انجمن ایرانی ژئومورفولوژیپژوهشهای ژئومورفولوژی کمّی225194245320181118Evaluation of Effective processes on the creation and development of Sand ramps (case study: Tang-e-Chenar basin)ارزیابی فرایندهای مؤثر بر شکل گیری و تحول کوهریگ ها (موردمطالعه:کوهریگ های تنگ چنار)11978050FAمحمدشریفی پیچون0000-0002-9456-5285فاطمهدهقانJournal Article20181118Introduction
Sand ramps are a kind of sedimentary accumulation found at the foot of the slopes of some desert and semi-desert region in the world. Sand banked up against mountain fronts or other topographical obstacle, forming a ramp (Bertram, 2003). For this reason they called sand ramps. The land form among the people of central of Iran is called Kuh-e-Rig, means a mountain of sands. Until the early 90s, sand ramps they was considered as sand dune. But more exactly studying showed despite more materials of sand ramps are sands, but there are huge differences between sand ramps and sand dune in terms of form, materials, and processes. Despite researches in the past, Sand ramps not form just only by Aeolian processes, but another geomorphological processes such as fluvial and colluvium processes. In fact, sands mound up against mountain slopes. Thus they may be seen as a falling or climbing deposits. Therefore, they are actually very complex landform and different of another sand dunes. Sand ramps contain a “variety of sediments formed in different environment including Aeolian, fluvial and talus deposits” (Bertram, 2003). The aim of this research is studying of sand ramps of Tange-Chenar Catchment located in the south of Mehriz city in the Yazd province. The study region is located in the west slopes of Shirkuh mountain with more than 4000 meters high between 31° 18´ to 31° 26´ of northern latitudes and 54° 18´ to 54°29´ of eastern longitudes.
Material and methodology
This research has been performed on basis of field studies and direct observation of sand ramps. But, we studied topographical and geological maps, DEM, satellite images as well as aerial photographs, at first. Therefore, the resulted information of the maps controlled with GPS System in the field. For studying sand ramps in the Tange-Chenar catchment, we visited the area in tow time periods involving 13/11/2015 and 30/9/2014. When visiting the area, we picked up some sample of sediments. Then, we took them to the laboratory of geomorphology, and put about 450 grams inter shaker set for any case for about15 minutes. The diameter of used meshes were 2000, 1000, 550, 355, 250, 125, and 63 mm in orderly. Then, using Gradistat software we calculated statistics parameters includes Mz, Md, SDI, SKI, and Ku. In addition, because of some sample were similar in terms of statistical parameters, we put them inside five statistical community. Finally, using SPSS software, One-Way ANOVA method and Tukey test, we did statistical comparisons and significance level between variables, to compare the relationship between these variable together and understand effective processes on the formation and evolution of the sand ramps.
Findings
As mentioned, for analyzing picked samples we have used of granulometry method and determined statistical parameters of sediments. Initial analysis show that some of sample are similar from point of statistical view. Thus, we placed them in five groups. Finding showed that the sample and the communities are different; Even though some of them have located in adjacent. The first community of sand deposited above the height of 2200 meters and coming down on steep slopes. Field studies showed that these deposits have descending under the influence of gravity. Thus, winds had no role in creating them. The sample of 7 and 8 are part of these community. The average diameter of sands are less than 600 microns in the sample 7, but it is about 1000 microns in a sample 8. The second community was picked from a river valley cut with 20 meters thickness. Four samples of it were taken from 2230, 2235, 2245 and 2250 meters heights. From sedimentology point of view, sands includes very coarse sand and gravels. Upper sediment were coarse size. Their histogram are bimodal and multi modal. The sediments have not sorted very well. The most of them are platykurtic and very fine skewed. The third community of sediments has located in the middle part of catchments next to a big river and big alluvial fans. Therefore, the volume of the sediment in this segment is very much that has brought by waters and transfer by winds on slow slopes and in some cases on the slopes. The samples of the community moderately well sorted but are fine skewed. The fourth community of sediments has placed in the downstream of the catchment where the slope is low. The sediment is affected by wind processes. The granulometric analysis also confirmed it. The samples of 6, 11, 12, 13 and 15 are in this community. The samples are very fine skewed, moderately sorted and very leptokurtic. The mean diameter of the sands is high, because mass movement processes have brought down gravel, pebble and boulder and deposited inside the sands. Finally, the fifth community includes just one sample. Because the sediments of the segment were seemed similar and uniform. The sample was taken from above 2400 meters height. The sediments of the sample has placed as debris cone on the slopes. The domain process to create them is physical weathering. Then come down influence by gravity.
Results
Results show that, contrary to initial thinking, winds have not been major role in the formation and development of sand ramps. Even though, the sediment characteristics and statistical parameters of this type of sediments is similar to sand dune that is created by wind process. Most of these sediments has located on steep slopes; they are scattered in different geographical directions; there are gravels and boulders between sediment layers that implicate hillslope processes. In addition, the sediments diameter, sorting, skewness and kurtosis are different with the sediment of sand dunes. کوهریگها گونهای از تهنشستهای رسوبی ماسهای هستند که در دامنه برخی تپهها و کوههای مناطق خشک و نیمهخشک تشکیل میشوند. در محدوده تنگ چنار در پای دامنه و بر روی دامنه کوهها تجمعات ماسهای با مورفولوژیهای متفاوت دیده میشود که اغلب آنها در شرایط کنونی ثابت بوده و احتمالاً مربوط به شرایط اقلیمی گذشتهاند. هدف این پژوهش بررسی این عارضهها بهمنظور شناخت شرایط و محیط شکلگیری و فرایندهای مؤثر در تشکیل آنها میباشد. برای انجام این کار به دانه سنجی و تحلیل رسوب کوهریگها در بخشهای مختلف منطقه پرداخته شد. بدین ترتیب، در مرحله اول 16 نمونه رسوبی از منطقه موردمطالعه برداشت و پس از دانه سنجی، تحلیل و پارامترهای آماری رسوبات بررسی شدند. به دلیل شباهت در مناطق نمونهبرداری و همچنین نتایج تحلیل پارامترهای رسوبی، نمونهها به پنج جامعه آماری با ویژگیهای تقریباً مشابه تقسیم و مورد تحلیل قرار گرفتند. همچنین، از تحلیل واریانس یکراهه و آزمون توکی جهت بررسی معنیدار بودن اختلاف بین متغیرهای مختلف در سطح 95 درصد برای بررسی فرایندهای مؤثر در جابجایی و نهشتهگذاری آنها استفاده گردید. مشاهده اندازه دانهها و سرت شدگی ظاهری آنها در نگاه اول حاکی از دخالت فرایند بادی در جابجایی و رسوبگذاری آنها به شکل تپههای ماسهای بیابانی است. اما، بررسی و آزمایش ویژگیهای رسوبی مانند شکل، اندازه ذرات و پارامترهای مختلف آماری و همچنین نمودار هیستوگرام کوهریگها در بخشهای مختلف منطقه حاکی از تفاوت رسوبات به شکل چشمگیر ازنظر نوع فرایند، مسافت انتقال و چگونگی نهشتهگذاری در منطقه موردمطالعه است. نتایج نشان داد که فرایندهای دامنهای، کوهریختی، فلوویالی، بادی، بادی-آبی در قلمرو مورفوژنتیک و مورفوکلیماتیک جنب یخچالی با رخنمون سنگهای دانهای مانند گرانیتها در شکلگیری و توسعه این کوهریگ ها نقش اصلی را بر عهده داشتهاند. https://www.geomorphologyjournal.ir/article_78050_7ac68a046264d9ccf8706f9d026b05cb.pdfانجمن ایرانی ژئومورفولوژیپژوهشهای ژئومورفولوژی کمّی225194245320181118Zoning landform evolutions potential affects the drainage network
Case study: river basin Gheshlaghپهنه بندی پتانسیل تحول لند فرمی تحت تأثیر شبکه زهکشی مطالعه موردی: حوضه آبریز رودخانه قشلاق203778051FAمجتبییمانی0000-0002-2042-7365فاطمهیوسفیانورمرادیموسیعباسیمحسنبرزکارJournal Article20181118Introduction
Flow of water is one of the major transformative landforms of small scale (such as a river beach) to large (planet Earth) .So in each basin management we need a comprehensive view about basins and identify the major problems to solve them with a planning application. The problems of the region to else show different level but transformation landforms affected drainage network is the most important. Gheshlagh basin is located in the central part of Kurdistan Province and and Like this Provincehas an abundance of water power. Basin located in Esfandaghe- Marivan zone that is the most tectonic active zone in iran. Geological Survey, climatology, soil, land coverage, physiography and hydrology, and particularly field studies defining the role of streams and rivers of the area in the form of the act of creation well water hazards on humans and his work also highlights.so the main objective of this research is Zoning landform evolutions potential affects the drainage network.
