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پژوهش های ژئومورفولوژی کمی - سال ششم شماره 2 (پیاپی 22، پاییز 1396)

فصلنامه پژوهش های ژئومورفولوژی کمی
سال ششم شماره 2 (پیاپی 22، پاییز 1396)

  • تاریخ انتشار: 1396/10/02
  • تعداد عناوین: 10
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  • محمدحسین رضایی مقدم، محمدرضا نیکجو، مهدی یاسی، مسعود رحیمی صفحات 1-14
    در این پژوهش بخشی از مجرای رودخانه قره سو با استفاده از مدل ژئومورفولوژیکی رزگن مورد تحلیل و طبقه بندی قرار گرفت. این پژوهش متکی بر نقشه های توپوگرافی 1:2000 و مطالعات میدانی بوده است. در این تحقیق، برای محاسبه پارامترهای نسبت گود شدگی و نسبت عرض به عمق لب پری از مدل هیدرودینامیکی HEC-RAS به همراه الحاقی HEC-GeoRAS استفاده گردید. بررسی نتایج مدل رزگن نشان داد که اکثر مقاطع رودخانه قره سو در طبقه ی C و E مدل سلسله مراتبی رزگن قرارگرفته اند. رودخانه قره سو در طبقه C دارای مجرای پهن تر و کم عمق تری می باشد و همچنین پهنه سیلابی رودخانه در این طبقه توسعه یافته و دره های آن عریض است. این رودخانه در طبقه E نیز دارای مجرای عمیق و باریک (نسبت عرض به عمق کم) بوده ولی پهنه سیلابی آن عریض و توسعه یافته است. با در نظر گرفتن متغیر شیب و مواد بستر می توان گفت رودخانه قره سو، در بازه اول در طبقه ی C3b وE3b، در بازه دوم، سوم، چهارم و پنجم در طبقه ی C4b، E4b، C5، در بازه ششم در طبقه ی E5 و C5 و درنهایت در بازه هفتم در طبقه ی C5c و E5 قرارگرفته است. همچنین با توجه به نتایج به دست آمده می توان بیان کرد که رودخانه قره سو در بخش هایی که مقاطع در طبقه ی C قرارگرفته است، دارای حساسیت به آشفتگی بسیار بالا، پتانسیل بازیابی خوب، تامین رسوب بالا، کنترل پوشش گیاهی بسیار بالا و در بخش هایی که مقاطع در طبقه E واقع شده است، رودخانه دارای حساسیت به آشفتگی بسیار بالا، پتانسیل بازیابی خوب، تامین رسوب متوسط، و کنترل پوشش گیاهی بسیار بالا می باشد.
    کلیدواژگان: طبقه بندی رودخانه، پهنه های سیلابی، مدل رزگن، مدل هیدرودینامیکی HEC-RAS، رودخانه قره سو
  • محمدرضا ثروتی، رضا منصوری، منیزه قهرودی تالی، علی نعیمی صفحات 15-28
    مناطق ساحلی، محیط های پویا و تاثیرپذیری هستند که پیوسته خود را با اثر فرایندها و پارامترهای مورفوژنز دریایی از جمله کشندها، جریان های دریایی و امواج، فصول و دگرگونی های آب وهوایی سازگار می سازند. تغییر و تحول سریع خطوط ساحلی و سیماهای مورفولوژیکی یکی از ویژگی های مهم این مناطق به ویژه در اطراف بنادر و دیگر سازه های انسان ساخت می باشد. پایش تغییرات منطقه ساحلی و حفاظت از آن بخش بسیار مهم و حیاتی در برنامه مدیریت یکپارچه منطقه ساحلی به منظور دست یابی به توسعه پایدار است. خطوط ساحلی از پویاترین سیماهای سطح کره زمین به شمار می آیند. بنابراین، تهیه نقشه خطوط ساحلی و میزان تغییرات آن جهت برنامه ریزی و استفاده بهینه از سواحل امری بسیار ضروری است. منطقه مورد بررسی در این پژوهش کرانه های جنوب خاوری دریای خزر در اطراف بنادر امیرآباد و صدرا (نکاء) را دربرمی گیرد. در این پژوهش، به منظور پایش تغییرات خط ساحلی، از تصاویر ماهواره ای Landsat سری سنجنده های TM & ETM+ (5، 7 و 8) برای سال های 1987، 2001 و 2015 استفاده شده است. به منظور تعیین میزان تغییرات و جابجایی مکانی خط ساحلی در منطقه مورد مطالعه، ابتدا بهترین ترکیب باندی و تک باندی جهت استخراج خط ساحلی انتخاب گردید. سپس، جابجایی خط ساحلی را بر روی تصاویر مربوط به سال 1987، 2001 و 2015 در هشت نقطه و با رعایت فاصله 2000 متر اندازه گیری گردید. در ادامه، میزان رسوب گذاری و فرسایش در منطقه نیز محاسبه شد. یافته های پژوهش نشانگر آن می باشند که خط ساحلی طی دو دوره مورد بررسی یعنی از سال 1987 تا 2001 و از سال 2001 تا 2015 در بیشتر نقاط به سوی دریا پیشروی نموده و تنها در بخش های خاوری بنادر امیرآباد و صدرا (نکاء) دچار فرسایش شده است. بیشترین مقدار پیشروی و پسروی خط ساحلی از سال 2001-1987 به ترتیب 450 و 68 متر بوده است. درحالی که این مقادیر طی 2015-2001 به ترتیب برابر با 311 و 112 متر بوده است. همچنین، در مجموع میزان رسوب گذاری و فرسایش انجام شده در کرانه های منطقه از سال 2015-1987 حدود 69/5 کیلومتر مربع و 53/0 کیلومتر مربع بوده است.
    کلیدواژگان: جنوب خاوری دریای خزر، تغییرات خط ساحلی، رسوب گذاری، بندر امیرآباد، بندر صدرا (نکاء)
  • محمد شریفی پیچون، فاطمه زارع، کاظم طاهری نژاد صفحات 29-44
    در برخی از مناطق ایران مرکزی با وجود شرایط خشک و بیابانی حال حاضر لندفرمهایی قابل مشاهده اند که مربوط به فرایندهای یخچالی بوده و در گذشته بوجود آمده اند. هدف از این پژوهش، مطالعه و بررسی این نوع لندفرم ها جهت شناخت شرایط محیطی و اقلیمی گذشته در حوضه های خارج از کوه شیرکوه می باشد. روش اصلی مطالعه مشاهده مستقیم بوده و از نقشه های توپوگرافی، زمین شناسی، تصاویر ماهواره ای، نقشه رقومی ارتفاعی و دستگاه GPS نیز استفاده شده است. بعلاوه، از روش های رایت و پورتر در بازسازی آثار سیرکهای گذشته استفاده شده است. یافته ها حاکی از وجود لندفرمهایی است که در سیستم مورفوژنتیک یخچالی بوجود آمده اند. این لندفرمها در دو دسته لندفرمهای کاوشی یخچالی و تراکمی یخچالی مورد بررسی قرار گرفته اند. آثار کاوشی فعالیت یخچالهای گذشته در منطقه شامل 28 سیرک بزرگ و کوچک و دره های وسیع و عریض با عرض بعضا بیش از 200 متر در ارتفاع حدود 2000 متر است. مهمترین آثار تراکمی عملکرد یخچالها مورن های میانی، تیلیت ها و یخرفت های انتهایی است. مورن های میانی در منطقه مورد مطالعه به شکل تپه های تخم مرغی و مارپیچی شکل بوده و نزدیک به یک کیلومتر طول و حدود 20 متر ارتفاع دارند و از جمله تیپیک ترین آثار تراکمی یخچالها را در ایران مرکزی بوجود آورده اند. همچنین، تیلیت ها از دیگر آثار تراکمی فعالیت زبانه های یخی در منطقه هستند که به شکل تراسهایی در سمت چپ و راست دره رودخانه بر روی سنگ بستر اغلب به شکل دگرشیب و متناوب در دو سمت دره قرار گرفته اند و احتمالا مربوط به اولین دوره یخچالی می بوده که در دوره های دیگر توسط سیمان کربنات کلسیم سخت شده و به شکل کنگلومرا در آمده اند. یخرفت های انتهایی نیز در سه ارتفاع 1750، 1850 و 2170 متر وجود دارند که می تواند حاکی از وجود سه دوره یخچالی در منطقه باشد که از قدیم به جدید از شدت و قدرت آنها کاسته شده است. بررسی های دانه سنجی بر روی رسوبات میانی و تیلیت ها نیز موید منشا و فرایند زبانه یخچالی در منطقه است.
