دانشگاه شهرکردپژوهش آب ایران2008-123512220180622Experimental study of the effect of the parallel and flake ripple bed forms on the bed shear stressبررسی آزمایشگاهی اثر شکل بستر شکنج در دو حالت موازی و پولکی بر تنش برشی بستر1810581FAحسینصمدی بروجنیپریملکیروح الهفتاحی نافچی0000-0002-7309-3514داریوشملکیJournal Article20140526Interaction between water flow characteristics and bed erodibility plays an important role in sediment transport process. In order to reach stability, rivers with deposition or bottom erosion make different forms in the bed .The bed forms create extra resistance, which is called the bed resistance. The mutual interaction between the flow and the erodible bed through sediment transport phenomena in a sand-bed channel causes a variety of bed forms. Starting with ripples and gradually increasing in shear stress or water velocity, dunes, washed out dunes, flat bed, anti-dunes, and standing waves are formed. The most common boundary conditions in alluvial rivers are the mobile beds covered with Ripple and Dune. These forms, in many alluvial systems, play a critical role in contrast between the flow, discharge of sediment and morphology of bed. One way to identify the behavior of the rivers is to study the structure and the formation of bed forms within them. Ripples are among the smallest of the bed forms. The longitudinal cross-sections of ripples are usually asymmetrical. The upstream face of ripple is long and has a gentle slope, and the downstream face is short and steep. The height of ripples is usually between ۰.۵ cm and ۲ cm, but not more than ۵ cm. The wave lengths normally do not exceed to ۳۰cm, and they are usually within the range of ۱ cm to ۱۵ cm. Some ripples that form in deep-water regions are symmetrical. Ripples are the smallest of the bed configurations. They are related to physical parameters near the river bed and have little correlation with the water depth. Their occurrence is the result of the unstable viscous layer near the boundary. They can form in both shallow and deep water. In plan, they either are parallel to each other or have a shape like fish scales. With increasing the flow velocity, the plan form of the ripples gradually develops form straight line to curves and then to a pattern like fish scales, symmetrical or unsymmetrical Resistance is a function of the geometrical dimensions of the bed forms and depth of water. Estimating of the flow resistance is one of the most important matters in planning, designing and operating of water resources projects, including water transfer and river system management. In this research, the effects of two different types of ripples (parallel and flake shape) on the hydraulic characteristics of flow were experimentally studied. The experiments flume located at the hydraulic laboratory of Shahrekord University, Iran. The flume used in this study was a Straight type that had the dimensions of ۰.۴ m wide and depth and ۱۲ m long. This flume has vertical PVC sidewalls. Generally ۴۸ tests in variety slopes of ۰.۰۰۰۵ to ۰.۰۰۳ and variety discharges of ۱۰ to ۴۰ lit/s were conducted. Velocity and the shear stress were measured by using an Acoustic Doppler Velocimeter (ADV). Velocity measurements were performed with a frequency of ۲۰۰ Hz, which provided accurate statistics on the mean flow and turbulence characteristics. Detailed velocity measurements were performed in ۹ cross-sections in the Straight flume. The cross-sections were determined at: before crest, crest and after crest. Generally, in each section velocity was measured in ۱۲ point (۵, ۲۰ and ۳۵ cm from flume side and ۴ points from bed). For All tests, flow depth was kept constant. In this study generally ۴۸ test were tested under different hydraulic conditions. It was observed that the peak value of the bed shear stress appeared on the midpoint of upstream surface (before crest ripple) and the crest of the ripples had the lowest value of the bed shear stress. From the crest to trough (after crest) of the ripples, the general bed shear stress was in an increasing trend. It was generally found that with increasing Froude number and the bed shear stress increased. Also, in the case of parallel ripple bed form, the shear stress was about ۲۶% more than that of plane bed and in the case of flake ripple bed form the increasing rate was ۲۳%. It indicated that the shear stress was much affected by the parallel shape of ripple bed form compared with the flake shape, as it was ۲۷% more than the flake shape.رودخانهها، در طی زمان برای رسیدن به پایداری، شکلهای بستر متفاوتی را با رسوبگذاری یا فرسایش در بستر خود ایجاد میکنند. از راههای شناسایی رفتار رودخانهها، مطالعه و بررسی ساختار جریان و شیوهی شکلگیری شکلهای بستر در آنها است. در رودخانههای آبرفتی بخشی از تنش برشی مربوط به شکل بستر است. در این پژوهش به بررسی تنش برشی بستر، روی دو نوع شکل بسترشکنج (موازی و پولکی) پرداخته شده است. بدینمنظور آزمایشهایی در چهار شیب و چهار دبی روی شکنجهای مصنوعی ساخته شده در آزمایشگاه هیدرولیک دانشگاه شهرکرد انجام شد. برای اندازهگیری تنش و سرعت جریان از دستگاه سرعتسنج سهبعدی ADV استفاده شد. نتایج نشان داد میزان تنش در تمام آزمایشها، روند ثابتی داشته است؛ بهگونهای که روی وجه بالادست شکنج، ماکزیمم مقدار را دارد و با نزدیک شدن به تاج از مقدار آن کاسته میشود و در تاج، کمترین مقدار را دارد. همچنین نتایج نشان داد شکنجهای موازی و پولکی بهترتیب 26 و 23 درصد از میزان کل تنش برشی را تشکیل میدهند. میزان تنش برشی بستر، در روی شکنجهای موازی، 27 درصد بیشتر از مقدار تنش برشی بستر روی شکنجهای پولکی است.https://iwrj.sku.ac.ir/article_10581_73601bc3bd5a961a61a973e92e29f169.pdfدانشگاه شهرکردپژوهش آب ایران2008-123512220180622Numerical Investigation of Changes in Flow Pattern and Velocity Profiles Caused by Bed Discordance at the Entrance of Intakeبررسی عددی تغییرات الگوی جریان و پروفیل های سرعت در اثر اختلاف رقوم بستر کانال ها در آبگیرهای جانبی91710582FAسهرابکریمیحسینبنکداریJournal Article20140616Diverting flow from rivers and channels is one of the methods of transfer water for agricultural and industrial purposes. Dividing channels are also used in urban wastewater in collecting system. Intakes are amongst hydraulic structures which are used for the purposes of controlling and deviating flow in agricultural irrigation and drainage networks and also in sewer systems. In some cases, energy is produced through intakes. Determining the model of the flow, which is entering the branch channels from the main channel, is of utmost important in these hydraulic structures.