Methodology
The research is done in this step: the collection of data, field studies, production and conformity layers with the current situation, and an analysis of each layer and the hydromorphology parameters to find effective and integrated layers of information to identify sites that are potential development landform affected by drainage network. The method of collecting data including statistical methods, aerial photographs, fields visit references are documents and etc. Then according to geological properties geology, geomorphology, hydrology, climate, human factors and environmental impact and the use of comparative studies, five criteria and 13 develop objective sub was to investigate through fieldwork and resource documents are controlled. Finally, using AHP to analyze the quantitative criteria, sub criteria and combining the layers in ARC GIS software and mapping Venture to Zoning landform evolutions potential affects the drainage network
Results and discussion
Gheshlagh Basin located in Esfandaghe- Marivan zone that is the most tectonic active zone in iran. According to studies area is not uniform and has a variety of geological formations and a general look including limestone,andesite, basalt, shale and phyllite and etc.number of basin east faults, outed the Zagros general trend. Soils of the study area in two categories: Entisols and Inceptisols. The basin slopes facing north wetter and denser vegetation and thus more resistant to erosion, while south-facing slopes are relatively bare and erosion is more intense. Aarea,shape, slope, aspect, elevation, land cover, etc. all play a vital role in the behavior of the hydrological basin. Winter river basin area by using planimeter measured on 1:50000 map as well as the application environment GIS9.3 measure that is equal to 1834 square kilometers.Major drainage basins along the main channel from the Gheshlagh basin calculated the software ARC GIS9.3that is 94.19kilometers. To evaluate the effect of land slope on hydmorphology issues also influenced the evolution landform affects drainage slope map through the use of (GIS) has been prepared. Acording to Slope map of the study area on western highlands and the eastern highlands have the maximum slope and central and southern of study area have the lowest slope. ). inThe basin slopes facing north wetter and denser vegetation and thus more resistant to erosion, while south-facing slopes are relatively bare and erosion is more intense. Study area the drainage pattern branch tree that can perform general discharge. this pattern as a result of numerous factors, such as lithology and tectonic.by carefully on the studied the surface water network map we easily can expand the branch tree pattern in West and North West study area Most of the lithology observed that corresponded with silt and phyllite. So lithology and tectonic canconsidered the most important factors in creating the creating this pattern.
Conclusion
The main results indicated that the central parts of the basin to outlet have more potential for landform evolutions compared with other parts. results Was calculated in five categories very high, high, medium, low and very low and found that about 28 percent of the basin have high and very high potential for the development of land forms is affected by drainage. Most parts of northern and northwestern parts of the basin and the East Basin have the low or very low potential for landform evolutions namely about45percent.Other parts of the basin have the medium potential for landform evolution namely about 27 percent. Anywhere in the basin lithology is more resistant landform evolution is lower that this point is the more important point in this study.حوضه رودخانه قشلاق در غرب کشور، در قسمت مرکزی استان کردستان، در یک منطقه کوهستانی دارای شیب زیاد، با اقلیم مدیترانهای معتدل و گرم قرارگرفته است. هدف اصلی این پژوهش پهنهبندی پتانسیل تحولات لندفرمی تحت تأثیر شبکه زهکشی در این حوضه است. بدین منظور جمعآوری دادهها، مطالعات میدانی، تولید لایههای اطلاعاتی و انطباق آنها با وضعیت موجود، تجزیهوتحلیل هر یک از لایهها و پارامترهای هیدرومورفولوژی جهت یافتن عوامل مؤثر و تلفیق لایههای اطلاعاتی جهت تعیین پتانسیل تحول لندفرمی مکانهایی که تحت تأثیر شبکه زهکشی قرار دارند انجامگرفته است. همچنین با توجه به ویژگیهای زمینشناسی، ژئومورفولوژی، هیدرولوژی، اقلیمی، عوامل انسانی و زیستمحیطی منطقه، مطالعات تطبیقی و نظر کارشناسان امر 5 معیار و 13 زیرمعیار جهت تدوین هدف طراحی گردید و از طریق کارهای میدانی و منابع اسنادی نیز کنترلشده است. قدم بعدی تهیه لایههای اطلاعاتی موردنیاز برای پهنهبندی با نرمافزار Arc GIS9.3بود تا زمینه برای تحلیلهای لازم فراهم گردد. درنهایت با استفاده از فرآیند تحلیل سلسله مراتبی(AHP < /span>) به تجزیهوتحلیل کمّی معیارها، زیرمعیارها و تلفیق لایهها در نرمافزارARC GIS نسبت به ارائه مدل و پهنهبندی منطقه مطالعاتی مبادرت گردید. نتایج در پنج طبقه خیلیزیاد، زیاد، متوسط، کم و خیلی کم محاسبه شد و نشان داد که حدود 8/27 درصد از حوضه دارای پتانسیل زیاد و خیلی زیاد جهت تحول لندفرمها تحت تأثیر شبکه زهکشی میباشد. بیشتر قسمتهای شمالی حوضه و بخشهایی از شرق حوضه دارای پتانسیل کم و خیلیکم میباشند که 26/45 درصد از کل حوضه را در برگرفتهاند. سایر قسمتهای حوضه نیز بهصورت پراکنده دارای پتانسیل متوسط بوده که 94/26 درصد از مساحت حوضه را شامل میشود.https://www.geomorphologyjournal.ir/article_78051_07833479e72da91592ac31df369c30de.pdfانجمن ایرانی ژئومورفولوژیپژوهشهای ژئومورفولوژی کمّی225194245320181118Assessment the Effect of Drought on Karst Spring Discharge and forecast for future in Kermanshah Townshipپایش و پیشبینی اثر خشکسالیها بر دبی چشمههای کارستی شهرستان کرمانشاه385178052FAامان الهفتح نیاعلیاحمدآبادیسعیدرجائیجعفرمعصومپور سماکوشJournal Article20181118Introduction
Karst aquifers act as large natural reservoirs of rainfall, and spring discharges reflect periods of poor or abundant rainfall, as well as long term climate change. The annual discharge of karst springs depends on climate, geology and karst. The karst springs Discharge in a 42-year period in China shows that the discharge of Shentou Springs responds remarkably to precipitation change (Ma & et al.; 2004, 274). The determinations of large karst systems discharge have been analysis by the investigation of precipitation and supplement reduction periods. Data show that hydrologic year depended to last year precipitation. In Mediterranean climate and regional condition the annual peak hydrograph occurs during spring season. Also, Insufficient recharge due to poor annual rainfall affected the peak discharge in hydrograph; this hydrograph reveal drought which effected by reduction in discharge during the following year as well (Fiorillo; 2009, 290).
Study area
Study area consist of Kermanshah, Ravansar and Eslamabad_Gharb Township in west of Iran. SarabBiabr and SarabVarmenjeh spring located in North and SarabNilofar spring in south of Kermanshah plain. Weather station of Kermanshah located in longitude 47°, 9¢ E. and latitude 34°, 21¢ N. Weather station of Ravansar located in longitude 46°, 39¢ E. and latitude 34°, 43¢ N. Weather station of Eslamabad_Gharb located in longitude 46°, 28¢ E. and latitude 34°, 7¢ N.
Materials and methods
In order to study the long-time series of hydrological, Karst spring discharge and precipitation, we used from Standard Precipitation Index (SPI) and nonparametric Man_Kendall test. Also, the relationship between precipitation-discharge and lag time in short and long-term analyzed by Pearson correlation. In this study, we used monthly and annual data from discharge stations of SarabBiabr, SarabVarmanjeh, and SarabNilofar spring, and precipitation data of Kermanshah, Ravansar, and Eslamabad_Gharb Weather Stations for the period 1989-2010.
In the Man _ Kendall test, out of 95 significant level, indicated significant changes in the time series and determine real data behavior during the time series the ascent or descent of the series.
Also, was used from Markov Chain Model for the possibility of repeated periods of dry or wet and its effect on Dubai karst springs.
Result and discussion
Maximum amount of discharge are in SarabNilofar and SarabVarmanjeh spring. Since the beginning of the study period to 2010, Karst spring discharge decreases, the greatest loss is occurring in SarabNilofar spring. In this spring amount discharge from 1241 liter/sec has decreased to less than 100 liter/sec for year 2010. Karst aquifer is the main water source which influenced by fluctuations in the short and long term precipitation.