    کلیدواژگان: حوضه کذاب، مواریث یخچالی، مورن ها، تیلیت، کواترنر
  • محمدرضا نیکجو، ریحانه برومند، شهرام روستایی، ابوالقاسم امیراحمدی صفحات 45-63
    رشته کوه بینالود یک سیستم چین خورده ی تراستی است که در شمال شرق ایران واقع شده و جزو کوهستان های خشک و نیمه خشک کشورمحسوب میشود.دامنه های این رشته کوه به دلیل شرایط متفاوت لیتولوژیکی و مقاومت سنگها دربرابرهوازدگی و فرسایش ،ویژگی های اقلیمی و تغییرات شدید آنتروپوژنیک ازجمله کاربری اراضی،از موقعیت مناسبی جهت وقوع مخاطرات ژئومورفولوژیکی از نوع ناپایداری های دامنه ای می باشد بطوریکه این ناپایداری ها ازرخدادهای مکرری هستندکه تهدید بلقو های در زندگی، تجهیزات ،امکانات و راه های مواصلاتی و شبکه حمل و نقل در محدوده مورد نظر به شمار می آیند.روش مورداستفاده دراین پژوهش،تحلیلی و سیستمی است و به امکان سنجی خطر وقوع ناپایداری های دامنه ای می پردازد. در این راستا به منظور شناخت عوامل موثر در بروز ناپایداری های محدوده مورد مطالعه،11متغیراصلی نظیر،میزان شیب،جهت شیب لایه های زمین شناسی، واحدهای لیتولوژی، فاصله از گسل ، کاربری و پوشش زمین ، خطوط همبارش وسایر عوامل... برمبنای نقشه های پایه توپوگرافی 25000/1و نقشه های زمین شناسی 1:100000 و نقشه پوشش و کاربری زمین 1:50000 منطقه در سطوح مختلف مورد پژوهش قرارگرفت.در ادامه حوضه های هیدرولوژیک درقلمرو مطالعه مشخص شدکه مجموعا33 حوضه آبریز شامل 23 حوضه در دامنه شمالی و 10 حوضه آبریز در دامنه های جنوبی شناسایی شد.سپس بررسی متغیرها در منطقه بینالود به شکل زمین مرجع انجام گرفت ومدلسازی های جانبی تحلیل فضایی، در نرم افزار GIS تنظیم شدند لذانقشه های عامل تولید شده،با روش ANPارزیابی و با زیر نرم افزارجانبی expeart choice به شکل معیار های اصلی و زیر معیارها مورد وزن دهی قرار گرفته وسرانجام این نقشه هادر نرم افزار GIS بامنطق فازی و عملگرجمع فازی،با چهار درجه خطر کم ، خطر متوسط ، خطر زیاد ، و خطر بسیارزیاد مورد همپوشانی و پهنه بندی قرارگرفتند.طبق نتایج حاصل ازاین پژوهش شیب موثرترین عامل در بروز ناپایداری های دامنه ای در هردوسوی دامنه های بینالودشناخته شد و با توجه به جنس سازند زمین شناسی بیشترین تکرار فراوانی لغزش ها در دامنه های فیلیتی و سیلتی دامنه ی شمالی بینالود،وریزش ها در مارن های آتشفشانی دامنه های جنوبی رخ میدهدو بهترین راهکار مدیریت محیطی در جلوگیری و کاهش اثرات سوء خطر ناپایداری های دامنه ای رشته کوه بینالود ، تعیین پهنه های آسیب پذیرازخطر،آمایش سرزمین و استخراج قابلیت اراضی وجلوگیری از تغییرکاربری زمین بر مبنای نتایج مستخرجه می باشد.
    کلیدواژگان: ناپایداری دامنه ای، مدل ANP، بینالود، رویکرد مدیریتی
  • زهرا خان بابایی، ابراهیم مقیمی، مهران مقصودی، مجتبی یمانی، سیدکاظم علوی پناه صفحات 64-78
    مشاهدات و تفسیر اشکال رسوبی- ژئومورفیک رودخانه ها در طول سیلاب های شدید و پس از آن، برای درک بهتر مکانیسم واکنش تغییرات رودخانه، اساسی می باشد. از جمله پاسخ های ژئومورفولوژیک رودخانه ها به سیلاب می توان به گسترش کانال ، حمل و نقل و رسوب مواد بسیار دانه درشت، تغییرات عرض پهنه های فرسایشی و تراکمی ، فرسایش ساحلی کانال و ایجاد نهشته ها و اشکال رسوبی در بستر و حاشیه رودخانه ها اشاره کرد. هدف از انجام این مطالعه، شناسایی اشکال رسوبی و مورفولوژیک رودخانه های کوهستانی بالادست سد ایلام در پاسخ به سیلاب شدیدی که در آبان ماه سال 94 در استان ایلام اتفاق افتاد می باشد. برای نیل به این هدف، بازدیدهای میدانی از 100 سایت (هم در سطح آبراهه های بالادست و هم در رودخانه های اصلی منطقه مورد مطالعه) به منظور جمع آوری اطلاعات کیفی در فرآیندها (به عنوان مثال انتقال رسوب، فرسایش ساحلی) که مسئول تغییرات مورفولوژیک است، صورت گرفت. با استفاده از روش توصیفی- تطبیقی، تجزیه و تحلیل رسوبات سیلابی از طریق بررسی خصوصیات کیفی بافت و ساختار نهشته های سیلابی انجام شد. انواع مختلفی از نهشته ها و رخساره های سیلابی به عنوان اثرات مشخصه سیلاب شدید ایلام ثبت و با استفاده ازGPS تعیین موقعیت شد. نتایج حاکی از وجود سه نوع نهشته رسوبی(تپه تخته سنگی، نهشته طولی شنی تخته سنگی و نهشته جانبی شنی تخته سنگی) و یک نوع از اشکال روساحلی(باریکه تخته سنگی) در آبراهه های کوهستانی و چهار نوع نهشته رسوبی(نهشته طولی، نهشته مورب، نهشته مرکب جانبی و نهشته دماغه ای) و یک نوع از اشکال روساحلی(پشته شنی) در رودخانه های اصلی موردمطالعه بود. همچنین توالی خاص فضایی از اشکال رسوبی در امتداد رودخانه های کوهستانی پیدا شد، به طوری که ابتدا تشکیلاتی از تپه و باریکه قلوه سنگی ایجاد شده، سپس این اشکال توسط نهشته های طولی و جانبی در بازه های پایین تر جایگزین شده بودند.
