فهرست مطالب

پژوهش آب ایران - پیاپی 23 (زمستان 1395)
  • پیاپی 23 (زمستان 1395)
  • تاریخ انتشار: 1395/12/13
  • تعداد عناوین: 16
|
  • محمدرضا بازرگان لاری، سحر صفری، اکبر کریمی صفحه 1
    میتواند به عنوان ابزاری کارا در بهره برداری (SVM) استفاده از روش های داده کاوی و به طور خاص ماشین های بردار پشتیبان بهینه از مخازن سدها مطرح شود. نتایج مدل های بهره برداری بهینه از مخازن سدها،‏ به دلیل وجود پارامترها و متغیرهای زیاد،‏ برای کاربرد توسط تصمیم گیران،‏ به واسطه تعامل متغیرها و پیچیدگی آنها،‏ گیجکننده خواهد بود. در این مقاله نتایج یک مدل بهینه سازی به هم پیوسته هیدرولوژیکی- اقتصادی- اجتماعی که برای تخصیص بهینه آب در سطح حوضه آبریز زاینده رود توسعه یافته است،‏ برای تعیین قوانین بهرهبرداری بهینه از سد زایندهرود با ماشین های بردار پشتیبان به کار گرفته شده است. آموزش دیده،‏ با استفاده از شاخص های هیدرولوژیکی و بهرهبرداری بالادست و پایین دست،‏ شامل نیاز آبی،‏ بارش،‏ SVM مدل تقاضاهای آبی شرب،‏ کشاورزی،‏ صنعت و حجم ذخیره اولیه مخزن،‏ میزان رهاسازی بهینه از مخزن سد را در ماه آینده پیشبینی میکند. در ساختار پیشنهادی،‏ از نتایج مدل بهینه تخصیص آب 20 ساله در حوضه آبریز زایندهرود برای آموزش و مقایسه شده است. نتایج آزمون این دو مدل (ANN) استفاده شده است و عملکرد آن با شبکه عصبی مصنوعی SVM آزمون ،‏SVM در مقایسه با ANN نشان میدهد که هر دو در تعیین قوانین بهینه بهرهبرداری از سد زایندهرود کارایی لازم را دارند اما تا حدودی قدرت پیشبینی بهتری دارد.
    کلیدواژگان: مدیریت منابع آب، شبکه های عصبی مصنوعی، بهینهسازی، ماشینهای بردار پشتیبان، سد زایندهرود
  • سعید گوهری صفحه 11
    برخورد دو جریان در رودخانه های طبیعی،‏ کانال های آبیاری و شبکه های آب و فاضلاب مشاهده می شود. در محل برخورد و عوامل (θ) آشفتگی جریان افزایش یافته و جریان سه بعدی حاکم می شود. در این مقاله تاثیر عامل هندسی زاویه تقاطع بر تغییرات تراز سطح آب با استفاده از ،‏(Frd) هیدرولیکی نسبت دبی جریان بالادست به پایین دست و عدد فرود پایین دست مدل هیدرودینامیک سه بعدی فلوئنت بررسی شده است. بررسی ها نشان می دهد که برخورد جریان کانال فرعی و اصلی سبب ایجاد شتاب در جریان اختلاطی شده و با کاهش مقدار نسبت دبی جریان،‏ شتاب جریان نیز افزایش می یابد. افزایش زاویه تقاطع و عدد فرود در پایین دست،‏ مقدار عمق جریان در محل تقاطع را کاهش می دهد. نتایج نشان می دهد که بیشترین مقدار تغییرات سطح آب در زاویه تقاطع 90 درجه و کمترین مقدار در زاویه تقاطع 30 درجه رخ می دهد. با افزایش نسبت دبی مقدار 0،‏ بیشترین / 0 کمترین مقدار و در نسبت دبی 083 / تغییرات سطح آب کاهش یافته و تغییرات سطح آب در نسبت دبی 917 0 اختلاف تراز سطح آب در پایین ترین و بالاترین نقطه / 0،‏ زاویه 90 درجه و نسبت دبی 083 / مقدار بوده است. در عدد فرود 9 به 75 درصد عمق آب در بالادست کانال اصلی می رسد.