Conclusion
The present study was investigated on the effects of drought on rate of discharge and relation between discharges with precipitation. Also, effect of precipitation lag time on fluctuations discharge was studied. The result shown the most correlation was between discharge of SarabVarmanjeh spring (about of 0.639) and SarabBiabr spring (about of 0.642) with precipitation meteorology station of the Eslamabad_Gharb. So, SarabNilofar spring discharge (about of 0.484) had most correlation with Kermanshah precipitation meteorology station. In this paper, the authors obtained the lag time for the discharge values response to the precipitation factor, six months for long time and two months for short time. The reason of the difference between the two times is precipitation factors (such as monthly distribution, intensity and state of solid or liquid).
The reason of this difference is precipitation characteristics such as solid state, distribution, and intensity. The results of the Man – Kendall test showed that were increase in precipitation (1989-98) and then decreased (1999-2010). Also, SarabBiabr spring discharge shows the same trend. The most decreases fluctuations was in SarabBiabr spring discharge and the most decreases fluctuations in precipitation was during 2003. The SarabVarmanjeh spring discharge decreases from 1996 year. Precipitations on Kermanshah station had decreases during 1999–2010 years and observe this condition during 1999-2010 in SarabNilofar spring discharge and from 2009 year have changed. The results of the Markov test showed that Probability occurrence condition dry to dry in stations more than others conditions, this is in Eslamabad_Gharb 0.892, in Ravansar 0.89 and in Kermanshah 0.886. It should be noted that this represents the future trend of decreasing rainfall and consequently reduced rate of Karst spring discharge. Computation annual SPI showed which in droughts SPI precipitation is a very similar trend with spring discharge. Overall, the results of Markov Chain Model indicated an increased risk of drought in weather stations that will affect the future on Karst spring discharge declining in study area. Prediction of drought periods and that effect on Karst spring discharge could help us to planning for best use of Karst aquifer sources.آبخوان کارست در مناطق آهکی اهمیت زیادی در تأمین آب مصرفی دارند، این آبخوانها تحت تأثیر دورههای افزایش و کاهش بارش و همچنین تغییرات اقلیمی قرار دارند. بهمنظور مدیریت پایدار منابع آب، شناسایی تغییرات دبی چشمههای کارستی این آبخوانها ضروری میباشد. در تحقیق حاضر تحلیل سریهای زمانی هیدرولوژیکی، بین دبی چشمههای کارستی شهرستان کرمانشاه و بارش با استفاده از شاخص بارش استانداردشده، آزمون من- کندال و زنجیره مارکوف برای پایش و پیشبینی خشکسالی و اثر آن بر دبی چشمههای انجام گرفت. همچنین ارتباط بارش- دبی و تأخیر زمانی بهصورت کوتاه و بلندمدت با همبستگی پیرسون بررسی شد. دادههای تحقیق شامل دبی سرابهای بیابر، ورمنجه و نیلوفر و بارش ایستگاههای هواشناسی کرمانشاه، روانسر و اسلامآباد غرب برای دوره زمانی 88-1368 بهصورت ماهانه و سالانه بود. نتایج تحقیق نشان داد بین دبی سراب ورمنجه (639/0) و بیابر (642/0) با بارش ایستگاه هواشناسی اسلامآباد غرب و سراب نیلوفر با ایستگاه هواشناسی کرمانشاه (484/0) بیشترین همبستگی وجود دارد. به دلیل حالات مختلف بارش مانند جامد یا مایع، توزیع و شدت آن، اثر بارش بر افزایش دبی با تأخیر حداقل 2 ماه و حداکثر 6 ماه مشاهده شد. نتایج آزمون من- کندال بیانگر افزایش مقدار بارش (76-1368) و سپس کاهش (88-1377) میباشد که دبی سراب بیابر همین روند را نشان میدهد، و دبی سراب نیلوفر از سال 1387 دچار تغییر کاهشی شده است. نتایج آزمون زنجیره مارکوف نشان داد که در هر سه ایستگاه احتمال رخداد دوره خشک بیشتر از دوره بارانی است، در ایستگاه اسلامآباد غرب 892/0، در ایستگاه روانسر 89/0 و در ایستگاه کرمانشاه 886/0 میباشد. مطالعه نشان داد که احتمال افزایش دورههای خشک در آینده بیشتر و بهتبع آن دبی سرابهای موردمطالعه کاهش خواهد یافت. مطالعه شاخص SPI سالانه روند کاهش دبی با خشکسالی را نسبت به دورههای تر بهتر نشان میدهد.https://www.geomorphologyjournal.ir/article_78052_188a246b0043ad27c8873ef5be937638.pdfانجمن ایرانی ژئومورفولوژیپژوهشهای ژئومورفولوژی کمّی225194245320181118Effects of physicochemical properties of marls on their erodibility using rainfall simulator in Nowbaran, Savehتأثیر خواص فیزیکوشیمیایی مارنها بر میزان فرسایشپذیری آنها با استفاده از دستگاه شبیهساز باران در منطقه نوبران، ساوه526678053FAخلیلرضائیJournal Article20181118Introduction: According to the physicochemical characteristics and high rate of erodibility, Marl is one of the most important sedimentary units are in Iran. These properties caused large environmental and civil damages and so, the study of erosion and erodibility of the marl units is essential. One of the most important points about marls is grain size nature and elements in them and their effects on amount of erosion. The physical and chemical proprieties of soil are very important in the development of badlands. This study deals with the physicochemical characteristics of the marl units and their effect on various forms of erosion in Nowbaran Saveh region. Badlands are a typical landform of greatly dissected fine-grained materials in arid or semi-arid environments like Nowbaran, although they are also found in different climatic conditions. Badlands typically have steep, unvegetated slopes, high drainage densities, high erosion rates and a tendency to form a regolith profile with dried cracks, making the surface puffy. Climate and geology are several factors determining the tendency to badland formation. Runoff, rain splash, marl and loose formations together with massive wasting processes such as creep, sliding and flow, become the dominant factors determining landform genesis, resulting in the formation of badlands in Clayey-silt slopes.
Methodology: in this research, in addition to sampling the soil and sediments, rain simulated (using rain simulators) in three marl units in area with different forms of erosion and runoff and produced sediment amounts in each point were measured in laboratory. Also, parameters such as electrical conductivity, content of sodium, potassium, calcium, magnesium, gypsum, sedimentary particles agglomerate and SAR percent (SAR) was measured. In analyzing the data, analysis of variance and comparison of means method were used in SPSS software.
Result and Discussion: Mineralogical, geochemical and grain-size composition of soil and pore-water chemistry parameters was characterized on both eroded (south-facing) and non-eroded (north-facing). Only a few grain-size parameters and clay mineralogy discriminate eroded from non-eroded slope substrates. Erosion occurs where the fine fraction is abundant. This may be due to reduced permeability in the eroded soil, whereas the non-eroded one is more stable with respect to weathering, as it is more permeable. The abundance of clay minerals is affected by pedogenetic processes in the non-eroded slope, which increases in mixed layers and indirectly reduces the amounts of other minerals, making clay mineralogy a discriminating parameter in the two different types. Chemical data enable discrimination between eroded and non-eroded slopes. pH, SAR (sodium adsorption ratio), TDS (total dissolved salts) and PS (percentage of sodium) are distinctive parameters for both eroded and non-eroded slopes. TDS increases in depth in the non-eroded slope, whereas the maximum TDS is just below the crust in the eroded one. On average, eroded substrates are higher in pH, SAR and PS than non-eroded ones. The ESP (exchangeable sodium percentage) of the eroded slope has a higher value than the non-eroded one. So, clay minerals include sodium result high rate of soil erosion with gully landforms in this study area. Crusts are less dispersive than eroded substrates, and non-eroded substrates behave as crusts. This suggests that the portion of the slope most severely exposed to weathering tends to stabilize, due to strong decreases in SAR, PS and ESP. Several diagrams reported in the literature show similarly anomalous crust samples on eroded slopes, compared with other samples coming from greater depths on eroded slopes. In the present case study, the exchangeable form of Na characterizes crusts more than the soluble form. The meaning of maximum SAR and TDS (and covariant parameters) is interpreted as the effect of decreased permeability, as suggested by a local increase in the fine-grained fraction, which coincides with maximum TDS. Variations in SAR values are of primary importance for soil erosion, because many authors have used solution chemistry (i.e., SAR, PS, TDS, EC) as a descriptor of dispersivity.