    کلیدواژگان: رخساره های سیلابی، تغییرات مورفولوژیک، سیلاب شدید، سد ایلام
  • مرتضی قراچورلو، فریبا اسفندیاری، علی دلال اوغلی صفحات 79-98
    این پژوهش با هدف آگاهی از کم و کیف روابط فضایی بین پارامترهای ژئومورفولوژی و فراوانی پوشش گیاهی در حوضه های آبخیز ارسباران (سه حوضه ناپشته چای، ایلگینه چای و مردانقم چای) انجام گرفت. در این راستا با توجه به اهمیت زیاد مقیاس در مطالعات فیتوژئومورفولوژی، پی گیری این روابط در دو مقیاس حوضه و زیرحوضه ها مورد تاکید قرار گرفت. داده های مورد استفاده شامل تصویر ماهواره ای لندست و مدل رقومی ارتفاع SRTM بود که به ترتیب شاخص گیاهی NDVI به عنوان متغیر وابسته و 28 پارامتر ژئومورفومتری به عنوان متغیرهای مستقل از آن ها استخراج گردید. پس از نرمال سازی لایه های رستری متغیرها در دامنه صفر تا یک، آزمون روابط رگرسیونی چندمتغیره فضایی به روش گام به گام بین متغیرهای ژئومورفیک و فراوانی پوشش گیاهی در محیط نرم افزاری SAGA انجام شد. نتایج گام های رگرسیونی نشان داد که 8 پارامتر عمق دره، شاخص موقعیت توپوگرافی، ارتفاع، شیب، موقعیت دامنه، شاخص جهت شیب، تحدب سطح زمین و انحناء عمومی، مهم ترین متغیرها در تبیین تغییرات فضایی پوشش گیاهی می باشند. نتایج نهایی تحلیل های رگرسیونی حاکی از وجود بهترین مدل رگرسیونی در حوضه آبخیز مردانقم چای با ضریب تعیین 32/0 و ضعیف ترین مدل رگرسیونی در حوضه آبخیز ناپشته چای با ضریب تعیین 11/0 بود. حوضه ایلگینه چای با داشتن شرایط بینابین از مدل رگرسیونی با ضریب تعیین 21/0 برخوردار بود. اما در مقیاس زیرحوضه نتایج حاصل دلالت بر وجود تفاوت قابل توجه بین زیرحوضه ها و بین زیرحوضه ها و حوضه ها به لحاظ شدت و ضعف روابط فضایی داشت. بیشینه ضرایب تعیین برابر با 42/0، 51/0 و 62/0 و کمینه آن ها برابر با 08/0، 15/0 و 13/0 به ترتیب در زیرحوضه های شاخص ناپشته چای، ایلگینه چای و مردانقم چای گویای این تفاوت ها بود. این تفاوت و تمایز علاوه بر این که به بهبود فهم روابط فضایی ژئومورفولوژی و پوشش گیاهی در مقیاس زیرحوضه نسبت به مقیاس حوضه اشاره داشت، اولویت بندی زیرحوضه ها را به لحاظ حساسیت فیتوژئومورفیک میسر ساخت.
    کلیدواژگان: رگرسیون فضایی، پارامتر ژئومورفیک، پوشش گیاهی، مقیاس، ارسباران
  • ملیحه باتجربه، عادل سپهر، سید رضاحسین زاده صفحات 99-115
    تنوع زمینی مرهون تفاوت در خواص سنگ مادری، شرایط اقلیمی و حساسیت پذیری لندفرم ها است. در این پژوهش با هدف شناسایی عوامل تاثیرگذار بر تنوع زمینی، نقشه تنوع زمینی شهرستان مشهد بر پایه حساسیت پذیری لندفرم تهیه شده است. این مطالعه مبتنی بر دو روش مجزا شامل روش همپوشانی لایه ها در سیستم اطلاعات جغرافیایی و روش ماتریس تصمیم ویکورصورت گرفته است. در گام اول پس از تعیین شاخص ها لایه های اطلاعاتی از فرمت وکتوری به رستری تبدیل شدند، سپس تمامی لایه های رستری امتیازدهی و طبقه بندی مجدد صورت گرفت، در ادامه با ادغام لایه ها نقشه تنوع زمینی تهیه گردید. نتایج این مرحله نشان داد با افزایش میزان حساسیت پذیری در منطقه میزان تنوع زمینی نیز افزایش می یابد، بطوریکه بالاترین میزان تنوع زمینی در نیمه شمالی شهرستان عمدتا بر روی سازند های آهکی و دولومیتی مزدوران قرار گرفته است. در گام دوم با استفاده از الگوریتم تصمیم گیری ویکور، ابتدا از هر معیار نسبت به لایه پلیگونی طبقات ارتفاعی و دهستان ها میانگین گرفته شد و پس از تشکیل ماتریس تصمیم و نرمال سازی ماتریس اولیه، مقدار مثبت و منفی ایده آل محاسبه و با استفاده از مقدار مثبت و منفی، میزان سودمندی و تاسف مشخص شد و در نهایت با محاسبه شاخص ویکور پهنه بندی تنوع زمینی در سه گروه (زیاد، متوسط و کم) انجام و نقشه تنوع بر اساس رتبه شاخص ویکور برای طبقات ارتفاعی و دهستان ها استخراج شد. نتایج حاصل از مدل ویکور با واقعیت انطباق بیشتری داشته، به طوری که مشاهدات میدانی موید آن است به همین دلیل بالاترین میزان تنوع زمینی در محدوده دهستان کارده و ارتفاعات بین 1500 تا 2000 متر قرار گرفته است. در نهایت سه نقشه تنوع زمینی ساخته شده با هم مقایسه شدند. در هر سه نقشه تنوع، نواحی که دارای بیشترین تنوع زمینی بوده دارای انطباق بالایی می باشند.
    کلیدواژگان: تنوع زمینی، حفاظت زمینی، میراث زمین شناسی، حساسیت لندفرم، روش ویکور
  • صیاد اصغری سراسکانرود صفحات 116-132
    هدف این تحقیق تحلیل عوامل موثر بر شکل گیری الگو و دینامیک مجرا در محدوده مورد مطالعه رودخانه کلقان چای و ارزیابی قدرت رودخانه و اثرات آن بر مورفولوژی مجرا تحت تاثیر عوامل و اقدامات انسانی در تغییر شکل مجرا می باشد. تصاویر ماهواره ای، نفشه های توپوگرافی، نقشه های زمین شناسی، داده های هیدرولوژیکی جریان، داده های مستخرج از مدل رقومی ارتفاع و داده های مطالعات صحرایی داده های تحقیق را تشکیل می دهند، جهت رسیدن به هدف تحقیق، از روش های تحلیل قدرت رودخانه، قدرت مخصوص رودخانه، شاخص های ضریب خمیدگی، زاویه مرکزی و تحلیل سینوسی مسیر برای تحلیل دینامیک و الگوی مجرا استفاده شده است. نتایج روش های مختلف نشان داد که شکل گیری الگو و دینامیک مجرا در محدوده مورد مطالعه تحت تاثیر ویژگی های فرایندهای هیدرولوژیکی ناشی از فرایند تدارک دبی و دبی رسوبی، مقاومت لیتولوژیکی بستر و کنارهای های رودخانه می باشد و نقش عوامل انسانی به صورت تصرف و اشغال بستر رودخانه به شکل ایجاد باغات و مزارع و همچنین برداشت منابع شن و ماسه از بستر رودخانه می باشد. نتایج تحلیل قدرت سیلابی و قدرت مخصوص رودخانه نشان داد که با کاهش عرض معبر رودخانه، قدرت رودخانه افزایش می یابد، و قدرت سیلابی رودخانه به ویژگی های مورفولوژیکی رودخانه بستگی دارد. نتایج این تحقیق می تواند در شناسایی بازه های حداکثر توان رودخانه و بازه های تحت تاثیر فرسایش رودخانه ای استفاده شود.