<br />A part of flow in the main channel is deviated and enters the branch channel when impounding the river due to the suction force applied to it; as a result, flow separation zone and flow compression zone are formed near the entrance of the intake channel. The flow deviated into the intake has complex properties. The flow particles rotate in the separation zone, near the entrance wall of the intake channel, and the longitudinal velocity of the flow decreases and it increases in the opposite direction of the flow. The longitudinal velocity intensely increases in the compression zone, due to the density of the flow lines, and reaches its maximum levels. Therefore measuring the flow velocity in the flow separation zone and the flow compression zone is difficult and accompanied with error. Normally, flowmeters are installed in intakes in order to compute the flow discharge. A very complex flow is formed as the flow diverts from the main channel into the branch. As the flow approaches the branch channel, it undergoes lateral acceleration and is divided into two sections due to the suction pressure from the diversion. Entering the intake, the flow loses balance because of lateral pressure gradient and shear force and the centripetal force and this leads to the formation of secondary flow. A large number of experimental and numerical studies have been conducted on the flow within the intakes. Simulating the flow field, using numerical methods, reduces experimental costs and saves time therefore numerous studies have been conducted on the flow hydraulics in the diversion channels. The flow hydraulics in diversion channels have been three- dimensionally simulated in liquid and gas phases. In these studies finite volume method was widely used. Ramamurthy et al. (2007) conducted a numerical research in an intake with a 90 degree diversion and calculated the velocity of the flow within the channel through numerical calculations and compared the results with experimental data. They studied the separation zone in the intake channel and came to the conclusion that increase in dewatering ratio leads to an increase in the vortex’s strength. Mignot et al. (2012) used 3D numerical model to simulate flow patterns through junctions. In their study, in order to evaluate errors flow rate measurements were done by installing sensors in various locations, at the downstream of the junction. They showed that the measured discharge performed by sensors can produce the error more than 60% from real discharge. When fluid is flowing within a main channel with an intake, it enters the branch channel due to the suction force from the branch channel which causes lateral acceleration in the flow. When the flow enters the branch channel, separation area is formed on one side of the branch channel and flow contraction forms at the other side, due to the development of the flow. These phenomena lead to the flow having a thoroughly three- dimensional behavior.<br />The flow’s behavior has been three- dimensionally modeled in the deviation location through using ANSYS-CFX software, in this study. The results of the numerical model with a 90- degree contact angle have been compared to the experimental results, for the purposes of verification and then effects of the bed elevation difference of the meeting channels on the flow pattern structure were studied. The obtained results indicated that increase in the bed level of the main channel (0.05m higher than the branch channel bed) leads to: (1) moving high-speed lines of the flow upwards, from the bottom to the water surface; (2) disappearing of the separation area in the entrance of the branch channel; (3) increasing the intake ratio in the branch channel; (4) transferring the secondary flow from the bottom to the middle and therefore reducing of erosion intensity in the bed and floor of the branch channel.در آبگیرهای جانبی، هنگامی که سیال در کانال اصلی جریان دارد، به علت اعمال نیروی مکشی از طرف کانال جانبی شتاب عرضی ایجاد شده وارد کانال جانبی میشود. به هنگام ورود جریان به کانال جانبی، به علت گسترش جریان، ناحیه جداشدگی در یک سمت دیواره کانال انشعابی و انقباض جریان در سمت دیواره مقابل شکل میگیرد. این پدیدهها موجب میشوند جریان، رفتاری کاملاً سهبعدی داشته باشد. در این مطالعه با استفاده از نرمافزار ANSYS-CFX، رفتار جریان بهصورت سهبعدی در محل انحراف شبیهسازی شده است. برای صحتسنجی، نتایج مدل عددی آبگیر جانبی با زاویه اتصال 90 درجه با نتایج آزمایشگاهی مقایسه و سپس اثر اختلاف رقوم بستر کانالهای متلاقی بر ساختار الگوی جریان مطالعه شده است. نتایج به دست آمده نشان میدهد افزایش تراز بستر کانال اصلی نسبت به بستر کانال فرعی، موجب بالارفتن جریان از کف به سطح آب و از بین رفتن ناحیه جداشدگی نزدیک کف در کانال انشعابی میشود و کاهش قدرت جریان ثانویه و آثار فرسایش در کف کانال فرعی را باعث خواهد شد.https://iwrj.sku.ac.ir/article_10582_106fac81e07001e1825eadbb39fcde11.pdfدانشگاه شهرکردپژوهش آب ایران2008-123512220180622Calibration of Palmer drought severity index in Iranواسنجی شاخص خشکسالی پالمر در ایران192810583FAساراآزادیسعیدسلطانی کوپاییمنیرهفرامرزیسعیدپورمنافیJournal Article20140721It will be addبرای کمیسازی خشکسالی، شاخصهای مختلفی توسعه داده شدهاند که هر کدام دارای نقاط قوت و ضعفی هستند. ضریبهای برخی از معادلات این شاخصها، مربوط به شرایط مناطق استخراج آنها است که برای دستیابی به نتایج قابل اعتماد در مناطق مختلف دیگر، لازم است مورد واسنجی قرار گیرند. هدف این پژوهش واسنجی ضرایب شاخص پالمر برای ایران است. به این منظور از دادههای دما و بارش در مقیاس ماهانه در دوره آماری 2002-1990 و رطوبت ابتدایی خاک مربوط به 506 حوضه مطالعاتی کشور استفاده شد و میانگین وزنی اطلاعات برای هفده حوضه کشور به دست آمد. سپس شاخص پالمر برای کل ایران مورد واسنجی قرار گرفت و بهصورت جداگانه برای شرایط خشک و تر به ترتیب ضرایب دوگانه (0.892، 0.002) و (0.946، 0.002) در مقایسه با معادله پالمر با ضرایب (0.897، 0.333) که تنها برای شرایط خشک بود، به دست آمد. نتایج این پژوهش انطباق بسیار خوبی را در اکثر حوضهها برای سالهای 2000 و 2001 بهعنوان خشکترین سالها و سالهای 1992 و 1993 بهعنوان مرطوبترین سالهای مورد بررسی با توجه به نتایج حاصل از تحلیل شرایط بارشی سالهای مورد نظر نشان داد. نتایج این پژوهش زمینهای را برای واسنجی شاخص پالمر و ارزیابی خشکسالی در مناطق اقلیمی مختلف ایران فراهم میکند.https://iwrj.sku.ac.ir/article_10583_1b141c19b8516ff9a26065d66ecd7146.pdfدانشگاه شهرکردپژوهش آب ایران2008-123512220180622Assessment of Meteorological Drought Characteristics using the Run Theory and Markov Chain Models in Khuzestan Provinceبررسی ویژگیهای خشکسالی هواشناسی استان خوزستان با استفاده از تئوری RUN و مدل زنجیره مارکوف293910584FAبهزادعادلیعلیرضانفرزادگانآرشملکیاناحمدنوحه گرJournal Article20141103هدف از این پژوهش بررسی چرخههای خشکسالی و احتمال وقوع آنها در استان خوزستان با به کارگیری شاخص بارش استاندارد (SPI) و ترکیب تئوری RUN و مدل احتمالاتی و استوکاستیک زنجیره مارکوف میباشد. بدینمنظور ابتدا با استفاده از نمایه SPI وضعیت خشکسالی 45 ایستگاه منطقه با طول دوره آماری 31 ساله تعیین گردید. سپس با مدل زنجیره مارکوف در محیط نرمافزار متلب، ماتریس فراوانی وضعیتهای خشکسالی (خشک، نرمال و تر)، ماتریس احتمال ماندگاری و ماتریس احتمال انتقال محاسبه شد. در نهایت احتمال وقوع خشکسالی، تعداد متوسط خشکسالی قابل انتظار و مدت تداوم خشکسالیها در طول دوره شبیهسازی به دست آمد. به منظور بررسی مطابقت زنجیره مارکوف مرتبه اول بر سری زمانی هر ایستگاه از آزمون کای اسکوئر استفاده شد. نتایج آزمون کای اسکوئر نشان داد که زنجیره مارکوف مرتبه اول بر سری شاخص بارش استاندارد هر ایستگاه در سطح 95 درصد اطمینان مطابقت دارد. نتایج بیانگر احتمال وقوع برابر با 30، 35، 35 درصد به ترتیب برای دورههای خشک، نرمال و تر در سطح منطقه مورد مطالعه است. همچنین نتایج نشان داد که احتمال