Conclusion:
Based on results of analysis of variance in various forms of erosion are significantly different in the sodium ion, sodium absorption ratio and the percentage of clay. The average amount of sodium ion and sodium absorption ratio in marl samples of region, increase from sheet to gully erosion forms while average clay percentage decreases in this trend. Finally, three variables of sodium ions, sodium absorption ratio and clay percentage of marl samples can be significant factors in erosion and related forms in this region. This study describes the erosional mechanism, which involves morphological and geographic exposure and climatic elements, as well as grain size, mineralogy, chemistry and exchangeable processes of soils.مارنها یکی از مهمترین واحدهای رسوبی در ایران میباشند که به لحاظ ویژگیهای فیزیکی- شیمیایی از رسوبزدایی و فرسایشپذیری زیادی برخوردار هستند. ماهیت دانهبندی و عناصر موجود در آنها و تأثیر این دو موضوع در میزان فرسایش مارن ها بسیار مهم میباشد. در پژوهش حاضر به بررسی ویژگیهای فیزیکی- شیمیایی واحدهای مارنی و تأثیر آن بر اشکال مختلف فرسایشی در منطقه نوبران ساوه پرداختهشده است. بدین منظور علاوه بر نمونهبرداری از رسوبات، آزمایش شبیهسازی باران (به کمک دستگاه شبیهساز باران) در سه واحد مارنی منطقه بر اساس اشکال مختلف فرسایشی انجام شد و میزان رواناب و رسوب تولیدشده در هر نقطه در آزمایشگاه تفکیک و اندازهگیری شد. همچنین در آزمایشگاه پارامترهای هدایت الکتریکی، میزان عناصر سدیم، پتاسیم، کلسیم، منیزیم، گچ، درصد ذرات رسوبی و سدیم قابلجذب (SAR) نمونهها اندازهگیری گردید. در تجزیهوتحلیل دادهها از روش تجزیه واریانس و مقایسه میانگینها در نرمافزار آماری SPSS استفادهشده است. همچنین مقایسهای اجمالی بین دامنههای روبه شمال و جنوب که ازنظر فرسایش متفاوت میباشند، نیز انجام شد. بر اساس نتایج تجزیه واریانس اشکال مختلف فرسایشی در میزان یون سدیم، نسبت جذب سدیم و میزان درصد رس، دارای اختلاف معنیدار میباشند. میزان میانگین یون سدیم و نسبت جذب سدیم از فرسایش سطحی به فرسایش خندقی در مارنهای منطقه افزایشیافته و میزان میانگین درصد رس از فرسایش سطحی به فرسایش خندقی کاهش مییابد. همچنین سه متغیر یون سدیم، نسبت جذب سدیم و درصد رس نمونهها را میتوان عواملی تأثیرگذار در فرسایش مارنهای منطقه و ایجاد اشکال مختلف فرسایشی دانست. بنابراین بین نوع لندفرم و خواص فیزیکی و شیمیایی مواد سازنده و نحوه و میزان فرسایشپذیری آن ارتباط وجود دارد.https://www.geomorphologyjournal.ir/article_78053_19bd88a54f46ee0bacd494272fb5624f.pdfانجمن ایرانی ژئومورفولوژیپژوهشهای ژئومورفولوژی کمّی225194245320181118Assessment of Analysis Network Process and Logistic Regression in the Investigation of Landslide Potential in the Axis Range and Reservoir Dam
(Case Study: Ghalea Chai Dam)ارزیابی روشهای تحلیل شبکه ( ANP ) و رگرسیون لجستیک در بررسی پتانسیل وقوع زمینلغزش در محدوده محور و مخزن سد، مطالعه موردی: سد قلعه چای678078054FAشهرامروستائیلیلاخدائیJournal Article20181118Introduction
Management of natural disasters needful local information set able for perils and decrease of process them. At this contex the indication of the potential landslides in the area which due to geographical condition and the construction of human is prone to landslides is necessary.Ghalae chai dam is one of these areas.Therefor, the purporse that is followed in this study is that, the Motions and instabilities hillside and affective factors in it be known to deleterious effect of that be prevented in the field of the natural resources and in the other parts of construction of development and economic and areas with high potential risk is identification and be zonied. Therefore the main purpose of this research, is to assessment of Analytic Network Process and Logistic Regression methodi n determine the landslide prone areas in the range Axis and Reservoir of Ghalea Chai Ajabshir.
Methodology
To evaluate the potential of landslides in the dam area in this study to evaluate the efficiency of Analytic network process and logistic regression methods were investigated. ANP model building requires the definition of elements and their assignment to clusters, and a definition of their relationships (i.e., the connections between them indicating the flow of influence between the elements). Like AHP, ANP is founded on ratioscale measurement and pairwise comparisons of elements to derive priorities of selected alternatives. In addition, relations among criteria and sub-criteria are included in evaluations, allowing dependencies both within a cluster (inner dependence) and between clusters (outer dependence) (Saaty, 2001). Pairwise comparison is now done, both for weighting the clusters (i.e., criteria) and for estimating the direction and importance of influences between elements, numerically pictured as ratio scales in a so-called supermatrix. Network analytic was used to examines the potential of landslides for the first time in Iran and for runing it the Super Desition and ArcGis software was used. However logistic regression is a multivariate statistical technique predictor for the dependent variable that is modes of zero and one with lack of occurrence or the event (eg landslide) are. In this method, regression relation the variables not to linear and logistic curve is S-shaped. In The models are estimates in the range of zero to one that the numbers are nearly zero, indicating less likelihood of preparing and numbers are nearly one indicates higher risk. In the models was runed by using the Edrisi and ArcGis software.
Results and discussion
In the Analytic Network Process method, for runing a three-layer model consists of, goal, criteria, Alternatives was designed. After runing paired comparisons between elements and clusters the priority of the danger classes based on their significance was determined and the coefficients of the factors showed that the land use factor has the maximum effect in occurrence of the landslides if the area.The zoning of map were classified in five classes of very high to very low risk class. In the logistic regression method the eveletion factor became known as the most influential factor in the occurrence of the landslides of the area .For Testing Accuracy of the model , three-Statistical indexs were used that includs Chi Square , Pseudo R Square, ROC. The Value of Chi Square is 1657/0673 and value of Pseudo R Square is 0/5677 and the ROC value is 0/9726 that showed accuracy of the model. And finaly two listed methods were compared with each other and the best model was selected and introduced.
The Result:
The results showed that among eight factors effective factors, Land use, Elevation and Aspect have a greater role in the occurrence of landslides. Also comparison of the degree of fit between landslide distribution and zoning maps of the mentioned method showed that, the analytic network process with 67/33% fitness has the better performance than the logistic regression in Identiting risk areas in the study area. Thus, the two statistical methods used in this study was obtained from the logistic regression model and the ANP model (Eq. 2) selection to as the best model was introduced. Also, according the results of landslide hazard zonation in the study area using the two methods mentioned 39/19% of the total area of landslides is very high risk.ارزیابی پتانسیل وقوع زمینلغزش در منطقهای که به دلیل وضعیت جغرافیایی و ساختوسازهای انسانی مستعد لغزش میباشد ضروری مینماید. سد مخزنی قلعه چای عجبشیر، یکی از این نوع نواحی میباشد. در این مطالعه، جهت بررسی پتانسیل وقوع زمینلغزش، روشهای تحلیل شبکه ( ANP ) و رگرسیون لجستیک مورد ارزیابی قرار گرفت . جهت این مطالعه از تصویر TM، 2011 ماهواره لندست استفاده شد. فاکتورهای مؤثر وقوع زمینلغزش ( شیب، جهت دامنه، لیتولوژی، کاربری زمین، فاصله از گسل، فاصله از رودخانه، فاصله از جاده، طبقات ارتفاعی ) در محیط GIS آماده و سپس با لایه پراکنش زمینلغزشها قطع دادهشده و نقشههای پهنهبندی خطر زمینلغزش در روشهای فوق تولید شد. نتایج نشان داد که فرآیند تحلیل شبکه نسبت به روش رگرسیون لجستیک عملکرد بهتری را در بررسی پتانسیل وقوع زمینلغزش در منطقه موردمطالعه دارد همچنین تفسیر ضرایب نشان داد که ، کاربری اراضی، طبقات ارتفاعی، جهت دامنه، نقش مهمی در وقوع زمینلغزش دارند. و با استفاده از نقشه پیشبینی احتمال وقوع زمینلغزش، منطقه به پنج گروه حساسیت تقسیم: بسیار پایین، پایین، متوسط، بالا، بسیار بالا.https://www.geomorphologyjournal.ir/article_78054_a22d9204f4af59e9d8f1dbb2aca4b150.pdfانجمن ایرانی ژئومورفولوژیپژوهشهای ژئومورفولوژی کمّی225194245320181118The effect of water spreading system on sediment particle size distribution (case study: Zahab Plain Catchment, Kermanshah)تأثیر سامانه پخش سیلاب بر توزیع دانهبندی رسوب (مطالعه موردی: حوضه آبخیز دشت ذهاب کرمانشاه)819278055FAکاظمنصرتیزینبمحمدیعلی اکبرنظری سامانیJournal Article20181118Introduction
Erosion and sedimentation are highly important in geomorphological studies. Accelerated soil erosion causes adverse agronomic, ecologic, environmental, and economic effects both on-site and off-site. The main on-site consequences involve the reduction in soil productivity, while the off-site consequences are mostly due to the sediment and sediment-associated chemicals transported from the source into surface waters. Nowadays most researchers investigate the sediment particle size distribution in river systems from different standpoints in order to understand the hydrodynamic behavior of suspended sediments and to calibrate transfer models and sedimentation in flood plains and channels. Water spreading system is a mechanical method to control flood in the plain in order to recharge of aquifer and increase the groundwater level. Suspended materials in floods can be changed the sediment and soil texture and structure and increase the depth and fertility of soils on which these floods flow. Hence, it is necessary to investigate these changes and their process so that an appropriate method for increasing the efficiency of these plans can be presented. Despite the importance of sediment particle size distribution, no studies on this subject have been done in Iran. Therefore, the main objective of this study was to investigate the effect of water spreading system on sediment particle size distribution watershed, alluvial fan, and water spreading system of Zahab Plain.