    کلیدواژگان: دینامیک مجرا، الگوی رودخانه، قدرت رودخانه، رودخانه کلقان چای
  • سیاوش شایان، هدیه دهستانی، محمد مهدی حسین زاده صفحات 133-147
    کشور ایران با استقرار در منطقه خشک و نیمه خشک همواره از نظر کمی و کیفی با مشکل کمبود منابع آب رو به رو است. بر همین اساس نیاز به تدابیر مدیریتی برای این منابع محدود احساس می شود. از جمله روش های مدیریتی مدیریت منابع آب و انتقال این دانش جهت استفاده کاربران طبقه بندی رودخانه ها است. رودخانه خرم آباد یکی از مهترین رودخانه ها و منابع آبی در غرب کشور ایران در یک حوضه کوهستانی قرار گرفته است. این رودخانه به عنوان یکی از شریان های حیاتی شهرستان خرم آباد به شمار می رود. لذا در مباحث مدیریت منابع آب به این رودخانه توجه ویژه ای شده است و پژوهشهایی صورت گرفته است اما با دیدگاه مدیریت محیطی و با بهره گیری از دانش ژئومورفولوژی نبوده اند. یکی از ابزارهای مهم مدیریت منابع آب این منطقه طبقه بندی ژئومورفولوژیک رودخانه ها است. به همین جهت در این پژوهش بر اساس سه فاکتور چشم انداز، الگوی رودخانه و محدودیت بستر رودخانه خرم آباد و با بهره گیری از مشاهدات میدانی، تصحیح هندسی و موزاییک نمودن تصاویر ماهواره ای P5 مربوط به حوضه رودخانه خرم آباد، تهیه مدل ارتفاع رقومی و روش خوشه بندی در نرم افزار SPSSالگویی برای طبقه بندی این رود و رودهای مشابه در سایر مناطق جغرافیایی کوهستانی تهیه و ارائه شد. بر اساس این الگو رودخانه خرم آباد به چهار طبقه تقسیم شد. در این طبقه بندی از بخش های نه گانه رودخانه، بخش های 2،4،5و6 در طبقه اول، بخش های 7،8 و9 در طبقه دوم، بخش 3 در طبقه سوم و بخش 1 در طبقه چهارم قرار گرفتند. فاکتور اصلی تفکیک این بخش ها در طبقه بندی ها، فاکتور چشم انداز بود. هر چند که در بخش سوم (طبقه سوم) فاکتور شریانی بودن رودخانه، عامل تفکیک بوده است. این طبقه بندی از رودخانه مورد مطالعه می تواند به کاربران و برنامه ریزان منابع آب کمک کند تا با صرف هزینه و زمان کمتر و دقت بیشتر، رودخانه ها را دسته بندی و برای امور مدیریتی از آن بهره گیرند.
    کلیدواژگان: طبقه بندی رودخانه ای، ژئومورفولوژی رودخانه ای، مدیریت محیطی، رودخانه خرم آباد
  • رفعت شهماری صفحات 148-165
    در تحلیل مفهوم نو زمین ساخت مناطق سطح زمین، بیشترین تمرکز بر مطالعه فرآیندهای پویا و اثرگذار بر شکل دهی یا تغییر شکل لندفرم ها و پدیده های زمین می باشد. از این رو، اشکال ژئومورفولوژیکی در برابر فعالیت های زمین ساختی بسیار حساس بوده و در اثر این حرکات تغییر می کنند. هدف از این پژوهش بررسی وضعیت نو زمین ساخت با استفاده از شاخص های ژئومورفولوژیکی همچنین تحلیل نقش عوامل تکتونیکی در شکل گیری و تحول مورفولوژی محدوده تحقیق می باشد.. برای ارزیابی و تحلیل فعالیت های نو زمین ساختی در هر یک از این حوضه ها از طریق شاخص های ژئومورفولوژی از جمله: شاخص شکل حوضه (Bs)، شاخص عدم تقارن حوضه زهکشی (Af) شاخص تقارن توپوگرافی عرضی (T)، شاخص منحنی هیپسومتریک (Hc)، شاخص پهنای کف دره به ارتفاع آن (Vf)، شاخص پیچ و خم رود (S)، شاخص گرادیان طولی رودخانه (SL) استفاده شده است. نتایج به دست آمده طی چندین مرحله کار میدانی و ارزیابی شاخص های ژئومورفولوژی، نشان دهنده وجود حرکات نو زمین ساخت فعال در حوضه ها به صورت فراخاست و عملکرد سیستم گسلی می باشد و نشانه این است که همه حوضه های مورد مطالعه دارای فعالیت شدید نو زمین ساختی می باشد و فقط از نظر شاخص Af در وضعیت غیرفعال قرار دارند.
    کلیدواژگان: نوزمین ساخت، شاخص های ژئومورفولوژیکی، استان گیلان، کوه های تالش
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  • Mh Rezaee Moghadam, Mr Nikjoo, M. Yasi, M. Rahimi Pages 1-14
    Introduction Streams typically have similar suites of channel morphologies, with repeatable patterns of occurrence that have resulted in numerous classification efforts (Roper et al., 2008: 417-427). Recent approaches for river classification focus on watershed analysis related to land management and stream restoration, using a hierarchical approach that nests successive scales of physical and biological conditions and allows a more holistic understanding of basin processes (Shroder, 2013: 739). One of the most widely used hierarchical channel classification systems was developed by Rosgen (Shroder, 2013: 742). In the current study, Gara Sou river channel planform are studied by using Rosgen geomorphological model in combination with HEC-RAS model.
    Materials and methods This study is based on fieldworks and topographic maps of scale 1: 2000 (Ardabil Regional Water Authority). To determine the friction coefficient distribution of channel and floodplain, land cover maps was generated using Google Earth satellite imagery. Rosgen (1985, 1994, and 1996) hierarchical system was used to analysis of river channel morphology. The Rosgen system uses six morphological measurements for classifying a stream reach-entrenchment, width/depth ratio, sinuosity, number of channels, slope, and bed material particle size. In this research, some of these parameters were calculated using HEC-RAS hydrodynamic model. For steady, gradually varied flow, the primary procedure for computing water surface profiles between cross-sections is called the direct step method. The basic computational procedure is based on the iterative solution of the energy equation. Given the flow and water surface elevation at one cross-section, the goal of the standard step method is to compute the water surface elevation at the adjacent cross-section. The flow data for HEC-RAS consists of flow regime, discharge information, initial conditions and boundary conditions (HEC, 2010).
    Results and discussion According to calculations made in seven reach has been in class C and E, hierarchical model Rosgen. Gara Sou River in class C has a wider and shallower channel and floodplain width significantly developed. Gara Sou River in class E also has a deep and narrow channel (width to depth ratio) but floodplain width developed. In reach (1) floodplain width due to low geological control variable. In this reach was due to power of river, the bed river is cobble and gravel that leads to the river bed is in the Armoring range. With regard to slope variables and bed material, it is placed in the class C. in this class have a mean energy and high sediment load. Energy waste by meandering, bed forms (Pool- Riffle) and vegetation occurs. In the reaches of 2, 3, 4 and 5 width floodplain will be a significant development. In the reaches type of bed river is changed to gravel and sand and more of gravel and sand are. River slope in this reaches are between 0.02 and 0.039. In this reaches (2, 3, 4, and 5) river in the most part located class of C4b Rosgen model and only in some sections of the river have been E4b class. Average width to depth ratio is calculated 16.14 for the total reaches. In this reaches riparian vegetation are mostly dense shrubs that this high density of riparian vegetation plays an important role in the stability of the banks river in this reaches. In the end of reach (5) and reach (6) river slope between 0.001 and 0.02 is located and bed River is sand that often makes the river in this section in class C5 in hierarchical Rosgen model. Average width to depth ratio is calculated 15.46 for the total reaches. In reach (7) river slope to less than 0.001, but the bed river is still sand. According to the results, the major part of this reach is located class C5c and only in small portions cross sections of the E5 is placed class.
    Conclusion In this study, Gara Sou River channel was classified using geomorphological Rosgen model on the first and second levels. Despite the widespread use Rosgen model, has been criticized by some researchers. Problems with the use of the classification are encountered with identifying bank full dimensions, particularly in incising channels and with the mixing of bed and bank sediment into a single population. Gara Sou River in parts of Type E has a low sediment supply, average potential bank erosion control and vegetation are very high. The rivers carry sediment are very efficient and river is low energy, loss of energy through the meandering, bed forms and vegetation occurs. Also this river in parts of the Type C has a high sediment supply, very high potential bank erosion control and vegetation is very high. In fact, vegetation combined with the bank erosion, determines the amount of lateral adjustment and sustainability of this river.