    کلیدواژگان: نسبت دبی، مدل عددی فلوئنت، عدد فرود پایین دست، تراز سطح آب، زاویه تقاطع
  • سید میثم مشعشعی، مهدی اسدی آقبلاغی، بهزاد قربانی صفحه 23
    در این پژوهش،‏ اثر تجمع اجسام شناور چوبی روی عمق آبشستگی در اطراف پایه پل ها به صورت آزمایشگاهی بررسی میشود. آزمایش ها در شرایط آب زلال،‏ با شرایط هیدرولیکی متفاوت در فلوم آزمایشگاهی با طول 20 متر و عرض 60 سانتیمتر و ارتفاع 60 سانتیمتر در آزمایشگاه هیدرولیک دانشگاه شهرکرد انجام شد. پایه پل بهصورت مربعی با ضلع 9 سانتیمتر با دماغه تیز مثلثی به ارتفاع 10 سانتیمتر است. اجسام شناور به صورت مستطیلی با طول و عرض متفاوت و در عمق های مختلف نسبت به سطح آب قرار گرفتند. آزمایش ها با دبی های 30 ،‏20 ،‏15 و 40 لیتر بر ثانیه انجام شد. نتایج نشان ،‏1/ داد که وقتی اجسام شناور بالای سطح آب،‏ هم سطح آب و زیر سطح آب باشند عمق آبشستگی،‏ به ترتیب،‏ حداکثر تا 7 2 برابر نسبت به نمونه شاهد افزایش می یابد. علاوه بر این،‏ زمانی که درصد انسداد (نسبت مساحت اشغال شده / 1 و 2 /85 جریان با اجسام شناور به سطح مقطع جریان) برابر با % 30 و اجسام شناور در زیر سطح آب قرار گرفته باشند،‏ بیشینه عمق 2 برابر نمونه شاهد) رخ میدهد. همچنین معادل های برای محاسبه حداکثر عمق آبشستگی در حضور تجمع / آبشستگی ( 2 اجسام شناور چوبی در جلو پایه مربعی با دماغه تیز ارائه شد.
    کلیدواژگان: تجمع اجسام شناور، آبشستگی، پایه پل، مدل آزمایشگاهی
  • رامین منصوری، علی ضیایی صفحه 33
    در این پژوهش خصوصیات هیدرولیکی در شیبشکنهای قائم با پایاب متفاوت در پاییندست (شیبشکن قائم ساده،‏ شیبشکن قائم با شیب معکوس کف در پایاب و شیبشکن قائم با آستانه انتهایی) بهصورت عددی بررسی شده است. خصوصیات جریان از جمله اعماق جریان در محلهای مختلف،‏ افت انرژی،‏ پروفیل سطح آب و پروفیل سرعت،‏ توزیع فشار و تنش برشی در بستر حوضچه بهصورت عددی مدل و با نتایج آزمایشگاهی مقایسه شد. نتایج عددی در شرایط،‏ شبکه استاندارد و تابع دیواره استاندارد بهترین نتایج را برای مدلسازی k-e محاسباتی شامل 57512 گره،‏ مدل آشفته دو معادلهای جریان آب در شیبشکنها ارائه میدهد. افت انرژی در شیبشکن قائم با آستانه انتهایی بیشترین مقدار را داشته و کمترین مقدار افت انرژی مربوط به شیبشکن قائم ساده به دست آمد. خصوصیات سرعت در حوضچه،‏ تیغهی ریزشی و لغزشی جریان با خصوصیات سرعت اندازهگیری شده در این نواحی همخوانی بسیار خوبی دارد. (falling and sliding jet)
    کلیدواژگان: شیبشکن قائم، خصوصیات سرعت، پروفیل سطح آزاد آب، مدل آشفته، افت انرژی
  • شایان شامحمدی صفحه 45
    یکی از مهمترین اهداف مطالعات جذب در محلولهای آبی،‏ تعیین حداکثر ظرفیت جذب است. در طی 100 سال گذشته،‏ مدلهای زیادی در این زمینه ارائه شده است،‏ ولی بجز مدل ایزوترم لانگمویر و تا اندازهای مدل برونر و همکاران،‏ هیچکدام از مدلها از تئوری ریاضی مهمی برخوردار نیستند. در این پژوهش،‏ با مروری بر نظریه لانگمویر،‏ تئوری مدل مورد نقد قرار میگیرد. اگرچه شکل کلی مدل توجیه کننده رفتار جذب تعادلی میباشد،‏ ولی در این پژوهش،‏ نشان داده می شود که نمیتوان از اصل لوشاتلیه نتیجه گرفت که سرعت جذب و سرعت واجذب با هم برابرند. همچنین مرور بر روش های آزمایش ایزوترم جذب نشان میدهد که اصولا تغییرات زمانی وجود ندارد و در نتیجه استفاده از مفاهیم سرعت صحیح نمیباشد. همچنین استفاده از تساوی سرعت جذب و واجذب با قانون بقای جرم مغایرت دارد. بنابراین،‏ تئوری مدل لانگمویر مبتنی بر فرضیات غیرواقعی بوده و فاقد اعتبار نظری است.