Methodology
In order to study spatial variation of sediments particle size distribution four samples were taken from the sediments of each of the 9 water spreading channels, and 5 samples were taken from the sediments of the main valley, active channel and inactive alluvial fan. The sediment particle size distributions were determined using dry sieve method. The particle sizes in different site sampling were compared using one-way ANOVA. Finally, the within comparison were done using Tukey-HSD method. test was used.
Results and discussion
The distribution of coarse sediment particles
Multiple comparisons with Tukey-HSD method indicated that the groups have a significant difference. The amount of sediment particles with diameters of 16, 4, and 2 mm in the flood distribution channels are approximately zero due to the existence of stilling basin prior to floodwater spreading channels. On the other hand, due to the smallness of the basin, the steep channel, the steep-walled valley, lack of vegetation, dry climate and the low depth of soil in the upstream basin can be considered as the main factors increasing erosion and coarse sediments’ particles in the main valley, active and inactive channels. The lack of significance for the diameter of 1 mm can be attributed to the increase of this diameter in floodwater spreading channels as a result of stilling basin and meeting the relative conditions for the sedimentation of particles in the channels. On the other hand, the decrease in the number of sediment particles in the main valley and the active basin can be attributed to the direct relation of particle size distribution with the portability of sediment flows.
The distribution of fine sediment particles
Multiple comparisons showed that the amount of sediments in diameters 0.5, 0.25, 0.063 mm was significant. Only in diameters larger than 0.063 mm it was not significant. The results showed the increase of average in floodwater spreading channels due to the existence of stilling basin prior to channels which led to the sedimentation of most coarse sediment particles in them and the movement of particles not sedimented in the stilling basin toward the channels. Since in the main valley and the active basin as the particles become smaller they are more easily transferred with the least amount of water force because of their small weight, they show no conspicuous change.
Conclusion
The present research was done with the aim of investigating the spatial variation of sediment particles in the distribution basin of Zahab Plain. It can be concluded from the results that particle size is due to the hydraulic force of floodwater. Considering the slope and the power of water flow in the main valley and the active channel and on the other hand the existence of stilling basin and diversion channel toward the spreading project, the sediments’ particle size will certainly vary in different parts. Hence, it can be said that floodwater spreading operations have led to the reformation and lightness of soil of the spreading project. Therefore, the spread of floodwater and sedimentation of suspended materials in floods in rocky and coarse sediment lands of alluvial fan can lead to changes in the tissue and structure and increase the depth and fertility of soils on which these floods flow turning them into suitable lands.بررسی ویژگیهای فیزیکی رسوبات از موضوعات مهم در مطالعه فرسایش و رسوب است. سامانه پخش سیلاب یک روش ساده برای کنترل سیلاب و استحصال آب از طریق تغذیه سفرههای آب زیرزمینی است. بدین ترتیب هدف از این مطالعه ارزیابی آماری تأثیر سامانه پخش سیلاب دشت ذهاب کرمانشاه بر توزیع دانهبندی رسوب میباشد. به این منظور از رسوبات کف هر یک از نه کانال پخش سیلاب چهار نمونه و دره اصلی حوزه آبخیز، آبراهه فعال و بخش غیرفعال مخروط افکنه پنج نمونه به میزان دو کیلوگرم رسوب برداشت شد. کلیه نمونهها با استفاده از روش الک خشک دانهبندی شده و درصد فراوانی آنها (در قطرهای مختلف) تعیین گردید. سپس با استفاده از تحلیل آماری درصد فراوانی نمونهها با قطرهای مختلف در بخشهای مختلف مخروط افکنه و سیستم پخش سیلاب مقایسه و موردبررسی قرار گرفت. نتایج نشان داد توزیع اندازه ذرات رسوب در قطرهای (16، 4، 2، 5/0، 25/0، 063/0 میلیمتر) در حوزه آبخیز و بخشهای مخروطافکنه و سیستم پخش سیلاب کاملاً معنیدار (05/0>p < /span>) میباشد، تنها توزیع اندازه رسوب در قطر1 و <063/0 میلیمتر معنیدار نیست (05/0https://www.geomorphologyjournal.ir/article_78055_640105bca8a4f6a03586af718a3841a8.pdfانجمن ایرانی ژئومورفولوژیپژوهشهای ژئومورفولوژی کمّی225194245320181118Assessment of qualitative changes in Urmia quaternary plain groundwaterبررسی تغییرات کیفی آبهای زیرزمینی واقع در رسوبات کواترنری دشت ارومیه9311078056FAامیرحسینکوکبی نژاد قزوینیوحیدمحمدنژادمحمدباقرسلیمانیJournal Article20181118In this study, the quality of Urmia plain groundwater in 1380 and 1393 are discussed and analyzed. The main purpose of this study is to investigate the temporal and spatial changes in groundwater quality, mapping elements for the study time period and comparison of the elements in the waters with the region and international standards. Statistics of meteorological data as well as Urmia plain groundwater quality data, (20 sample wells), (1380-1393), are the most important data in this study. 1:25000 topographic maps and 1:100000 geological maps and GIS software are important used tools in this paper. The methods of study analysis are based on geostatistical methods and analysis of Wilcox, Piper and Schoeller graph. The results show that in 1380 the maximum of chloride is in the center of plains, but in 1393 the maximum amount of it, is pasted to east of plain (west margin of Urmia lake). In 1380, Sodium is high in the north, center and south but in 1393 some of these values is in the East and Northeast. Calcium ions in 1393 in comparison to 1380, has increased in east part of plain. In 1380 maximum bicarbonate ions (2.9) is seen in the west of plain while in 1393 maximum of this ion (2.10) has been seen in the eastern half of plain. The maximum electrical conductivity (EC) of groundwater in 1380 at about 1656 cm/ micromhos is in the center and northwest of plain. While in 1393 it was 2300 units and more can be seen in the east of plain. The total hardness of the water in 1380 from center of plain moved to the east of plain in 1393. In general, most of the elements during the study period in terms of time and place have changed. Despite the particular circumstances in the region, the quality of groundwater in the triple use especially in drinking use, is good.در پژوهش حاضر به بررسی و تجزیهوتحلیل کیفیت آبهای زیرزمینی دشت ارومیه طی سالهای 1380 و 1393 پرداختهشده است. هدف عمده و اصلی در این پژوهش، بررسی تغییرات زمانی و مکانی کیفیت آبهای زیرزمینی دشت ارومیه، تهیه نقشه پهنهبندی عناصر برای دوره زمانی موردمطالعه و مقایسه میزان عناصر موجود در آبهای منطقه با استانداردهای موجود است. آمار و دادهای هواشناسی و همچنین کیفیت آبهای زیرزمینی دشت ارومیه، به تعداد 20 چاه نمونه (1380-1393)، از مهمترین دادههای این تحقیق به شمار میروند. نقشههای توپوگرافی 25000 و نقشههای زمینشناسی 100000 و نرمافزارهای GIS مهمترین ابزار کار به شمار میروند. روش تجزیهوتحلیل مبتنی بر روشهای زمینآماری و تحلیل نمودارهای ویلکوکس، پایپر و شولر است. نتایج نشان میدهد در سال 1380 حداکثر گسترش کلراید در بخش مرکزی دشت ولی در سال 1393 مقادیر حداکثر به شرق دشت یعنی به سمت دریاچه ارومیه گسترش پیداکرده است. سدیم در سال 1380 در شمال و مرکز و تا حدی جنوب بالاست ولی در سال 1393 این مقادیر در شرق و شمال شرق زیاد است. مقادیر یون کلسیم نیز در سال 1393 نسبت به سال 1380 در شرق دشت افزایش پیداکرده است. یون بیکربنات در سال 1380 به میزان حداکثر 2/9 در غرب دیده میشود در حالی این میزان در سال 1393 به 2/10 و نیمه شرقی افزایش پیداکرده است. حداکثر هدایت الکتریک آبهای زیرزمینی دشت ارومیه در سال 1380 در حدود 1656 میکروموس در سانتیمتر و در مرکز و شمال غرب دشت قرار دارند. درحالیکه در سال 1393 این میزان 2300 واحد شده و بیشتر در شرق دشت ارومیه مشاهده میشود. میزان سختی کل آب نیز از بخش مرکزی در سال 1380 به بخش شرقی دشت در سال 1393 منتقلشده است. بهطورکلی اغلب عناصر در طی دوره مطالعاتی به لحاظ زمانی و مکانی دچار تغییرات شدهاند. ضمن اینکه باوجود شرایط خاص در منطقه، آبهای زیرزمینی به لحاظ مصارف سهگانه بهویژه در بخش شرب، از کیفیت مناسبی برخوردار است.https://www.geomorphologyjournal.ir/article_78056_81470773881788644b73b0e6db20da8c.pdfانجمن ایرانی ژئومورفولوژیپژوهشهای ژئومورفولوژی کمّی225194245320181118The Compare of grading criteria in Coarse ripple Mark on the windward and leeward slopes (Case Study: Hassan Abad erg in Bafg)مقایسه شاخص های دانهبندی ذرات دامنه روبه باد و پشت به باد ریپل مارک های درشت (مطالعه موردی:ارگ حسن آباد شهرستان بافق)11112078057FAفاطمهکارگرانسعیدهکلانتریمحمدجوادقانعیمهدیتازهJournal Article20181118Introduction:
About 36 percent of Earth's land surface covered arid and semi-arid lands. 19 percent of these levels is dry completely and without plant life. In Iran, One-third to one-quarter of surfaces is covered with running sands (Ekhtesasi, 1375, 97).
