is concluded that the percent of low to very low risk was decreased and moderate to high risk was increased in the future. This means, however, the yield will increase, but the regions with low risk of extreme events will be decreased.

Desertification event by eliminating plant cover leads to the unfavorable effects such as erosion, land degradation, accelerated floods and also unfavorable environmental outputs. In the investigation of pedological criterion affecting on land degradation in alluvial fans Surrounding Halghe Dareh and Jaroo Mountains, Eshtehard, Karaj, first, maps of slope classes, land use, and geology were created, then a map of units was founded by overlaying and crossing these maps and grid layer created by extension of ET GeoWizards in ArcGIS 10. 3 software. In this research three indices of erodibility, salinity and permeability of soil were considered, finally, each of them was shown in the shape of the classified map. In this study, soil sampling was carried out to create maps of salinity, 159 samples, and permeability, 174 samples. Then, weights of criteria and consistency ratio were calculated by AHP method. In this research, FUZZY SAW method was used to prioritize the options, in the manner that after defining the triangular fuzzy numbers in four and seven level scales, the preferred index was calculated. The results show that the preferred index obtained from AHP-FUZZY SAW technique alters from 0. 254 to 0. 889 and 0. 236 to 0. 903 for four and seven level scales, respectively. According to the four levels of linguistic variables, 74/18% (4245/77 ha) and 25/82% (1477/67 ha) of the area were classified into two classes of low and very high desertification potential, respectively. The results also showed that in the seven levels of linguistic variables, 74/18% (4245/77 ha), 9/78% (559/53 ha), and 16/04% (918/14 ha) of the area were classified into three classes of low, high, and very high desertification potential, respectively.

One of the natural hazards that threaten our country's many world cities, including the earthquakes. The city Dena Given the existence of active faults, seismic areas, lacks of standards, poor physical development, and so this is no exception. The aim of this study Dena township spatial zoning of seismic hazard identification and urban settlements located in areas with a high-risk earthquake zone. The results show that 11/79 percent of 124/33 square kilometers township Dena has a high seismic risk of the entire city. 27/40 percent to 288/83 square kilometers is a risk of high seismicity. The results showed those 411/23 square kilometers, equivalent to 32 percent of the city Dena have a low seismic risk. According to the results, Pataveh in terms of the risk of earthquakes in the seismic risk is relatively low, medium, and hard disks in terms of seismic risk are relatively moderate and high and areas around the city are a very high seismic risk. Also, 17/12 percent From villages Dena township are In high-risk zones, 97/33 percent, In the medium risk zone, 25/35 percent In areas with low risk, As well as 29 villages, Equivalent to 58/18% of rural settlements and villages In the earthquake zone, with no risk. The highest area of hard disks in the high and very high-risk zone with an area of 215 square kilometers and the largest area of high seismic risk is in the range high which is equivalent to 278 square kilometers. Strategic review of the role of the ruler showed strength with weight matrix 204/0 in the first quarter and STweight strategy is 0/203.

There are many different methods for identifying meander changes and river landforms and prediction their movements. In this study, 55 km of Maroon river route changes in Behbahan district is studied in 16years time interval by using Landsat 7 ETM+ and Landsat 8 OLI satellite images for 1999 and 2015 respectively. In this study linear directional mean method is applied. This method represents general direction of vectors, that line and vectors are river routines in this study. River route is digitized and divided into four parts according to the geology of the study area, and then the linear directional mean of each part was calculated. All of four parts showed changes in length and direction. Results show that river length was 54897 min 1999 and changed to 55532 min 2015 and the movement of the mean center point of the river in the study area is about 180 m. Main changes in length are in 4th part about 88 m. A length change for the whole river in the study area is 635 m, which most of it occurred in 4th part. Land use of riverside in parts 1 and 2 have no changes, but the bare soil in parts 3 and 4 changed to rangelands and bushes in the study time interval.