    کلیدواژگان: سرعت جذب و واجذب، مدل لانگمویر، فرضیات، مدلهای ایزوترم
  • احمد احمدی نیک، علی رحیمی خوب صفحه 53
    سیستم آبیاری تراکمی،‏ از ایده های نوین در زمینه تامین آب شیرین است. اهمیت این ایده از لحاظ تامین آب شیرین در شرایط بحرانی،‏ استفاده از انرژی خورشیدی در تصفیه آب شور،‏ کاهش هزینه های تامین و انتقال آب و در نظر داشتن مسایل زیست محیطی در قالب کنترل آلودگی منابع آب شیرین موجود،‏ نشان دهنده لزوم مطالعات گسترده در این زمینه است. از آنجا که هدف نهایی یک سیستم آبیاری با هر نوع روش و عملیاتی،‏ تامین نیاز آبی گیاه است بنابراین ارزیابی میزان آب قابل تامین با هر سیستم آبیاری با نیاز آبی گیاه امری ضروری و معیاری جهت پذیرش یا نپذیرفتن سیستم پیشنهاد شده است. مخزن خورشیدی اصلی ترین جزء سیستم تراکمی است که نقش تامین آب شیرین را بر عهده دارد؛ لذا در این مطالعه پتانسیل تبخیر مخازن خورشیدی و نیاز آبی گیاه ذرت دانه ای در مراحل مختلف رشد مقایسه شد. نتایج حاکی از آن بود که میزان تبخیر از مخزن خورشیدی در تمامی دوره های رشد از نیاز آبی گیاه بیشتر است و در برخی مراحل رشد،‏ یک مترمربع از مخزن خورشیدی قادر به تامین نیاز آبی حدود سه مترمربع از گیاه ذرت دانه ای است. با توجه به کارآیی سیستم آبیاری تراکمی در کاربرد آب شور،‏ پتانسیل مخازن خورشیدی قابل توجه بوده است و لزوم مطالعات گسترده در زمینه ارتقاء پتانسیل تبخیری این مخازن را نمایان می کند.
    کلیدواژگان: تبخیر و تعرق، نمک زدایی، انرژی خورشیدی، سیستم آبیاری تراکمی، آب شور
  • فرخنده سادات هاشمی مدنی، محمد ابراهیم بنی حبیب صفحه 63
    در پژوهش حاضر،‏ برای تعیین راهبرد درازمدت مدیریت منابع آب در مناطق خشک بر اساس معیارهای توسعه پایدار،‏ از استفاده (AHP) و تحلیل سلسله مراتبی (SAW) ترکیب روش بارش فکری با مدلهای تصمیمگیری چندمعیاره وزندهی ساده شده است. ابتدا با استفاده از روش بارش فکری،‏ 9 گزینه مختلف برای مدیریت راهبردی منابع آب در استان شاهرود در نظر و راهبرد نظارت در بهرهبرداری از آبخوانها SAW گرفته و مشاهده شد راهبرد تدوین و اجرای طرح آمایش سرزمین در مدل رتبه های اول را به خود اختصاص دادند. همچنین بر اساس حداقل نمره قبولی هر راهبرد برای رعایت AHP در در مدل مطابق با اصول توسعه پایدار شناخته AHP معیارهای توسعه پایدار( 50 % وزن معیارها)،‏ راهبرد انتقال آب بینحوضهای با مدل ±% نشد و اجرای این راهبرد از لحاظ توسعه پایدار توصیه نگردید. علاوه براین،‏ تحلیل حساسیت این مدلها در سطوح 20 تغییر در وزن هر یک از معیارها صورت گرفت و مشاهده شد که این روش ها نسبت به معیارهای مقبولیت و مشارکت اجتماعی فرهنگی ذینفعان و حفاظت از منابع طبیعی و تعادل زیستمحیطی که وزن بالایی در میان سایر معیارها دارند،‏ حساسیت نسبت به تغییرات در وزن معیارها نسبت به AHP بیشتری نشان داده و ندی متفاوتی را ارائه میدهند. همچنین مدل تعیین راهبرد درازمدت ،‏SAW حساسیت کمتری نشان میدهند و با توجه به تفاوت قابل اغماض نسبت به مدل SAW مدل مدیریت منابع آب با این مدل توصیه شد.