So far, there has been a lot of discussion for identification of appropriate indicators for rapid assessment of Intensity and the extent of degradation in arid lands. Using of geomorphologic Indices Due to the It was possible to measure as a quantity and also it has a direct relationship to processes of erosion and sedimentation, is very important. Ripple mark Are waves that formed by the wind blowing on sandy areas. When wind blows on the sandy ground, Makes the movement of sand And therefore are formed Ripple marks (Montagne and Thomas, 2002, 806). Whatever Particle diameter is larger represents the region's severe winds, so larger particles is, more their resistance against wind erosion (welfare, 1388, 16).
Ghanei Bafghi and Yar Ahmadi) 1390) evaluated the relationship of sand dunes Aggregation With direction of erosive Wind In Hassan Abad Bafg Erg. The main objective of the plan is providing the index In addition to the existing indices to determine erosive Wind direction in the area that showed Erosive wind direction is Northern sector.
Methodology:
In Hassan Abad Bafg erg, It can be seen Two types of ripple mark One of them is small ripple mark That dispersed all over erg And other coarse Ripple marks That's just In between hills, In places where the wind due to Canalization Has High speed, For this study First, with the help of satellite images Investigated dune Has been determined And by visiting the study area has identified coarse Ripple marks (Figure 1).According to purpose of the study, Has been done Sampling from windward Slopes and leeward Slopes sediments of Ripple coarse marks.
This sampling as completely random and was conducted on 36 coarse ripple mark. These 1000g samples was held in plastic bags And for analysis was transferred to the laboratory. In the laboratory samples was passed a series of sieves 2, 1, 5/0, 25/0, 125/0, 063/0 mm, For 10 minutes, by shakers. Due to the Samples were without aggregate particles of all samples was sieve by. Dry method And Samples Weight measured in each sieve carefully.
The obtained data were inserted in the SPSS software and in order to assessment of Gradation difference in both Slopes of Ripple mark used t- test.
Results and discussion:
This research compares the Gradation Indices of windward and leeward slopes Particles coarse ripple marks in, Hasanabad Bafg erg. The results of Statistical Summary in Sample weight Showed that Particle diameter in windward slopes is greater than the leeward slopes. T-test results of sediments Weight in these two slopes showed that coarse ripple mark not significant. Particles Weight on the 2 mm sieve in confidence level of 5 percent, the rest of the particles weight on sieves 1, 5/0, 25/0, 125/0, 063/0 mm (Less than 2mm), were significant in confidence level of 5 percent; because it is the low weight of the particles. The results of t-test values d_10, d50, d90 Between the sediments Windward slopes and leeward slopes coarse ripple mark showed that At 5% level There is a significant difference between the two slopes sediments, Also, Because average of particles windward slopes Is greater than the leeward Slopes, Particle diameter windward Is Larger than the leeward.
Conclusion:
According to folk formula and obtained information was observed particles of windward Slopes Has a high SORTING And particles of leeward Slopes has a weak Sorting.
The cause of which is Light sediment transport by the wind from windward Slopes and their associations in leeward Slopes and mixing of sediments in the area.
In the other words Due to particles carried from the windward Slopes Uniformity and SORTING In this area is more and due to Carried particles accumulation from the windward Slopes To leeward Slopes and mixture of particles Uniformity and particles of SORTING In this area is less. It can be concluded Particle diameter in windward Slopes Have more sorting to leeward and the results of t-test sorting according to Folk formula shows in Level of 99% there is significant differences among sediments.این پژوهش بهمنظور مقایسه شاخصهای دانهبندی رسوبات دامنه رو به باد و پشت به باد ریپلمارکهای درشت در ارگ حسنآباد بافق، انجام شد. ابتدا از رسوبات موجود در هر یک از دو دامنه ریپلمارکهای درشت نمونهبرداری صورت گرفت سپس دانهبندی هر یک از نمونهها، بر اساس روش الک خشک، انجام گرفت دادهها بهدستآمده به نرمافزار SPSS وارد شد و بهمنظور بررسی معنیدار بودن اختلاف بین متغیرها از آزمون t-test، استفاده شد همچنین با استفاده از نرمافزار GRADISTAT مقادیر، ، و برای محاسبه میانگین قطر ذرات در دو دامنه استفاده شد. با رسم نمودار دانهبندی تجمعی در مقیاس فی پارامترهای برای محاسبه فرمول فولک و بررسی جورشدگی رسوبات محاسبه شد. نتایج این تحقیق نشان داد متوسط وزن ذرات بر روی الکهای درشتتر (1 و 5/0 میلیمتر) در دامنه رو به باد (به ترتیب 47/371، 30/243 گرم) بیشتر از این مقدار در دامنه پشت به باد (به ترتیب 87/129، 29/97) است. اختلاف معنیداری بین وزن ذرات روی الکهای کمتر از 2 میلیمتر در سطح 5 درصد مشاهده میشود. همچنین بین مقادیر ، و در رسوبات دامنه رو به باد و رسوبات دامنه پشت به باد ریپلمارکهای درشت در سطح 5 درصد اختلاف معنیدار وجود دارد. محاسبه جورشدگی به روش فولک برای ذرات دو دامنه نشان داد میانگین شاخص فولک ذرات دامنه رو به باد 6/0 و پشت به باد 1 به دست آمد و لذا ذرات دامنه رو به باد دارای جورشدگی نسبتاً بالا و ذرات دامنه پشت به باد دارای جورشدگی ضعیف میباشند و بین جورشدگی رسوبات دو دامنه اختلاف معنیدار در سطح 99 درصد مشاهده شد.https://www.geomorphologyjournal.ir/article_78057_ca3bee1c7591a70055c255b314a6b82f.pdfانجمن ایرانی ژئومورفولوژیپژوهشهای ژئومورفولوژی کمّی225194245320181118Assess the potential of land subsidence and its related factors(Case study: Plain Saidan Farouk MARVDASHT(ارزیابی پتانسیل فرونشست زمین و عوامل مؤثر بر آن ( مطالعه موردی: دشت سیدان فاروق مرودشت)12113278058FAمحمدابراهیمعفیفیJournal Article20181118In recent years due to excess exploitation of ground water in fertile plains, land subsidence has become one of the main natural disasters. Neglecting such a phenomenon can cause severe irreparable damages. Accordingly, it is indispensible to assess the potential of fertile lands for subsidence. This study evaluates the potential of land subsidence and effective factors in Farough - Seydan fertile land in Marvdasht. First, the 11 piezometers of 14 available piezometers in statistical period of 1374 – 1378 are evaluated. And the empirical relationship of Lamb- Whitman is used to have the map of land subsidence risk. Hence, after Thiessen networking some parameters are prepared such as primary osteoporosis, the coefficient of compression capacity, the initial thickness of intended layers,