انتقال از وضعیت رطوبتی نرمال به وضعیت خشکسالی، بسیار بیشتر از احتمال انتقال از وضعیت ترسالی به شرایط خشکسالی است.https://iwrj.sku.ac.ir/article_10584_cf372cbe6eae54c6a6dfb3ebbcdc3404.pdfدانشگاه شهرکردپژوهش آب ایران2008-123512220180622Numerical simulation of water surface profiles on ogee and Stepped Spillway by finite volume and finite element methodsشبیه سازی عددی پروفیل سطح آب روی سرریزهای اوجی و پلکانی با روش حجم محدود و المان محدود414910585FAشبنموکیلیJournal Article20141218The spillway is one of the most important elements of dam building. So studying and designing of the spillway hydraulic should be considered in dams and other similar projects. The ogee spillway, because of its superb hydraulic characteristics, has been widely studied. Its ability to pass flow efficiently and safely, when has been properly designed, with relatively good flow measuring capabilities, has enabled engineers to use it in a wide variety of situations. In the last two decades, there has been an increasing interest in the stepped spillways in various laboratory experiments around the world. This is partly because of technical advances in the construction of Roller Compacted Concrete (RCC) dams and considerable amount of energy dissipation along the chute, leading to reduction in the size of the stilling basin. Flow analysis using laboratory experiments usually involves considerable time and cost requirements .Nowadays, availability of computational fluid dynamic (CFD) programs and powerful computers has resulted in increasing usage of numerical methods of flow analysis. Free surface flows are encountered in hydraulic engineering problems including water jets, weirs and around gates. For the numerical modelling of a steady flow, the area of calculation and therefore the position of the free surface have to be known. The main object of this study is numerical analysis of free surface profiles on ogee and stepped spillways by finite volume and finite element methods and comparison of the two methods.<br />The physical laws governing a fluid flow problem are represented by a system of partial differential equations regrouping the continuity equation, the Navier-Stokes equations and any additional conservation equations. The numerical analysis resolves these equations by accurate and complex numerical schemes. A program or code, where the numerical algorithm is implemented, is then solved on a computer. In recent study experimental results offered by Tabara and CHatila (2005) have been used to investigate stepped spillway physics models of Tabara and Chatara (2004) for studying ogee spillway. FLUENT and ADINA software have been used to simulate flow field of types of stepped and ogee spillways. It should be noted that k-£ model has been applied in order to modeling turbulence. Gambit preprocessor software is a tool for networking flow field. In recent study we have used PRESTO scheme for discretization of pressure, quick plan for discretization of terms of displacement of momentum equations, turbulence formulas and PISO algorithm for coupling velocity and pressure. In finite element method, Galerkin relation has the second order accuracy. SUPG method is used in momentum equations and turbulence for discretization of term advection which is effective in problem convergence. Meshing type has been selected as triangle form in ADINA code, but quadrilateral in FLUENT code regarding the spillway geometry. In some area structured mesh and in some other ones non-structured mesh have been chosen. Due to existence of rotatory flows over the steps, more fine meshes have been used in both codes near to body of stepped spillway as well as ogee spillway, because of the velocity gradient nearby wall, where flow enters spillway channel from reservoir. <br />In recent study, water surface profile has been simulated in four types of stepped spillways and 3 types of ogee spillways on the basis of finite element method using FLUENT code and finite volume method using ADINA code. Relatively close consistency has been observed between water surface profiles in both codes by comparing experimental results. Note that free surface profile simulated over the ogee spillway was closer to water surface profile evaluated in laboratory than the profile by finite element method. There were observed better consistency in results from free surface profile over stepped spillway with finite volume method. Maximum differences between results of water surface profile in numerical model of FLUENT and ADINA were nearly 1.2 cm and 1.6 cm, comparing with laboratory results respectively. This value in numerical simulation is acceptable regarding to different meshing in model networking. On this basis, numerical methods of FLUENT and ADINA are proper in order to simulate similar structures for saving costs due to construction of physical model. Flow surface can be determined considering the lower error of FLUENT model in measuring free surface flow; thereby, designing lateral walls of spillway is realized with more precise.هدف اصلی از این مطالعه، بررسی عددی پروفیل سطح آزاد جریان روی سرریز اوجی و پلکانی با روشهای حجم محدود و المان محدود و مقایسه این دو روش است. بدینمنظور کد Fluent بهعنوان نمایندهای از روش حجم محدود با کد ADINA بهعنوان نمایندهای از روش المان محدود با نتایج آزمایشگاهی مقایسه شده است. شایان ذکر است برای مدلسازی آشفتگی از مدل بهره گرفته شده است. با بررسی نتایج، هماهنگی خوبی بین این دو روش و نتایج آزمایشگاهی مشاهده شده، اما با توجه به نتایج آزمایشگاهی موجود، در برخی نقاط روش حجم محدود در مقایسه با روش المان محدود، نتیجه قابل قبولی را ارائه کرده است. همچنین حداکثر خطا در پروفیل سطح آب در مقایسه با نتایج آزمایشگاهی به اندازه 2 میلیمتر در نزدیکی دیواره سرریز مشاهده شده است.https://iwrj.sku.ac.ir/article_10585_a576eafbce762079f7d1f77fca1c5cc2.pdfدانشگاه شهرکردپژوهش آب ایران2008-123512220180622Estimating flow And discharge Coefficient Equations for Lopac Gate In Submerged Condition, Based on the Momentum Equationبرآورد معادلات جریان و ضریب دبی دریچه های سالونی در شرایط مستغرق، با استفاده از رابطه مومنتم515810586FAفاطمهیوسفوندمحمد جوادمنعممحمد رضاکاویانپورJournal Article20141220دریچههای سالونی، از جمله سازههای کنترل و تنظیم جریان آب در کانالها هستند. با توجه به بررسیهای هیدرولیکی اندک بر روی این سازه، جهت توسعه معادلات جریان، به ویژه در شرایط مستغرق، در این پژوهش، خصوصیات جریان عبوری از دریچههای سالونی در شرایط مستغرق با استفاده از معادله مومنتم و بهرهگیری از نتایج آزمایشگاهی بررسی شده است. در شرایط جریان مستغرق، معادلهای برای تخمین دبی دریچههای سالونی بر اساس معادله مومنتم در نظر گرفته شد. همچنین با استفاده از نتایج آزمایشگاهی و انجام رگرسیون بین پارامترهای بدون بعد مؤثر، معادلهای صریح برای ضریب دبی دریچههای سالونی در شرایط جریان مستغرق ارائه شد. نتایج نشان داد که ضریب دبی تا زاویه 52.5 درجه (نسبت بازشدگی= 0.39)، روند صعودی داشته و پس از آن کاهش مییابد. برای ارزیابی دقت معادله پیشنهادی، جذر میانگین مربعات خطا (RMSE) و میانگین خطای نسبی (MAPE) محاسبه گردید. نتایج نشان میدهد معادلات پیشنهادی برای دبی و ضریب دبی دریچههای