    Keywords: Stream Classification, Flood prone area, Rosgen model, Hydrodynamic HEC-RAS model, Gara Sou River
  • Mr Servati, R. Mansuori, M. Ghahroodi, A. Naeimi Pages 15-28
    Introduction The coast is a dynamic environment continually adjusts to the effects of weather, tides, seasons and climate change. The coastal area cannot withstand too much misuse it is inherently unstable and liable to change. Rapid changes in coastlines and morphological aspects an important feature of these areas, particularly around ports and other structures are manmade. Protection of ocean and marine coastal regions is a vital part in any coastal management program for sustainable development. The coastline is the most dynamic aspects of the Earth's surface. Thus, mapping the coastline and the changes it is very necessary for planning and efficient use of the beaches. On the other hand, in our modern world, coastal engineering sciences and assessment of coastal sediments and erosion are considered to be vital elements in management of national coastal areas. A large part of sediments of Caspian Sea coast are subject to erosion as a result of environmental forces (fluctuations in sea level and coastal waves and currents as well as wind). The rate and severity of erosion hazards varies depending on the morphological and geography and hydrodynamic properties of coastal areas. The case study in this research is situated at coordinates of geographical longitude from 53ú, 10ó, and 00ð up to east 53ú, 24ó and 00ð and geographical latitude 36ú, 47ó, and 00ð up to north 36ú, 52ó, and 00ð the southeast coasts of the Caspian Sea on the ports of Amirabad and Neka in the East of Mazandaran Province.
    Methodology Change detection helps in ascertaining shoreline trend analysis and its future prediction.The main purpose of this research is assessment of coastline changes in the south east coasts of the Caspian Sea during 1987-2015. Thus, satellite imagery (Landsat 5, 7 and 8, TM sensor for June 1987 with bands 1 to 4, ETM [Landsat 7] for July 2001 with bands 1 to 8 and ETM [Landsat 8] for August 2015 with bands 1 to 11), topographic maps (with scale: 1:50000 and 1:250000) and geographical information system software in Arc GIS 10 and Erdas Imagine 9.1 software, have been used. The use of satellite images is an effective technique for study and assessment the occurred changes in the coastal zone. So, in this study, in order to monitoring changes in the coastline, Landsat satellite images (TM and ETM Sensors) for 1987, 2001 and 2015 have been used. In order to determine the amount of change in the coastline in the study area, the best band combination and one band was chosen to extract the shoreline. Then, the change and move coastline on the images of 1987 and 2001 and 2015 in eight points and was measured by observing the distance of 2000 m. Then, the amount of sedimentation and erosion in the area were also calculated.
    Result and Discussion The results indicated who the coastline during the period under review, from 1987 to 2001 and from 2001 to 2015 is progress to the sea in the most parts and only in the eastern ports of Amirabad and Neka eroded. The greatest amount of progress and retreat of the shoreline of the years 2001-1987, respectively, are 450 and 68 m. While these values during 2015-2001, respectively 311 and 112 m has been. Also, the rate of sedimentation and erosion in the area of 1987-2015 respectively has been about 5.69 and 0.53 square kilometers.
    Conclusion The results of this research show that most of the changes occurred in the study area in the period 2001-2015. Analyzing satellite images of the study area show that due to the construction and development of the ports of Amir Abad and Sadra drastically changed, so that the coastline in most parts toward of the sea progressed and main phenomenon in the study area has been sedimentation. The interpretation of satellite image data indicates that areas at opposite sides of the Amir Abad and Neka ports had different responses to depositional and erosion processes. Beach modification impacts have aggressively developed at the central part of study area groynes at the Amir Abad port have caused sediment accretion at the west side but erosion processes could develop as the beach retreats on the east side. The maximum progress amount in coastline of the study area is occured in the western part of Amir Abad port during the period 2001-1987, which at 450 meters has been changed. Also, the results show that significant volume of the sedimentation is deposit in west section of the Amir Abad and Neka ports. But, east section of these ports is faced with erosion. Moreover, the most change during the period time studied is related with volume sedimentation in the western section of Amir Abad and Neka ports that it somewhere reaches to 130 hectare. The results of this research can be applied in development plans for engineers and issues in the integrated coastal zone management for study area.
    Keywords: South East of the Caspian Sea, Coastline Changes, Sedimentation, Amir Abad Port, Sadra Port
  • M. Sharifi, F. Zare, K. Taherinejad Pages 29-44
    Introduction Present Landform has been affected by climate conditions over time. Therefore, they show the characteristics of sequence and periodicity of it in the past. According to, using the landforms, we can reconstruct climate condition and its changes. Geomorphological glacier landforms are one the most terraces that show the changes of climate in the past. Nevertheless, Central of Iran has located in a dry region at the moment, especially central of Iran, but there are some specified landforms in the region that represent spreading the glacier in the center of Iran in Pleistocene. These includes abrasive and depositional relicts. The goal of the study is the investigating of present landforms in the central of Iran-Kazab Basin in the west of Yazd City- to know processes that have created them in the past, especially the landforms that have created by glaciers. Kazab basin has located in the south-west of Yazd city in the west slopes of Shirkuh Mountain along 31° 53´ to 32° 7´of northen latitudes and 53° 52´ 42" to 54° 7 of eastern longitudes.
    Materials and Methods This research has been performed on basis of field studies and direct observation of glacial landforms. But, we studied topographical and geological maps, DEM, satellite images as well as aerial photographs, at first. The resulted information of the maps controlled with GPS System in the field. Then, we measured some boulders and pick up some sample of sediments and examine them in the geomorphological laboratory in the department of geograpgy in Yazd University.
    Discussion and results Findings show many landform that has created by a glacier morphogenetic system. These landforms was categorized in two classes includes abrasive and deposition processes. The relicts of abrasive of the glacier activity involve 28 small and great cirques and some wide valleys as well that the width some of them reach to 200 meters in height 2000 meters. The most important of deposition traces of the glacier in the region involve tills, moraines, tillite and erratic stones. We have discussed both classes in more detail in the following: ◦abrasive traces
    -Cirques: using topographical map and its contours characteristics we marked cirques on the map. Cirques appear on the map with stretched contours as sinusoidal form. Accordingly, we defined 28 small and great rcirques, and then checked them on the field using GPS system. More of them have laid between 2000 to 2500 meters height.
    -Glacial valley: A valley carved by glaciers is normally U-shaped. A glacial valley becomes visible upon the recession of the glacier that forms it. Glacier valleys are the biggest abrasive forms glacier in mountains that become broad towards peak. Because a glacier has a much greater viscosity and cross section than a river, its course has fewer and broader bends, and thus, the valley becomes straighter and smoother. In the Kazab there are 3 wide valleys that the Hamane Valley, in the west of the basin, is the greatest so that the width of it reaches about 200 meters. •Depositional traces
    -Tills and moraines: Moraines are landforms created directly by glacier. In other words, moraines are a formation composed of unsorted and unbedded rock and soil debris called till, which was deposited by a glacier. After the retreat of a glacier the moraines remain as prominent features of the topography. Present moraine often have deposited in Pleistocene epoch. Kazab moraines usually have lay within main valley and include different sizes. They often observe between 1750 to 2050 meters as lateral, medial and terminal moraine. The medial moraines in the region are shown spiral hills with about one kilometer length and 20 M height. Besides, they are one of the most typical relicts of glacier in the center of Iran. The most properties of moraine are nonhomogeneous, angular, and have vertical direction to the river.