effective stress the primary and secondary, Raster layers of thickness of saturated area between raw water table and hypothetical layer, initial pore water pressure, changes in effective stress, probable subsidence and its risk .The data show that there are two zones with extra high risk ( 5.57 percent of the plain) and high risk ( 19.76 percent of the plain) in which two factors are the most effective ones; the density of the clay layers and excessive water withdrawals.During the period of 1375 – 1388 there were 1700 agricultural wells in the plain that caused the drop of 17.96 meter of underground water. This, in turn paves the way for the high density of clay layers and land subsidence.فرونشست زمین بهعنوان یکی از مخاطرات طبیعی در سالهای اخیر با افزایش بهرهبرداری بیشازحد از آبهای زیرزمینی بهعنوان یک مسئله اساسی در دشتهای حاصلخیز کشور مطرحشده است. بیتوجهی به اینگونه پدیدهها میتواند خسارت جبرانناپذیری را به بار آورد. بنابراین ارزیابی پتانسیل و میزان استعداد دشتهای حاصلخیز نسبت به پدیده فرونشینی امری ضروری است. در پی همین ضرورت، پژوهش حاضر به ارزیابی پتانسیل فرونشست زمین و عوامل مؤثر بر آن در دشت حاصلخیز فاروق-سیدان شهرستان مرودشت میپردازد. جهت انجام این پژوهش، ابتدا دادههای مربوط به 11 پیزومتر از 14 پیزومتر موجود در دروه آماری 1388-1374 بررسی و بهمنظور تهیه نقشه خطر فرونشست از رابطه تجربی لامب-ویتمن استفاده شد. بدینصورت که بعد از شبکهبندی تیسن هر پیزومتر، پارامترهای پوکی اولیه، ضریب توانایی فشرده شدن، ضخامت اولیه لایههای موردنظر، تنش مؤثر اولیه و ثانویه برآورد و لایههای رستری ضخامت منطقه اشباع بین سطح ایستابی اولیه و سطح اساس فرضی، فشار آب منفذی اولیه ، تغییرات تنش مؤثر، فرونشست احتمالی و خطر فرونشست تهیه شد. بررسی دادهها نشان داد که در دشت فاروق- سیدان، دو منطقه با خطر فرونشست خیلی زیاد(57/5 درصد از مساحت دشت) و زیاد (76/19 درصد از مساحت دشت) وجود دارد که عوامل تراکم و فشردگی میان لایههای رسی و برداشت بیرویه آبهای زیرزمینی مؤثرترین عوامل هستند. در طول دوره 1388-1375، باوجود 1700 حلقه چاه کشاورزی در سطح دشت باعث افت 96/17 متری آب زیرزمینی شده و شرایط را جهت فشردگی میان لایههای رسی و فرونشست زمین فراهم کرده است.https://www.geomorphologyjournal.ir/article_78058_314f4127a8cfeb57dc63757f33360135.pdfانجمن ایرانی ژئومورفولوژیپژوهشهای ژئومورفولوژی کمّی225194245320181118Investigation of morphometric characteristics of gullies and Relationship between morphometric parameters and soil characteristicsبررسی ویژگیهای مورفومتری خندقها و ارتباط آن با ویژگیهای خاک13314578059FAمرضیهمکرمعلیرضامحمودیJournal Article20181118Introduction
Gullies are an important part of the soil erosion process and their occurrence and development may cause serious problems to a region s economy. They erode agricultural lands and act as potentially important sediment sources for rivers and reservoirs. Gully processes have been studied from a range of viewpoints (e.g. hydraulics, agricultural and forest engineering, hydrology and geomorphology) but despite a wealth of information collected, particularly in the last 20-30 years, many problems of morphology remain poorly known. Attempts to define gullies and their typology reflecta discouraging diversity of opinions. As far as gully spreading is concerned some authors believe that because of the scarcity of data there is an insufficient knowledge of gully development. Recent studies indicate that (1) gully erosion represents an important sediment source in a range of environments and (2) gullies are effective links for transferring runoff and sediment from uplands to valley bottoms and permanent channels where they aggravate off site effects of water erosion. In other words, once gullies develop, they increase the connectivity in the landscape. Many cases of damage (sediment and chemical) to watercourses and properties by runoff from agricultural land relate to (ephemeral) gullying. Consequently, there is a need for monitoring, experimental and modelling studies of gully erosion as a basis for predicting the effects of environmental change (climatic and land use changes) on gully erosion rates. In this respect, various research questions can be identified.
Methodology
The study area is located in North of Darab province and south of Fasa province, southwest Iran. Surface soil samples (0-20 cm and 20-60 cm) were sampled from gully of the study area, air-dried and sieved (<2 mm) for laboratory analyses. Then some physical and chemical properties were determined. Particle size distribution was determined by the method of Rowell (1994). Calcium carbonate equivalent was determined by acid neutralization (Salinity Laboratory Staff, 1954). Organic carbon was determined by the method of Nelson and Sommers (1982). The soil pH was determined in saturated paste (Salinity Laboratory Staff, 1954). Electrical conductivity was determined in the saturated extract (Salinity Laboratory Staff, 1954). Cation exchange capacity (CEC) was determined using sodium acetate at a pH of 8.2 (Chapman, 1965). Available K was determined by the method of Pratt (1965). Then K was measured on all filtrated extracts by Corning 405 flame photometer. Plant available soil phosphate was measured by the method of Olsen et al. (1954). Also In order to understand the factors influencing gullying a detailed inventory of the gullies (number, density, size, type, location in the drainage basin etc.) was completed. Topographical maps and aerial photographs have been used to provide this information as in India (Haigh, 1984), Tadjikistan (Ahmadov, 1977), Russia, Bielorussia, Ukraine(Kosov and Kostantinova, 1972), Lesotho (Nordstrom, 1988), Brasilia (De Oliveira,1990), Israel (Seginer, 1966), and Romania (Motoc et al., 1979). The inventory of gullies in this study used topographical maps at a scale of 1 : 25,000. For each case the following variables were taken into consideration: number of gullies, length, maximum width and maximum depth, gully orientation, depth of head cat and so on. Finally for determination of relationship between gully characteristics and soil characteristics used regression.
The general purpose of multiple regressions is to learn more about the relationship between several independent or predictor variables and a dependent or criterion variable. The general form of the regression equations is according to Eq. 1:
Y=A0 + A1X1 +A2X2 + … +bnXn (1)
Where Y is the dependent variable, A0 is the intercept, A1. . .bn are regression coefficients, and X1– Xn are independent variables referring to basic soil properties.
Results and discussion
The results show that there are high correlation between the volume of gully and depth of gully. Also the correlation between volume of gully and soil properties (sodium, potassium, magnesium, chlorine, zinc, copper, iron, bicarbonate and organic carbon) showed that by reducing the amount of organic matter (OC) and bicarbonate (CC) increase volume of gully. So that the OC with a correlation coefficient CC -0.987** and -0.987** are in reverse correlation with the Volume of gully.