سالونی دارای حداکثر خطایی برابر10%± است و با دقت مطلوب، تخمین مناسبی از این دو پارامتر را ارائه میدهند.https://iwrj.sku.ac.ir/article_10586_8b77b4b5156dc11dec152c6c71481565.pdfدانشگاه شهرکردپژوهش آب ایران2008-123512220180622Application of a multi-satellite data fusion-disaggregation algorithm to obtain daily cloud-free snow cover and snow water equivalent maps (Case study: Karun watershed, Ahwaz, Iran)بهکارگیری یک الگوریتم ادغام-ریزمقیاسسازی دادههای چندماهوارهای بهمنظور تولید نقشههای روزانه ابرآزاد سطح برف و آب معادل برف (مطالعه موردی: حوضه کارون)596910587FAفرزینپرچمی عراقیفاطمهسمیعپورJournal Article20160314Snow cover, as an important component of land cover, is one of the most active natural and plays an important role in hydrological processes and climate. Variability in snow covered area has a significant influence on water and energy cycles, as well as socioeconomic and environmental repercussions. Frequent and long-term snow observation, accurate snow cover (SC) mapping and snow water equivalent (SWE) estimation are crucial for operational flood control, water delay planning, and resource management in snowmelt-dominated basins. Today, satellite-derived snow products obtained from visible and infrared imagery, as well as passive microwaves are available on the Internet, with few recently availability in near-real time . Optical sensors (e.g., Landsat, Advanced Very High Resolution Radiometer-AVHRR, Moderate Resolution Imaging Spectroradiometer-MODIS, Systeme Probatoire d’Observation de la Tarre-SPOT) have been well developed to provide snow information with good temporal and/or spatial resolution. But, cloud cover is a major factor in optical remote sensing that limits our capability to map the Earth’s surface. It is often not an easy task to collect a time-series cloud-free images for a particular area of interest, using optical remote sensing, which limits their wider applications for SC monitoring. Space-borne passive-microwave radiometers (e.g., Scanning Multichannel Microwave Radiometer-SMMR, Special Sensor Microwave/Imager-SSM/I, Advanced Microwave Scanning Radiometer-Earth Observing System-AMSR-E), can penetrate cloud to detect microwave energy emitted by snow and ice and provide information on SC and SWE. These passive microwave data are well suited to snow cover monitoring because of the characteristics such as all-weather imaging, large swath width with frequent overpass times. But, the coarse spatial resolution (e.g., ۲۵ km of AMSR-E daily SWE product) hinders their applications in operational hydrological modeling. It seems that the combination of MODIS and AMSR-E can take advantage of both high spatial resolution of optical data and cloud transparency of passive microwave data. In this study, daily cloud-free SC and SWE maps at the ۵۰۰-m resolution were produced for Karun watershed, Ahwaz, Iran (January ۲۵–۳۲, ۲۰۰۴). The daily MODIS-Terra, MODIS-Aqua, and AMSR-E snow data products were used via a fusion-disaggregation algorithm. The developed SC and SWE maps were evaluated, using total accuracy of snow mapping in clear-sky (Os) and all-sky (Oa) conditions, underestimation (UEc) and Overestimation (OEc) of snow covered area in clear-sky condition, snow accuracy in clear-sky (Sc) or in all-sky (Sa) conditions, and no snow accuracy in clear-sky (NSc) or in all-sky (NSa) conditions. The results of this study showed that the combination of MODIS-Terra and MODIS-Aqua considerably reduced the cloud coverage in such high resolution optical data. Although MAC-SC and MAC-SWE products have been developed to have ۵۰۰ m spatial resolution, the massive and continuous cloud cover (larger than ۲۵ km in size) in the MODIS-Terra and MODIS-Aqua and, hence, TAC products were simply replaced by the coarse AMSR-E pixels. In this case, although those cloud coverages were removed in the MAC-SC and MAC-SWE products, the actual resolution of the snow or no-snow pixels kept ۲۵ km and such pixels had the false spatial resolution of ۵۰۰ m. The SWE redistribution of AMSR-E based on MAC-SC products enhanced (to some extent) the spatial resolution of the AMSR-E SWE products. However, there was no measured data to evaluate the accuracy of the enhanced SWE products. It can be concluded that for pixels with scattered cloud cover (less than ۲۵ km in size) in the TAC products, the MAC-SC and MAC-SWE products indeed improve the spatial resolution of those pixels to ۵۰۰ m, while for massive cloud cover (larger than ۲۵ km in size), the actual resolution of those pixels in the MAC-SC and MAC-SWE products are ۲۵ km, even in ۵۰۰ m pixel size. Despite of these limitations, the MAC-SC and MAC-SWE maps are suitable for hydrological, meteorological modeling on a daily basis in the study area.در پژوهش حاضر، امکان تولید نقشههای ابرآزاد روزانه و هشت روزه سطح برف (SC) و عمق آب معادل برف (SWE) با تفکیک مکانی 500 متر از طریق یک الگوریتم ادغام-ریزمقیاسسازی که مبتنی بر ترکیب مزیت تفکیک مکانی مطلوب تصاویر حاصل از سنجندههای نوری MODIS نصب شده بر روی ماهوارههای Terra و Aqua (بهترتیب، MODIS‑Terra و MODIS‑Aqua) با مزیت پشتنمایی پوشش ابر سنجنده میکروویو AMSR‑E میباشد، مورد بررسی قرار گرفت. این الگوریتم برای حوضه کارون، سال آبی 1383-1382، بهکار گرفته شد. ادغام نقشههای SC حاصل از سنجندههای MODIS‑Terra و MODIS‑Aqua (TAC) موجب شد میانگین سهم پیکسلهای ابری در نقشه TAC طی دوره مطالعاتی در مقایسه با نقشههای MODIS‑Terra و MODIS‑Aqua بهترتیب، بهمیزان 17.29 و 14.43 درصد کاهش یابد. متوسط دقت کلی نقشههای SC در شرایط آسمان صاف (مقایسه بهازای پیکسلهای غیرابری) برای تصاویر حاصل از سنجندههای MODIS‑Terra و MODIS‑Aqua بهترتیب، برابر با 97.20 و 95.86 درصد بود. متوسط دقت کلی نقشههای SC در شرایط جوی عام (مقایسه بهازای پیکسلهای ابری و غیرابری)، شامل نقشههای MODIS‑Terra، MODIS‑Aqua، TAC و MAC‑SC (حاصل از ترکیب نقشه TAC و AMSR‑E) بهترتیب، برابر با 49.38، 51.47، 65.48 و 90.15 درصد بود.https://iwrj.sku.ac.ir/article_10587_244c14ea3d510ea640df31ff78b3158a.pdfدانشگاه شهرکردپژوهش آب ایران2008-123512220180622Rules governing groundwater (wells) resources in Iranمقررات حاکم بر منابع آبهای زیرزمینی(چاه ها) در ایران718010588FAسیدناصرالدینبدیسارمحمدصادقاحمدیJournal Article20160629Shortage of water resources and successive droughts are one of the most important types of problems caused by climate changes and governmental activities that will undoubtedly cause great disputes in the future. Global water crisis, drought and famine and their effects have made governments to make their utmost effort to control and use groundwater resources. Groundwater, as one of the main and most important water resources in Iran, is a major supplier of drinking, agricultural, and industrial water and has an important role in economic growth. Historical changes of water laws from ۱۹۲۸ so far, not only have not been in conformity with modern circumstances, but also have increased violations and reduced power and authority of sovereignty over the water. The process began and strengthened with the law of equitable distribution of water and subsequent laws. The