    -Tillite: Sedimentary rock that consists of consolidated masses of unweathered blocks (large, angular, detached rock bodies) and glacial tills (unsorted and unstratified rock material deposited by glacial ice) in a Conglomerate form. The presence of tillites in a region provides evidence of former intense and widespread glaciation; recent tillites (about 10,000 years old) can be directly connected with glaciation, and Pleistocene tillites (10,000- 2,500,000 years old) can be convincingly related to glaciation. In other words, tillites are a kind of conglomerates that their sediment is created by glaciers. The rocks are deformed, poorly sorted and comprise quartz, feldspar and mainly sedimentary lithoclasts. The pebbles are relatively nonhomogeneous regarding their size. In the Kazab basin, tillites are observed in the left and right of the valley. In the region, tillites has located as terraces on both besides the river channel on the bedrock. They probability belong to the first glacial period that in another glacial periods sediments have stick together by calcium carbonate and established conglomerate and also has covered by tills and slopes sediment, they have remained unweather till now The height of the tillite layer in the Qezrabad valley is about 10 meters.
    -Erratic stones: An erratic is a boulder transported and deposited by a glacier that differs from the size and type than the bedrock or native rock to the area in which it rest. Erratic stone are useful indicators of of former ice flow, and setting of glaciers. Erratic stones in the Kazab valley has located in three different height like 1750, 1850 and 2170meters that could show represent three glacial periods in the region by reducing their intensity from old to new.
    Conclusion Results show glacial traces for three periods In the Kazab basin in Pleistocene. Tillites and moraines located on them show two glacial periods at least, but the erratic stones, which has located in three different height indicates to three glacial periods. Besides, tills, moraine, tillites, wide walleyes, and cirques affirm glacial prevailing in the region. Nevertheless, granulometry studding on the medial moraines as well as tiillites confirm glacier processes in the region too.
    Keywords: Kazab, glacier, Geomorphological relicts, Tillite, Quaternary
  • Mr Nikjo, R. Boromand, Sh Roostaei, A. Amirahmadi Pages 45-63
    Introduction
    Binalood Mountain Range is a trusted system located in the north east of Iran. It is part of the dry and semi-arid mountains of the country. The slopes of this mountain range due to different lithological conditionsand rock resistance against weathering and erosion, climatic characteristics and severe changes anthropogenic, including land use, has a good position for occurrence of geomorphological hazards there are some kinds of domain instability, especially these instabilities there are frequent events that poke a threat to life, equipment, facilities and transportation routes within the desired range. According to statistics, slippery slopes and various types of instability in the mountainous areas of the Binalood Zone since the 1370 have been exacerbated. Therefore, it makes doubling the importance of addressing the subject. According to field studies in the northern and southern slopes of Binaloud, the exacerbation of the risk of mass movements of the range, and in particular of the risk of slipping, has a widespread frequency and range than other environmental and geomorphic hazards. Factors such as grazing over the livestock capacity and tract created by kicking the soil caused by the movement of the livestock, falling slopes, with unconventional horticulture on the terraces of alluvium and on steep slopes, Severe land use changes, especially in sloping slopes, are one of the most important factors in day-to-day and the intensification of sloping movements and the occurrence of destructive currents in the northern and southern slopes of Binalood. Binalood mountain range The geographic location of the mountain range is semi-arid with a length of 143.75 km With the northwest trend - south-east extending from south east and from Quchan to northeast of Neyshabur.
    Methodology
    The research method used in this research is an analytical and inductive system And to the feasibility of occurrence of sloping instabilities as one of the most important geomorphic hazards in the northern and southern slopes of Binalood Which has a devastating impact on the settlements of the human communities .in the region In order to identify the factors influencing this phenomenon, 11 variables such as variables Slope, slope of geological layers, lithology units, distance from fault, land use and coverage, consistent lines and homogeneity, altitudes and other factors .. Based on the topographic map of 1/25000 at different levels of natural and human studies, In this regard, firstly, the hydrological basins in the study area were found to be in the realm of research in total of 33 catchment areas including 23 basins in the northern slope and 10 catchments in the southern slopes were identified.
    Results And Discussion
    Investigating the variables in the Binaloud region in the form of reference land, and lateral spatial modeling were arranged in GIS software and processed in Autocad software Therefore, the produced production maps are evaluated by the ANP method and subjected to the following expeater selection software in the form of main criteria and sub criteria. In the ANP method, we accurately analyzed the parameters in pairs and compared to the 11 variables of the present study, the results showed that the parameters of slope, altitudes, lithology units, faults, land use and land cover, and .... Respectively, have the highest gained weight. Finally, these maps were overlapping and zoning in GIS software with fuzzy logic and fuzzy aggregate operator. The hazard zonation map generated from this model, as a reference map, is adapted to the initial map prepared through field observations, spatial coordinates with GPS, and aerial photo interpretation. Its results were analyzed and analyzed from the perspective of environmental management.
    Conclusion
    Finally, based on the statistical results extracted from these maps, testing the assumptions about the probability of occurrence of slopes and especially landslides And its effect on environmental management, using Spearman and Kendall tests in SPSS software, the results of which prove the hypotheses With a probability higher than 95%. According to the results of this study, the gradient is the most effective factor in the incidence of domain inconsistencies in each other and due to the geologic form of the formation, the most frequent occurrence of landslides occurs in the northern and southern silty and subtropical slopes of the southern slopes of the southern slopes. And the best environmental management approach to reduce the risk of insecurity in the Binaloud Mountain Range, to identify vulnerable zones of danger, land allocation, and land use capability and to prevent land use change based on sub-optimal results.
    Keywords: Domain Instability, ANP Model, Binalood, Management Approach
  • Z. Khambaba, E. Moghimi, M. Maghsuodi, M. Yamani, K. Alavaipanah Pages 64-78
    Introduction Observation and interpretation of geomorphic and sedimentary features and processes conducted after and possibly during the flood event are fundamental to developing a better understanding of the mechanisms responsible for channel changes Extreme flood events increase stream power and the rates of erosion and accumulation in the river channel. The geomorphological effect of a flood depends on the size of the stream, magnitude, and frequency of the flood event and on the physical properties of the channel, banks, and floodplain. In October 2015, following the occurrence of severe and sudden rainfall, three large and devastating floods occurred with a maximum instantaneous discharge of 230 m3 / s from 6 to 8 October in Ilam province. The floods caused major changes in the morphology of Ilam's main streams and rivers and caused various sediments and deposits in the bed and rivers of Ilam. Since few studies have been done in this field, this research was conducted with the aim of investigating the geomorphic sediment response of Mountain Rivers on the creation of flood landforms upstream of Ilam dam to severe flood events.
    Methodology 100 sites were studied in waterways of the upper Ilam dam drainage basin after flood. The shape, location, dimensions and deposits of large depositional forms (bars) were documented. The bars are regarded as mega forms, strictly connected with the alluvial sedimentary style. Smaller depositional forms were not investigated because their formation was controlled by local hydrodynamic conditions, and moreover, they were quite rare in the coarse-grained channels. All waterways were divided into two groups: streams and rivers. This subdivision was necessary because both qualitative and quantitative character of depositional forms appeared to be different in these systems.
    Results and Discussion Most of the depositional effects in mountain streams are concentrated within the channel. Boulder mounds are the most typical bar type in the upper reaches of streams. Deposition of coarse-grained material takes place during the flood peak in areas of lower stream power between the main current tracts. Gravel–boulder longitudinal bars dominate in the lower reaches of streams; these are distinctly elongated forms located within the channel. Gravel–boulder side bars appear in slightly sinuous reaches of stream channels. The bars exist close to both banks. Overbank depositional forms of streams are relatively rare. Boulder berms are characteristic of large floods. A boulder berm is a coarse-grained levee formed immediately above the bank crest, in the zone of large velocity gradients during the flood peak. Longitudinal bars are formed in the central part of river channels. Their plan form is elongate, oval or rhomboid. Large compound bars commonly develop in wide zones of nearly straight channel courses. Unit longitudinal bars result from deposition in crossover zones in the slightly sinuous channel. Longitudinal bars play a significant role in the process of braiding. They diverge the current and enlarged, compound bars lead to new channel growth. A diagonal bar is the most abundant and characteristic macro form from the group of side bars. Diagonal bars are typical of river channel reaches characterized by slight sinuosity. They exist alternatively close to both channel banks, immediately downstream from gentle bends. A side compound bar is the second type of the bar distinguished within the group of side macro forms. This is a large-scale bar that exists in the zones of channel widening. These bar types were only noted in channels with tendency for braiding. A coarse-grained point bar is the next characteristic type of side macro form. It differs from other side-type bars by location in the channel, morphology, and mode of accumulation. Point bars exist in sharp bends. A gravel levee is formed on the lowermost terrace, close to the channel bank. Sometimes its formation was caused by the stems of trees growing along the river channel. The basic feature of stream alluvium is that lithofacies type is weakly dependent on parent depositional form. Generally, deposits are characterized by: very coarse grain size, lenticular shape of beds and imbricated structure. All bar derived deposits of the main rivers studied represent one lithofacies assemblage. Gravel and boulder clast-supported beds with imbricated structure or are the most abundant lithofacies derived from the bars.