Conclusion
In this study it was found that by reducing soil nutrient increases the size of the gully in the study area. It was also found that increasing human activities in areas where soils are susceptible to erosion, gully expansion will increase.مهمترین عامل بررسی مناطق خندقی وقوع فرسایش و تخریب زیاد خاک است. با توجه به اهمیت بررسی خندقها هدف از این مطالعه بررسی خندقهای واقع در جنوب شهرستان فسا و شمال شهرستان داراب میباشد. خندقهای واقع در این دو منطقه ازنظر ابعاد با یکدیگر متفاوت هستند بهطوریکه خندقهای واقع در جنوب شهرستان فسا دارای ابعاد بزرگتری در مقایسه با خندقهای واقع در شمال شهرستان داراب میباشد. برای این منظور ویژگیهای مورفومتری خندقها که شامل طول، عرض، عمق و ارتفاع میباشد اندازهگیری شد. همچنین بهمنظور بررسی ارتباط بین ویژگی مورفومتری خندق و ویژگیهای خاک پارامترهای سدیم، پتاسیم، منیزیم، روی، کلر، آهن، منگنز، کربن آلی و بیکربنات اندازهگیری شد. نتایج حاصل از رگرسیون خطی چندگانه نشان داد که حجم خندق با عمق خندق ارتباط مستقیم و با میزان مواد آلی رابطه معکوس دارد. بنابراین با کاهش میزان مواد آلی در خاک فرسایش آبی در منطقه افزایش مییابد و زمینه برای فرسایش خندقی که پیچیدهترین و مخربترین نوع فرسایش آبی است، فراهم میشود.https://www.geomorphologyjournal.ir/article_78059_2d9d8c02281a1e13edbe828ba0eaa0d4.pdfانجمن ایرانی ژئومورفولوژیپژوهشهای ژئومورفولوژی کمّی225194245320181118Study of river morphology changes and its role in erosion and sedimentation using HEC-RAS (Case Study: Khorramabad river-Doab Veysian, Lorestan)بررسی تغییرات مورفولوژی رودخانه و نقش آن در فرسایش و رسوبگذاری با استفاده از HEC-RAS (مطالعه موردی: رودخانه خرمآباد – دوآب ویسیان)14616378060FAعلیرضاایلدرمیآزادهشیخی پورJournal Article20181118Rivers of the most important factors affecting geomorphological processes and cycles of erosion, till now studies extensively on morphological changes in rivers and the factors affecting them are taken. The aim of this study was to study morphological changes Khorramabad River - Doab Veysian and factors contributing to the change geometry and create relationships between them. In order Estimated Discharge with different return periods from Discharge Chamanjir station and Doab Veysian statistical period (1335-1334) and (1392-1391) was used. After completing the Statistics by software SMADA statistics maximum discharge Chamanjir station and Doab Veysian were fitted with different statistical distributions and Statistics for the Log Pearson Type III distribution was the best fit. To simulate the hydraulic flow in this research, according to the information available, was considered unsteady flow. For this purpose, after entering geometric data and flow data,the boundary conditions for a range of upstream, hydrograph and for limiting downstream, rating curve was considered. Then, execution models and the results were extracted. Sediment simulation was done at a later stage. For this purpose along the river Khorramabad - Doab Veysian, four samples of the materials were taken from the river bed and banks. Samples taken place, due to changes in grain size distributions, changes in slope (topography) and connecting tributaries of the main river was important. Accordingly, in Chamanjir station, Veysian-e olya, Shurab-e Sofla and Doab Veysian station According to uniform materials, samples were taken. After the harvest, samples for gradation testing were transferred to Technical and Soil Mechanics Laboratory. After this stage, sediment data entered into the application and boundary conditions for a range of upstream and downstream for the period discharge - sediment curve were selected. Ruby equation was used to determine fall velocity and sediments transport. To perform simulations of sediment need to enter the data was unsteady quasi After entering this data and the boundary condition for a range of upstream flow series and discharge - scale curve interval for downstream, Calculation of the simulation of sediment is done and results were extracted. Since some of the sedimentary particles fall velocity calculation methods such as Ruby need to water temperature, information on water temperature in part due to the Quasi unsteady flow input into the software. Sediment boundary condition as a sediment rating curve gives the relationship between flow and sediment discharge, the software was defined. According to a survey carried out and it was found that due to the high number of input data that To fully understand and carry out successful model calibration, sensitivity analysis will be necessary to model parameters. At this stage in order to examine the relationship between geometric data and outputs hydraulic the resulting hydraulic model HEC-RAS, the proportion of simple linear regression, grade 2, grade 3 and was exponential. After heterogeneity test data, Normal set of original data (each variable) and determine correlations between variables, Regression equations, using the software SPSS, was determined and the relations between the two variables (independent variable and dependent variable) with the highest coefficient of determination, the lowest standard error and the lowest level of significance had was chosen as a suitable relationship. The results of the regression relationship between the dependent variable discharge (Q) and the independent variable width (W), hydraulic depth (D), the flow cross section (A) and flow velocity (V) based on a significant level values, the coefficient of determination and error standard indicated that Simple linear equations (grade 1) often has a R2 relatively high, SE low and P-value high. In grade 2 and 3 models due to a problem is linearity, these models were not credible. In addition, grade 2 and 3 models both in terms of Significant level and standard error are not credible. Thus, the reasons are not linear exponential model, P-value less than 1% and standard error is less than the other models, suitable model are introduced. Regression relationship between the dependent variable sediment capacity (SC) nd independent variables shear stress (SH), discharge (Q) and flow velocity (V) based on the P values, the determination coefficient and standard error were investigated. The coefficient of determination obtained in the exponential function for V, Q, SH Grade 2 and grade 3 lower values and regression equations and simple linear regression function further and P-value is seen as the values of all variables at 1% (99% confidence interval) are significant. Also, in the function variables have the lowest standard error and significance level than linear, Grade 2 and Grade 3 so are the appropriate models for the studied river. In grade 2 and 3 models due to a problem is linearity, these models were not credible. In addition, grade 2 and 3 models both in terms of Significant level and standard error are not credible. Thus, the reasons are not linear exponential model, P-value less than 1% and standard error is less than the other models, suitable model are introduced. According to the Manning coefficient, three parameters water surface width, velocity and flow depth review and to obtain the results of the model in sensitivity analysis, with regard to the accuracy of 80%, The number sections that sensitivity percentage was more than 20%, It was considered as an error. The results of the study showed that sediment transport capacity in the range under study of Khorramabad river-Doab Veysian is variable. Results, Sediment values are calculated by By equation Ackers-White as the appropriate relationship between the independent variables showed that the sediment capacity is more dependent on the discharge. This means that runoff greatest impact in changing the morphology of the river. The amount of sediment capacity and shear stress is directly proportional to the flow velocity This means that with increasing shear stress and flow velocity, sediment transport capacity is also increasing And also by increasing sediment transport capacity, shear stress and flow velocity increases. According to the above cases and the particles size of the studied river it was found that in the first range (Chamanjir station), Sedimentation, in the second range (between two stations), erosion and the third range (Doab Veysian station), sedimentation as well as occurs.تغییرات مورفولوژیک رودخانهها از مهمترین عوامل مؤثر در فرآیندهای ژئومورفولوژیک چرخه فرسایش میباشند. هدف از این تحقیق، مطالعه تغییرات مورفولوژی رودخانه خرمآباد - دوآب ویسیان و بررسی عوامل مؤثر در تغییر شکل هندسی و ایجاد روابط بین آنها است. بهمنظور برآورد دبی با دوره بازگشتهای مختلف از نرمافزار SMADA جهت برازش دادهها استفاده شد. پس از واردکردن دادههای هندسی و جریان، شرایط مرزی برای بازه بالادست، هیدروگراف جریان و برای بازه پاییندست، منحنی سنجه تهیه شد. در طول مسیر رودخانه خرمآباد - دوآب ویسیان، چهار نمونه از مصالح بستر و کنارههای رودخانه برداشت و تغییرات دانهبندی رسوبات، وضعیت شیب و اتصال شاخههای فرعی مهم به رودخانه اصلی تعیین و نمونهها برداشت و آزمایشات دانهبندی صورت گرفت . دادههای رسوب به نرمافزار وارد و از رابطه (Ruby) در تعیین سرعت سقوط و انتقال رسوبات و دمای آب استفاده شد. بهمنظور بررسی ارتباط بین دادههای هندسی و هیدرولیکی از خروجی مدل هیدرولیکیHEC-RAS ، به بررسی تناسب روابط رگرسیونی خطی ساده، درجه 2، درجه3 و نمایی پرداخته شد. با تعیین میزان همبستگی بین متغیرها، روابط رگرسیونی، با استفاده از نرمافزار SPSS ، از بین روابط تعیینشده بین دو متغیر) متغیر وابسته و مستقل) رابطهای که بیشترین ضریب تعیین، کمترین خطای استاندارد و کمترین سطح معنیداری را داشت به منزله رابطه مناسب انتخاب شد. نتایج حاصل از اجرای مدل نشان داد که ظرفیت حمل رسوب در بازه موردمطالعه رودخانه خرمآباد - دوآب ویسیان متغیر میباشد. مقادیر رسوبات محاسبهشده بهوسیله رابطه ایکرز- وایت بهعنوان مناسبترین رابطه نشان داد از بین متغیرهای مستقل ظرفیت رسوب بیشتر به دبی جریان وابسته است. اندازه ذرات رودخانه موردمطالعه مشخص شد که در بازه اول (ایستگاه چمانجیر)، رسوبگذاری، در بازه دوم (بین دو ایستگاه)، فرسایش و در بازه سوم (ایستگاه دوآب ویسیان)، نیز رسوبگذاری رخ میدهد.https://www.geomorphologyjournal.ir/article_78060_8c8bab8a3946fade1d663a610e9320b6.pdf