laws has led to a situation that despite the legal decisions, a large number of illegal wells was made during the period of ۱۹۹۴ to ۲۰۰۵. There are still more than ۲۵۰ thousand illegal wells in the current situation (Mazaheri and Abdulmanafi, ۲۰۱۵) and there is an incentive to continue these activities and increasing violations. In spite of the weaknesses in the legislation, the capacity and powers of the existing laws are not used properly and a remarkable part of the intentions of the legislator is not met. In the law of equitable distribution of water, no new decree has been issued regarding to the private ownership of water resources, except groundwater. Whether beneath a private land or public land, water is absolutely a joint asset that people can own by obtaining permission from the government. In fact, what has changed with the adoption of new rules is the issue of water resource allocationand private ownership of water resources still remains. However, the assumption of ownership of the water in the law of equitable distribution of water does not mean absolute ownership of holders. Since the fluid nature of groundwater prevents the physical possession of the underground source by the holder, it can be said that traditional rules of use of groundwater do not generally provide any right of ownership that the holder can appeal to the legal system. Based on the studies of ministry of energy, different regions of the country have been divided into two forbidden and free zones in terms of the possibility of exploiting underground water. In free zones, individuals can submit a written request to the regional water companies in each province to get a license for digging wells or constructing subterranean and exploiting underground water resources for any purposes. The use of groundwater resources up to ۲۵ cubic meters per day for domestic, drinking, sanitation, and watering use does not need a permit in these areas and people can only use up to the abovementioned figure by informing the Ministry of Energy. In the forbidden zone, licensing well digging for industrial and civil projects of government with the approval of the Ministry of Energy and drinking water supply for cities, towns and villages with the offer of relevant ministries or their affiliated organizations. Industrial and drinking water, livestock and poultry health water supply with the certificate issued by the competent authorities will be possible based on the water facilities and the approval of the Ministry of Energy. Obvious point about the law is that tens of thousands of different beneficiaries didn’t see it necessary to make use of law for getting legal license. Because offenders, within three decades of experience, have found that regulated well digging leads to government’s supervision over their destiny and endless harassment upon them. This is the process that began and strengthened with the equitable distribution of water and subsequent laws. One of the opportunities created in forbidden areas for well digging licensing is related to livestock and greenhouse units. Experience has proven that these licenses are solely a certificate to permit legal well digging and investigations show an overdraft of more than ۶۰ to ۷۰ percent of these units. It can be asserted that more than ۶۰% of these units have virtually no greenhouse or livestock activities and just tremendously extract water and continue traditional agriculture and high-consuming activities (in term of water). In many cases, the owners have used the value added of converting rain-fed land around wells to water-fed lands and try to sell with high prices.کمبود منابع آبی و خشکسالیهای پیدرپی، از مهمترین مشکلات ناشی از تغییرات اقلیمی و فعالیتهای دولتها است که بدون شک در آینده موجب اختلافات بسیار زیادی خواهند شد. بحران آب در سطح جهانی و تلاش دولتها برای مبارزه با خشکسالی و قحطی و آثار ناشی از آن، دولتها را بر آن داشته است تا نهایت تلاش خود را برای کنترل و استفاده از منابع آبهای زیرزمینی به کار گیرند. آبهای زیرزمینی بهعنوان یکی از اصلیترین و مهمترین منابع آبی در سطح کشور، تأمینکنندة عمدة آب شرب، کشاورزی، صنعت و غیره است و نقش مهمی در شکوفایی اقتصاد کشور داشته و دارد. سیر تاریخی تغییرات قوانین آب از سال 1307 تاکنون، نه تنها متناسب با شرایط روز نبوده، بلکه موجب افزایش تخلفات و کاهش قدرت و اقتدار حاکمیت بر آب نیز شده است. روندی که با قانون توزیع عادلانه آب و قوانین بعدی شروع و تقویت شده است، موجب گردیده که علیرغم تعیین تکلیف تعداد زیادی از چاههای غیرمجاز طی سالهای 1373 تا 1384، هنوز در شرایط کنونی بیش از 250 هزار حلقه چاه غیرمجاز موجود بوده و انگیزه برای تداوم این اقدام و افزایش تخلفات، وجود داشته باشد. علیرغم وجود ضعفهایی در قانونگذاری، از ظرفیت و اختیارات قوانین موجود نیز به خوبی استفاده و قسمت قابل توجهی از اهداف و مقاصد قانونگذار تأمین نشده است. این مقاله با هدف بررسی مقررات حاکم منابع آبهای زیرزمینی (چاهها) و به روش توصیفی- تحلیلی به رشته تحریر در آمده است.https://iwrj.sku.ac.ir/article_10588_5d9e4a04afb9f3608ccc76c1ffa7573e.pdfدانشگاه شهرکردپژوهش آب ایران2008-123512220180622Comparison Genetic Programming model and M5 model tree in Drought Forecastingمقایسة مدلهای برنامهریزی ژنتیکی و مدل درختی M5 در پیشبینی خشکسالی819010590FAمهدیکماسیسودهقبادی خسرومحمدرضاهاشمیJournal Article20160629Drought is a temporary and recurring meteorological event, originating from a lack of precipitation over an extended period of time. The success of drought preparedness and mitigation depends on timely information about drought onset and forecasting. This information may be obtained through continuous drought monitoring, which is normally performed using drought indices. Drought is an unpleasant, naturally occurring event caused by climate change that directly affects societies through changing their access to water resources. Among the numerous indices for drought intensity rating, the EDI and SPI have widespread applications. The SPI was computed by fitting a probability density function to the frequency distribution of the monthly precipitation records of each station. A drought event is considered to occur at a time when the value of the SPI is continuously negative and ends when the SPI becomes positive. The computation of the SPI drought index for any location is based on the long-term precipitation record (at least ۳۰ years) cumulated over a selected time scale. This long-term precipitation time series is then fitted to a gamma distribution, which is then transformed through an equal probability transformation into a normal distribution. Positive and negative SPI values respectively indicate wet conditions (greater than median precipitation), and dry (lower than median precipitation). In most cases, the probability distribution that best models observational precipitation data is the Gamma distribution. Unlike most other drought indices, the EDI in its original form is calculated with the daily. The resulting EDI value represents standardized value for currently utilizable water resources, considering the continued dry period. If a negative DEP