    Conclusion There is a relatively regular spatial succession of depositional processes and forms along the mountain streams. In the uppermost reaches, only erosion takes place. Depositional processes ensue downstream. Formation of boulder mounds and boulder berms take place first. These forms are replaced by longitudinal bars and side bars in lower reaches. One phenomenon was characteristic both of streams and main rivers: the zone of increased deposition always follows the zone of erosion. Moreover, the ratio of fluvial deposition is proportional to intensity of upstream erosion. Both texture and structure of mountain stream alluvium indicate very weak relationship with parent depositional form type. Generally, deposits are characterized by: very coarse grain size, beds are of lenticular shape and their structure is typically imbricated. The most abundant bar types of main rivers are represented by one lithofacies spectrum. The most common lithofacies are clast-supported gravel and boulders with imbricated structure.
    Keywords: Flood Facies, Morphological Changes, Extreme Flood, Ilam Dam
  • F. Esfandiyari, A. Dalaloghli Pages 79-98
    Introduction Special and sensitive role of vegetation cover in ecosystem sustainability and moderating hazards such as floods, erosion and pollution of water resources persuades us to understand the environmental variables affecting the growth and development of it. This issue particularly is important for susceptible mountainous catchments. In these environments, geomorphic variables as special representative of environmental factors have close and interweaved relation to vegetation cover. So, knowledge of the relationships between geomorphology and vegetation can help us to better manage and maintain the mountainous ecosystems. The understanding requires analysis the spatial relationships and scientifically accurate spatial modeling. In this regard, the emergence and development of remote sensing (RS) and geographic information system (GIS) have widely improved modelling the spatial variations of vegetation cover. However, a few issues that are fundamental and important in geomorphic-vegetation relations must be noticed. Maybe, the scale is the most important issue in phytogeomorphic researches. This study aimed to assess and determine the relationships between geomorphology and vegetation cover using spatial regression approach in Arasbaran catchments (3 catchments: Naposhtehchhay, Ilginehchay and Mardanqumchay). We have particular stress for effect the scale on the relations and comparison of predictive regression models in multiple scales based on catchment and subcatchment divisions.
    Materials and Methods Our approach is based on spatial multiple regression analysis between geomorphologic parameters and abundance of vegetation. In this regard, 27 geomorphomety parameters as independent variables and Normalized Difference Vegetation Index (NDVI) as the dependent variable were computed from Landsat imagery (ETM sensor) and digital elevation model (DEM) SRTM. First, preprocessing operations including atmospheric correction (noise reduction) and geometric correction were performed on the sattellite image. DEM is preprocessed by removal of sinks in GIS environment. After radiometric and geometric corrections, raster layers of geomorphic parameters extracted and prepared using GIS and SAGA softwares and NDVI layer computed using IDRISI software. Furthermore, determination and mapping the cathments and subcatchments performed by ArcHydro extension of GIS.Given the various scales of the variables, it was necessary to normalize the scale of data ( ) using the following formula: In the formula, x: raw value of the variable; min (x): minimum of the variable; max (x): maximum of the variable.We use the SAGA for performing the spatial multiple regression (stepwise method) with 0/01 signisicance level. We examine the regression relations in two scales: 1- catchments 2- subcatchments. Finally, we compare different spatial multiple ression models at 2 scale for selection of best models.
    Results and Discussion Initial results of showed that many of geomorphological parameters had significant relations with vegetation cover in spite of their low correlation coefficients. The results of rgression steps indicated that 8 parameters including valley depth, topographic position index, elevation, slope, slope position, transformed aspect, earth surface convexity and general curvature are the most important inependent variables in explaining the variance of dependent variable at catchment scale. The best linear regression model was abtained in Mardanqumchay catchment (R2= 0/32) in among regression models. In contrast, the weakest regression model is abtained in Naposhtehcay catchment (R2= 0/11) in among regression models. It appears that Ilghinehcay catchment have moderate phytogeomorphic conditions having moderate rgression model (R2= 0/21) in among regression models. It is found that there is a correspondence between ruggedness of catchments and prediction power and efficiency of the regression models. The results of regression analysis at subcatchment scale were significantly different. At this scale, best regression models observed with 0/42, 0/51 and 0/62 R2 values in Naposhtehchhay, Ilginehchay and Mardanqumchay, respectively. In contrast, weakest regression models observed with 0/08, 0/15 and 0/13 R2 values in Naposhtehchhay, Ilginehchay and Mardanqumchay, respectively. Hence, not only there are many differences among subcatchments, but there is considerable difference between catchments and subcatchments in the respect of intensity of relations between geomorphic parameters and vegetation cover.
    Conclusion Results of the research showed the geomorphic parameters including valley depth, topography position index, elevation, slope, slope position, transformed aspect, earth surface convexity and general curvature valley are the most effective variables in explaining the spatial variations of vegetation cover in Arasbaran catchments. The selected geomorphic variables, Wholly, are partly complete reflection of geomorphology of a site, not only keeping the relation between form and process, are the special representative of other environmental factors. Although significant portion of spatial variations of the vegetation cover could not be explained by final regression models at cathment scale, but the predictive models are valuable, considering the application of pixel-based spatial approach in regression analysis, in one hand and complex non-linear relationships between vegetation cover and geomorphology, in other hand. At subcatchment scale, some of these relations are stronger than catchment scale and regression models are more efficient, leading to inhance the understanding of relationships between geomorphology and vegetation. Furthermore, we can give preference to subcathments based on strength of regression relations (R2 rates), which determines the phytogeomorphic sensivity of them, in order to manage and support the mountainous ecosystems. It is concluded that important information about relationships between geomorphology and vegetation can be acquireed at multiple scales, simultaneously.
    Keywords: spatial regression, geomorphic parameter, vegetation cover, scale, Arasbaran
  • M. Batajrobe, A. Sepehr, R. Hoseiinzade Pages 99-115
    Geodiversity is a difference in the properties of rock, climatic conditions and landform susceptibility. Today, geological protection has been widely applied and mark as a new approach to protect geological heritage (Which is part of the natural heritage). In Iran not only the geological conservation methods have not been developed, the methods of evaluation and description of the geological heritage also has not been prepared. Thus, understanding the importance of these documents and preserve (what is called common heritage of humanity) is very essential. Conservation of nature and includes two varieties: Land variety and Biodiversity. In this regard, based on identifying the factors affecting terrestrial diversity, a map of land diversity of Mashhad city has been derived based on Landform's susceptibility. Therefore, based on the subjects described, land variety map of Mashhad province has been derived in present study to identify the factors affecting land diversity. In this regard, overlying and Vikor methods have been evaluated. Results show that the results of these methods are good agreement with each other.
    Results showed that as sensitivity increased, the land diversity is increased respectively. As the highest amount of land diversity is found in the northern half of the city which is mainly located on the limestone and dolomite formations. Results obtained from Vickor model are more consistent with reality. Because based on in situ measurements the maximum land diversity is found in areas of Kardeh village and the elevation ranges from 1500 to 2000 meters. •
    Based on the objectives described, quantitative-analysis methodology has been used. Firstly, literature review was conducted based on the papers, books reports and etc and primary data were collected and intendent indexes were selected. Secondly, geological, geomorphology and topography map were outlined. Also Digital Elevation Model (DEM) was used for deriving land form energy map (used for Geodiversity). Finally, geomorphology, geology and energy maps were used for extracting fragmentations model and NDVI and Land use maps used for deriving landform preservation map. In order to achieve the desired objectives, Google Earth, Global Maper, Arcgis and Vikor softwares used. As aforementioned, two different methods were used in present study (overlapping method and the Vikor decision matrix). In the first step, after selecting indicators, vector layers have been converted to raster. Then all raster layers have been rated and were reclassified and the land variety map derived by combining all layers. At the second step, using Vikor decision matrix method, the indexes were averaged based on aspect ratio, elevation and village polygons. After organize decision matrix and normalization of primary matrix, the ideal positive and negative values calculated and with use of these values.The profit and rate obtained finaly with counting vikor index,geodiversity zoning made in 3 group (high.average laws ) and based on vikor index rank geodiversity map extarcted for hight and villages category
    Results and discussion Sensitivity layer created shows that about 33% of Mashhad province classified as high sensitivity and about 60 and 7% of the remaining areas classified as medium and low sensitivity areas respectively. Also the preserve layer illustrate that about 47% of study area is classified as high protection, and the remaining areas classified as medium and low protection (about 36 and 16 percent respectively). By combining the sensitivity and protective layers, land variety map extracted which the results show that about 86% of Mashhad province classified as low variety (including residential and agricultural areas). Also about 9 and 5% present of case study region classified as mid variety and low variety regions respectively (including the northern half of the study region which is located over limestone and karst thick layers). Variety map which was extracted using Vikor method shows that Kardeh rural area and areas located at an altitude between 1500- 2000 meters classified as the highest variety. This result is consistent with the results of the first methodology •
    Overlapping method shows that as the sensitivity increased, land variety increased too. As the highest amount of land variety found in the northern half of the province which is located over limestone and dolomite constructions. The results of Vikor method show the good confirm with the reality, because in site measurements show that the highest amount of land variety located around the Kardeh rural and at an altitude between 1500- 2000 meters. Finally, the three land variety maps compared with each other. In each land variety maps, areas with high variety show a good agreement Also according to the results obtained from the Vikor model it can be concluded that in the karde village of Mashhad which has high geodiversity. We can develope geotourism with aproperiate planning and management. Moreaver, the city of Mashhad annually welcoming millions of tourists and pilgrims that can even be increased in number by creating geotourism sites in areas with high-diversity, also with revenuos from this items can play a determining role in sustainable development of area
    Keywords: Geodiversity, Vikor Method, GeoHeritage, Landform Conservation, Landform Sensitivity
  • S. Asghari Pages 116-132
    Introduction The Monitoring on route changes trend and geometric pattern of rivers is essential for identifying and evaluating eventual problems and risks in order to maintain and optimize utilization of natural resources and it is among the priorities of Geomorphology Studies. The purpose of this study is analysis of affecting factors in Kalghan Chai River and Assessment of river power and effects on the river morphology influenced by human actions is changing the river shape. The Kalghan Chai Basin is part of the Ghezel Ozen basins, which is the Garango River is its main drainage. This is located at the position 28° 46 to 30 46 east longitude and 34 37 to 46 37 north latitudes on the eastern slopes of the Sahand Mountains. In this research, studied region is range between Kalghan Dam to connect Garango River.

    Material and methods In study in order to achieve research goal were used techniques and different methods, materials of research are include of Satellite Image, Topographic map, Geological map, flow Hydrological data, data provided from Dem and field data. In this research were used methods of River Power Analysis, River specific power, Sinuosity Index, Central angle, Route Sinuosity in order to channel pattern and dynamic analysis. In order to study the river power and its effect on the erosivity, River discharge was calculated in different return periods. Then the river power was calculated by the following equation: The flow power can also be expressed in units of the bed surface if the width of the river (W) is divided, Therefore, in order to express the power of the river at any point, it is necessary to calculate the special power of the river, is calculated by the following equation:ω=γQS/W
    To study the shape and pattern of the river, coefficients Sinuosity Index, Central angle, Route Sinuosity were used. Then the Sinuosity Index size for each arc was calculated by the following equation:The center angles of the arches on each of the intervals were calculated using the following equation
    The sinuosity of the river route was also calculated using the following equation:
    Results and discussion The analysis of the characteristics of river meandering on the basis of Sinuosity Index showed that the Sinuosity Index of the study area was 1.31. And more than 90% of the curvature range is from 1.05 to 1.5, and the curvature is more than 1.5, 89% of the meandering of the study area. There are no curvatures of less than 1.05 and no more than 2 in any of the studied meanders. Therefore, the pattern of the river in study area is sinuosity. The sinuosity analysis of the river interval also showed that of the 20 interval studied, there is no Meandering interval, And 7 interval are straight pattern the rest of the interval has a sinuosity pattern. River Power Analysis showed which has the maximum River power of the Sections 20, 21 and 22, the lowest of river power are at Sections 11, 12, 13, 14 and 15. The lowest of specific river power in the sections of 19, 21 and 6. And the maximum river power in the section of 9.
    Conclusion Results indicated that forming of channel pattern and dynamic in studied area was controlled by hydrological processes cased flow and sediment discharge, lithological resistance of river bed and sides and the role of human factors for capture and occupation of the river bed to create gardens and farms as well as at some sections the main factor shaping is the Chanel of removal of sand from the river bed. The results of flood power and specific power analysis showed by reducing the width of the river crossing, river power increases, and the flood power depends on morphological characteristics of the river The results of this study can be used to identify of interval Maximum River power and interval affected by river erosion.
    Keywords: Channel Dynamic, River Pattern, River Power, Kalghan Chai River
  • S. Shayan Pages 133-147
    Introduction
    Iran Country located in arid and semiarid region in terms of quality and quantity Of water and always faced to the problem of shortage of water resources. Khorramabad river is one of the most important rivers and water resources in the Western part of Iran is located in a mountainous region.The River as one of the vital arteries of the city of Khorramabad for managers and planners is very important. Classification is one of simple and applied methods in transfer of knowledge and management tasks. River management plans and engages to natural processes have the most effects on environmental, social and economic conditions. By considering recent year’s flash floods in Khorramabad city which have damages on human beings and properties, and this fact that the river has an important role in supply of water in the region and west part of the country, it is necessary to
    Methodology
    In this study, based on three factors, landscape, pattern river and limitations of river bed of Khorramabad river , we using field observations of the study area, the correction of geometric and mosaic of four sin of satellite images data of Kartosat P5, IRS satellite data by 2.5 resolution of the river basin, we present a classification scheme by a tree stage classification and by using Spss software we have clustering finding and compare it to real states of river by field observations. Classification factors for geomorphic pattern were: landscapes, plan, of river bed and finally limitation of river bed. So landscapes categorized to high mountains, low elevation and plains. In second categorizing we used river pattern as main factor and find tree reaches. Generally, Khorramabad River has 12 segments, include 3 meandering sections, one anastomosing section and 8 straight parts.
    Results And Discussion
    according to our classification method the case study river, Khorramabad by a 64 km length, have 32.72 km of straight section, 25.2 km of meandering pattern, and 1.08 km of anastomosing plan. There was not braided river pattern in the study area. By considering bed confinement ( limitation) , we find 9 segments which segments 2,4,5 and 6 were inside the first class, segments 7,8 and 9 in second class, segment 3 and segment 1 in third and fourth class respectively. The main factor of separation of these segments and making classification was the landscape factor. River pattern was the main factor in the 3rd segment of the river.
    Conclusion
    This classification for rivers can help users and water resources planners and mangers to spend less time and cost for categorizing and managing water resources, but field geomorphic observations and modifying systems results and statistical findings is a main toll that should be used to make a reasonable and reliable classification.
    Keywords: Rivers classification, Fluvial Geomorphology, Environmental Management, Khorramabad River