continues for more than ۱day, the addition period of EDI will increase as long as the continued days. This variable addition period is limitless. The nature of genetic programming allows the user to gain additional information on how the system performs, i.e., gives insight into the relationship between input and output data. The GP is similar to genetic algorithm (GA) but unlike the latter, its solution is a computer program or an equation as against a set of numbers in the genetic algorithm. So, GP is more attractive than traditional GA for problems that require the construction of explicit models. The GP thus transforms one population of individuals into another one, in an iterative manner by applying operators. In evolutionary computation, it can distinguish between three different types of operators which are named crossover, reproduction, and mutation. M۵ model tree approach is based on the principle of information theory that makes it possible to split the multi-dimensional parameter space and generate the models automatically according to the overall quality criterion. It allows for variation in the number of models created. The splitting in the M۵ modal tree approach follows the idea of decision tree, but instead of the class labels, it has linear regression functions at the leaves, which can predict continuous numerical attributes. Model trees generalize the concepts of regression trees, which have constant values at their leaves. Therefore, they are analogous to piece-wise linear functions (and hence nonlinear). Computational requirements for model trees grow rapidly with increase in the dimensionality of the data set. Model trees learn efficiently and can tackle tasks with very high dimensionality. The major advantage of model trees over regression trees is that model trees are much smaller than regression trees and regression functions do not normally involve many variables. This research used precipitation data on two basins in Hamedan and Lorestan Provinces to calculate the SPI and EDI indices for monitoring drought. The genetic programming model and M۵ model trees were used to predict the occurrence of drought in these two basins. It was found these models had good capability in predicting drought and enjoyed high accuracy in solving prediction problems. Another advantage of these models is that they use simple equations for predicting the phenomena under study. In the best-case scenario, the coefficients of determination for the EDI index in the M۵ model trees and in the genetic programming model were ۰.۹۷ and ۰.۹۵, respectively. Moreover, the coefficients of determination for the SPI index in the M۵ model trees and in the genetic programming model, in the best-case scenario, were ۰.۹۳ and ۰.۸۳, respectively. This suggests the M۵ model trees are more accurate compared to the genetic programming model and enjoy relative superiority because they are simpler and more understandable than the genetic programming model.خشکسالی، بهعنوان یک حادثة ناگوار طبیعی، بهطور مستقیم جوامع را از طریق تغییرات در دسترسی به منابع آب تحت تأثیر قرار میدهد. برای درجهبندی شدت خشکسالی، شاخصهای متعددی وجود دارد که از میان آنها، شاخص خشکسالی مؤثر (EDI) و شاخص بارش استاندارد (SPI) کاربرد فراوانی دارند. در این پژوهش، برای پیشبینی خشکسالی از دادههای بارش دو حوضة واقع در استانهای همدان و لرستان برای محاسبة شاخص SPIو شاخص EDI بهره گرفته و برای پیشبینی پدیدة خشکسالی از دو مدل برنامهریزی ژنتیکی و مدل درختی M5 استفاده شد. بررسیهای انجام گرفته نشان داد که این مدلها توانایی خوبی در پیشبینی پدیدة خشکسالی داشتند و از دقت مناسبی برای مسائل پیشبینی برخوردار هستند. از دیگر مزیت این مدلها، ارائة فرمولهای ساده و صریح برای پیشبینی پدیدة موردنظر است. ضریب تبیین در مدل M5 برای شاخص EDI در بهترین حالت 0.97 و در مدل برنامهریزی ژنتیکی 0.95 به دست آمد. همچنین ضریب تبیین برای شاخص SPI در بهترین حالت در مدل M5، 0.93 و در مدل برنامهریزی ژنتیکی 0.83 حاصل شد. این مهم نشاندهندة این نکته است که مدل درختی M5 در مقایسه با مدل برنامهریزی ژنتیکی از دقت بالاتری برخوردار بوده و بهدلیل سادگی و قابل فهم بودن نسبت به مدل برنامهریزی ژنتیکی دارای برتری نسبی است.https://iwrj.sku.ac.ir/article_10590_236522d75c8164f90a85448456e1d1aa.pdfدانشگاه شهرکردپژوهش آب ایران2008-123512220180622Groundwater Level Prediction Using Dynamic Bayesian Networks Based on Sensitivity Analysis (Case Study: Birjand Plain)پیشبینی سطح آبزیرزمینی با استفاده از مدل شبکههای بیزین پویا مبتنی بر تحلیل حساسیت (مطالعه موردی: دشت بیرجند)9110010589FAابراهیمابراهیمیعباسروزبهانیمحمد ابراهیمبنی حبیبJournal Article20160717The aquifers are about four percent of the water on the earth, but they are considered as the best and most accessible source of fresh water. In recent years, they have been faced with severe water withdrawal, therefore some plains was considered as forbidden plains that it means the water withdrawal from these aquifers is unauthorized. At some point, plains have been faced with land subsidence that showed the severity of the disaster. Given such a critical situation in aquifers, management of groundwater resources in the form of tools such as monitoring the level of the aquifers is essential. One of the plains in Iran that has a critical groundwater resource is Birjand plain which requires management measures to be protected from future water resources crisis. Prediction of groundwater level in future periods is a useful tool to enforce management measures before a crisis occurs. Thus, in this study, groundwater level was predicted in Birjand aquifer taking ۱۰ monthly forecasting scenarios in a period of ۵ years and in both crisp (continues) and clustering approaches using probabilistic Dynamic Bayesian Networks (DBNs). Nowadays, various tools are used to predict the aquifer level including mathematical models, artificial neural network, neuro-fuzzy, Bayesian networks, and time series and so on. In recent years, due to the flexible and simple structure, Bayesian networks have been used for predictions of different parameters, especially in forecasting of hydrological parameters. Bayesian network as a modern forecasting probabilistic method shows probabilistic relationships between a set of variables by graphical model. It represents the dependence structure among several factors, that affecting on each other, and is based on Bayesian theory. Dynamic Bayesian Networks have been extended from Bayesian Networks which are created for two purposes: first, as the cycle of dependency detector over the time, quite similar to Markov model; second, as the fixed process which is repeated in fixed-time interval. Another feature of Dynamic Bayesian network is their willingness to approximately structured changing. In this study, the input data (predictor parameters) of the model includes: temperature, rain, evaporation, monthly aquifer recharge in each Thiessen Polygon (Recharge), monthly withdrawals of groundwater in each aquifer Thiessen Polygon (discharge), groundwater levels in the current month and the groundwater level in the next month (predicted parameter). The first step in modeling by the dynamic Bayesian network is determining the dependent and independent data for calibration and validation. Model calibration data in both crisp and clustering approach include a ۱۲-year period (۱۹۹۸ to ۲۰۰۹) and data validation include ۵-year period (۲۰۱۰ to ۲۰۱۴), in monthly time step. Depending on the type of input data, both crisp and clustering approach was used. In the crisp approach, the probability functions were used and the predicted data were obtained by using the training data. In the clustering approach, by assigning each of the numbers to the right cluster, the modeling was done. A cluster is collection of objects that their relative distance to each other is low and relative to other members is high. In the first approach by using crisp data and NPC training structure in confidence level of ۵%, the training was applied. In the second approach, the Silhouette index was calculated by using MATLAB software and by using the validation Silhouette index, and then, the number of clusters was determined. Finally, the clustering was performed by using k average method. Then, training was done in the second approach, using clustered data and NPC training structure in confidence level of ۵%. Considering ۱۰ different scenarios to predict groundwater level in the next month, the uncertainty of predicted parameters in both crisp and clustering approach were assessed. In fact, using these scenarios, sensitivity analysis was performed to check the accuracy of the model with respect to the existence or absence of different predictor parameters. In addition, the uncertainty of the model output is evaluated using dynamic Bayesian network probabilistic analysis. The results of the selected scenario in crisp approach showed the high prediction accuracy of Bayesian networks. For example, in piezometers ۴ and ۹, the coefficient of determination was estimated about ۰.۹۸. According to the results, crisp dynamic Bayesian networks approach predicted hydrograph aquifer more accurate than clustering approach. Due to the low efficiency of clustering approach in predicting groundwater hydrograph, to obtain the accuracy of ۱۰ scenarios predictions in this approach, instead of coefficient of determination (R^۲) and root-mean-square error (RMSE), the percentage of correct predicted clusters was determined. According to the results, the clustering approach predicts clusters with high accuracy for different piezometers. The scenario ۶ had the best prediction which all predictor parameters except evaporation were used for the prediction. In this scenario, R^۲ and RMSE were showed good accuracy as ۰.۹۹۴۶ and ۰.۱۲۷۵, respectively. The other scenarios had also the accuracy in their predictions very close to scenario ۶, except scenario ۹ which the groundwater levels were not used as input. Thus, in the crisp approach, the groundwater levels have a substantial impact on the accuracy of the prediction. Generally, in crisp approach, all predictor scenarios have acceptable accuracy of over than ۹۰% except scenario ۹. In clustering approach, by examining the accuracy of the scenarios in predicting clusters, most scenarios were accurate except scenario ۹. Dynamic Bayesian Network model in clustering approach correctly predicted clusters but, unlike the crisp approach in predicting hydrograph, it was not able to present acceptable results. The results showed the ability of the proposed model in planning and management of groundwater resources, reducing the risk of aquifer level declining by applying short term management scenarios and predict its effects on rehabilitation. Moreover, this model can be used in the similar plains for aquifer management.پیشبینی سطح آب زیرزمینی، نقش مهمی در مدیریت منابع آب زیرزمینی دارد. در این پژوهش، با استفاده از شبکههای بیزین پویای احتمالاتی و در نظر گرفتن 10 رویکرد پیشبینی ماهانه، با استفاده از دادههای واسنجی 12 سال آبی، سطح ایستابی آبخوان بیرجند، در یک دورة آبی 5 ساله و در دو رویکرد صریح (پیوسته) و خوشهبندی (دستهبندی) صحتسنجی و پیشبینی شد. در رویکرد پیشبینی صریح، از دادههای صریح ماهانه استفاده و در رویکرد خوشهبندی با استفاده از شاخص عرض سیلهوت تعداد خوشههای بهینه تعیین و با خوشهبندی دادهها، از دادههای خوشهبندی شده برای آموزش مدل بیزین استفاده و پیشبینی مدل با استفاده از دادههای خوشهبندی انجام شد. با اعمال واسنجی در مدل بیزین و بررسی نتایج سناریوهای تحلیل حساسیت مختلف، کارایی بالای شبکههای بیزین پویا بهویژه در رویکرد صریح، مشاهده شد. با بررسی 10 رویکرد تحلیل حساسیت اعمال شده برای پیشبینی سطح ایستابی آبخوان، مشاهده شد که از بین عوامل پیشبینی کننده، پارامتر سطح آب زیرزمینی در ماه فعلی اثرگذاری بالایی را در افزایش دقت مدل برای پیشبینی سطح ایستابی آبخوان ماه بعدی دارد؛ به گونهای که با حذف این پارامتر در مدل بیزین، ضریب تبیین از 0.9925 به 0.0004 کاهش یافت و میانگین مجذور مربعات خطا نیز از 0.2654 به 0.9709 متر افزایش یافت. همچنین بالاترین ضریب تبیین در بین سناریوهای پیشبینی 0.995 است.https://iwrj.sku.ac.ir/article_10589_f74e95cf0ef6ccd85c791b5d351aa327.pdfدانشگاه شهرکردپژوهش آب ایران2008-123512220180622Investigation of Shannon Entropy Theory in Weighting of Water Quality Index (Case Study: Mighan Aquifer)بررسی تئوری آنتروپی شانون در وزندار کردن شاخص کیفیت آب (مطالعه موردی: دشت میقان)10111010591FAامیرحسینپارسامهرحسینملکی نژادزهراخسروانیJournal Article20160814اهمیت منابع آب زیرزمینی، بهعنوان یکی از مناسبترین گزینههای تأمین آب شرب، بر هیچکس پوشیده نیست. در این پژوهش، برای بررسی کیفیت آب زیرزمینی دشت میقان از نظر شرب، از استاندارد سازمان بهداشت جهانی و روش شاخص کیفیت آب، استفاده شد. برای این منظور، دادههای 40 نمونة آب زیرزمینی، از نظر 11 پارامتر شیمیایی بررسی شدند. برای جلوگیری از قضاوتهای کارشناسی در تعیین وزن هر یک از پارامترها، از تئوری آنتروپی شانون استفاده شد. در ادامه پس از تحلیل عاملی دادهها، طبقهبندی کیفی نمونهها، بر اساس آنتروپی وزندار شاخص کیفیت آب انجام شد. نتایج تحلیل عاملی نشان داد که 70 درصد واریانس تغییرات کیفی آب زیرزمینی منطقة مورد مطالعه، با استفاده از 5 عامل تحلیل میشود: عامل اول 21.91 درصد، عامل دوم 13.9 درصد، عامل سوم 13 درصد، عامل چهارم 10.9 درصد و عامل پنجم 10.7 درصد تغییرات واریانس را توجیه میکنند. بیشترین و کمترین وزن پارامترها بر اساس تئوری آنتروپی شانون مربوط به Cu و pH با وزن 34.82 و 0.02 درصد بود. طبقهبندی نمونههای مورد مطالعه بر اساس آنتروپی وزندار شاخص کیفیت آب حاکی از این است که 57.5 درصد از نمونهها دارای کیفیت بسیار خوب، 27.5 درصد نمونهها دارای کیفیت خوب، 12.5 درصد نمونهها دارای کیفیت متوسط و 2.5 درصد آنها دارای کیفیت بد بود.https://iwrj.sku.ac.ir/article_10591_dd4729902a3476b2bc9675e3530a852c.pdfدانشگاه شهرکردپژوهش آب ایران2008-123512220180622Flood frequency analysis using power law approach (Case study: Dez Basin)تحلیل فراوانی سیلاب با استفاده از رویکرد قانون توانی (مطالعه موردی: حوضه آبریز دز)11112010592FAفرشاداحمدیفریدونرادمنش0000-0001-5401-2339غلامعلیپرهامرسولمیرعباسی نجف آبادی0000-0002-9897-0042Journal Article20160817Estimation of flood discharge and return period of extreme events is one of the most important factors in design of hydraulic structures. Therefore, conducting researches for improving the accuracy of estimation methods is very important. Nowadays, the fractal behavior of all earth science phenomena, including precipitation and runoff has been accepted. This method is used for modeling of natural phenomena because of its strong physical background. As power law is derived from fractal theory, it can be a suitable method for estimation of design flood. In the annual maxima method, a maximum value is extracted among all the recorded discharge occurred during a year. Therefore, in this method, out of a number of extreme events happened at the end of the year, only one value is chosen and other values are eliminated. The positive point of this method is that the extracted data are independent of each other. However, this method has its own limitations. For example, in years with high flood occurrences, the values that stand in the second and third places in terms of magnitude lose the chance to participate in the annual maxima series. On the other hand, in dry years, the occurred maximum values are far lower than the second or third ranked discharge of wet years. Thus, correspondence of the annual maximum time series with reality is not suitable, and such a selection may result in neglecting the real pattern in the recorded values. In another method, partial time series (the time series greater than a given threshold) is employed. In this sampling method, a certain threshold of flow rate is considered and all flow rates that are above the threshold, are taken into consideration. In this study, power law has been employed to select the flood partial series. Therefore, the main objective of this study is to use power law in a) selection of partial series of flood in Dez Basin, and b) flood frequency analysis. In this study, flood frequency analysis of Dez watershed during the period of ۱۹۵۶- ۲۰۱۲ was performed using two approaches of power law (PL) and ordinary statistical distributions. At first, the partial-duration flood series were extracted using power law with the intervals of ۷, ۱۴, ۳۰, and ۶۰ days, and then compared with the annual maxima series. The results indicated that the annual maxima series were not suitable for frequency analysis of the flood in Dez Basin, and the ۳۰-day partial duration series obtained from the power law has a better correspondence with the flow and properties of the Dez Basin. Examining of the independence and stationarity of the ۳۰-d partial duration series by Wald-Wolfowitz (W-W) test, confirmed the independence of the considered series. In the next step, the power distribution and ordinary statistical distributions were fitted onto the flood data of the Dez Basin, and performance of each distribution was investigated using Normalized Root Mean Square Error (NRMSE) and Nash-Sutcliffe (NS) criteria. The results showed that in the Tange Panj Bakhtiari station (TPB), power distribution had a better performance than other considered distributions, and in the Tange Panj Sezar (TPS) and Tale Zang (TZ) stations the power distribution stood in the second rank in terms of the best distribution with a slight difference. The results indicated that the annual maxima within shorter return periods estimate lower values for the flood of the studied stations. However, the partial series extracted using power law solved the problem in the annual maxima, and are in full correspondence with the physics of Dez Basin. Following selection of suitable statistical distributions, flood quintiles were calculated for return periods of ۲, ۵, ۱۰, ۲۰, ۵۰, and ۱۰۰ years in each station. Based on the calculated quintiles, it was observed that TPB station is more vulnerable to the flood occurrence, where the amount of flood increases in it with the prolongation of return period. In other words, in basins culminating in TPB station, development of warning systems and implementation of flood control programs are more needed. Since the performance of power distribution in estimating the flood in Dez Basin has been very satisfactory and calculation of its parameters and its application is easier than ordinary probability distributions, it can be suggested as the superior distribution for flood frequency analysis in Dez Basin.در مطالعة حاضر، تحلیل فراوانی سیلاب حوضة آبریز دز در دورة آماری 91-1335 با استفاده از رویکردهای قانون توانی (PL) و توزیعهای متداول آماری انجام شد. ابتدا سریهای جزیی سیلاب با استفاده از قانون توانی با فواصل زمانی 7، 14، 30 و 60 روزه استخراج و با سری حداکثر سالانه مقایسه شد. نتایج نشان داد که سری حداکثر سالانه، برای تحلیل فراوانی سیلاب حوضة آبریز دز مناسب نیست و سری جزیی 30 روزه حاصل از قانون توانی، مطابقت بهتری با وضعیت جریان این حوضه دارد. استقلال و ایستایی سری جزیی سیلاب 30 روزه با استفاده از آزمون والد- ولفوویتز (W-W) بررسی و استقلال سری موردنظر تأیید شد. در مرحلة بعد، توزیع توانی و توزیعهای متداول آماری بر دادههای سیلاب حوضة آبریز دز برازش داده و عملکرد هر توزیع با استفاده از آمارههای جذر میانگین مربعات نرمال شده (NRMSE) و معیار نش- ساتکلیف (NS) بررسی شد. مقدار آمارههای NS و NRMSE برای توزیع توانی در ایستگاه تنگ پنج بختیاری بهترتیب برابر با 0.99 و 2.75 محاسبه شد که نسبت به سایر توزیعها از عملکرد بسیار بهتری برخوردار بوده و در ایستگاههای تنگ پنج سزار (0.96=NS و 5.12=NRMSE) و تله زنگ (0.98=NS و 3.40=NRMSE) نیز با اختلاف بسیار اندکی در رتبة دوم بهترین توزیع قرار گرفت. با توجه به اینکه عملکرد توزیع توانی در برآورد سیلاب حوضة آبریز دز بسیار مناسب و محاسبة ضرایب و کاربرد آن نسبت به توزیعهای احتمالاتی آسان است، میتواند بهعنوان توزیع برتر حوضة آبریز دز پیشنهاد شود.https://iwrj.sku.ac.ir/article_10592_f6c2a0c4b566bc99d596e58638e342b0.pdfدانشگاه شهرکردپژوهش آب ایران2008-123512220180622The effects of the application of three superabsorbents (A200 Perlites and Zeolite) on soil erosion and sediments of saturated soilsتأثیر استفاده ازسوپرجاذب های پرلیت، زئولیت و A200 بر فرسایش سطحی و و رسوب زایی خاک اشباع12112910593FAرضاقضاویابراهیمامیدوارفرزانهفداییJournal Article20170226در این پژوهش، تأثیر سه نوع سوپرجاذب شامل پرلیت، زئولیت و A200 در چهار سطح صفر، 5، 10 و 15 درصد حجمی، در دو شیب 5 و 10 درصد و با 3 تکرار روی فرسایش سطحی خاک اشباع بررسی شد. این مطالعه در پلاتهای آزمایشگاهی با ابعاد 40×100 سانتیمتر انجام شد. نمونههای خاک پس از اضافهشدن سوپرجاذبها در معرض آبیاری با شدت یکسان قرار گرفتند و بعد از اشباع شدن با افزودن دبی با شدت 2 لیتر در دقیقه در مدت 20 دقیقه به پلاتها شیب 5 و 10 درصد داده و رسوب خارج شده از انتهای پلاتها جمعآوری شد. نتایج نشان داد که در هر دو شیب زمانی که سوپرجاذبها در سطحهای 5 و 10 درصد به خاک اضافه میشود، میزان رسوب خروجی از پلاتها نسبت به تیمار شاهد کاهش معنیداری داشت (P<0.05)؛ ولی زمانی که مقادیر این نوع سوپرجاذب از 15 درصد رسید در میزان رسوب اندازهگیری شده افزایش نسبی مشاهده شد. همچنین سایر نتایج در مورد اثربخشی سوپرجاذبها در کاهش رسوبدهی، نشان داد که سوپر جاذب A200 با میزان 43.6 درصد کاهش رسوب نسبت به تیمار شاهد، بیشترین اثربخشی را داشته و سوپرجاذبهای پرلیت و زئولیت نیز بهترتیب 31.3 و 16.5 درصد رسوبدهی پلات را کاهش دادهاند.https://iwrj.sku.ac.ir/article_10593_d530d454337fb09964237fecb4bea6ce.pdf