    کلیدواژگان: تحلیل سلسله مراتبی، وزندهی ساده، توسعه پایدار، مدیریت راهبردی منابع آب، تصمیمگیری چندمعیاره
  • رضا هزاره، یوسف حسنی، سمیراشایان مهر صفحه 73
    آب مهمترین و محدودکنندهترین نهاده تولید در کشاورزی ایران است. به دلیل محدودیت عرضهی آب و هزینه های هنگفت تامین آن،‏ بهبود شاخصهای بهرهوری را از مهمترین عوامل مدیریت بخش تقاضای آب به یک ضرورت حتمی و حیاتی در مدیریت منابع آب تبدیل کرده است. در بسیاری از نقاط توسعهیافته و درحال توسعه جهان برای مقابله با کاهش شدید و فزاینده منابع آب و تنشهای وارده بر آن،‏ از ابزارهای گوناگون سیاستهای مدیریت منابع آب استفاده می شود بر این اساس،‏ در این مطالعه سیاستهای مختلف مدیریتی منابع آب را در طی شش سناریوی قیمتگذاری،‏ مالیات برنهاده و مالیات بر محصول ارزیابی شد و آثار هر یک از این سناریوهای سیاستی را بر شاخصهای بهرهوری اقتصادی،‏ مالی و اشتغال بررسی 1390 در دشت قزوین بهره - گردید. در این پژوهش از روش برنامه ریاضی مثبت و حداکثر بینظمی در سال زراعی 1391 گرفته شد. نتایج نشان داد اعمال سیاستهای مدیریت منابع آب علاوه بر اینکه باعث کاهش مصرف آب میگردد،‏ آثار نامطلوب اقتصادی و اجتماعی خواهد داشت که میبایست در اعمال این سیاستها به این جوانب نیز توجه شود. نتایج سه شاخص بهرهوری در این پژوهش،‏ نشان داد که سیاست ترکیبی قیمتگذاری آب (افزایش 25 درصدی قیمت آب) و کاهش آب در دسترس ( 20 درصد) بهترین وضعیت را در شاخصهای بهرهوری منطقه ایجاد میکند.
    کلیدواژگان: حداکثر بی نظمی، قزوین، بهره وری آب، قیمت گذاری آب
  • سهیلا زارعی، احمد فاخری فرد، اسماعیل اسدی صفحه 85
    هدف در پژوهش حاضر،‏ تعیین شاخص آماری تلفیقی بر مبنای خشکسالی هواشناسی و هیدرولوژیکی در مقیاس منطقهای است. داده های بارش با استفاده از روش چند ضلعی تیسن به بارشهای ناحی های تبدیل شد. با استفاده از رژیم نرمال،‏ مقدار دوره های خشک هم برای جریان و هم برای بارش استخراج و تبدیل به مقدار کمبود حجم شدند. تحلیل فراوانی دوره های کمبود با استفاده از روش های توزیع آماری،‏ انجام پذیرفت. نتایج نشان داد که توزیع نرمال،‏ با کمترین مقدار مجذور مربعات ،‏1/924 ،‏1/917 ،‏2/043 ،‏1/950 ،‏1/ خطا برای کمبود دوره های خشکی بارش برای تداومهای یک تا نه ماهه به ترتیب ( 074 ،‏3/508 ،‏3/101 ،‏2/663 ،‏2 ،‏1/ 5) و توزیع پیرسون تیپ 3 برای کمبود حجمهای جریان ( 179 /489 ، 3/515 ،‏2/641 ،‏1/981 5) بهترین توزیع بودند. با استفاده از توزیعهای آماری حاصله،‏ منحنی های کمبود حجم- مدت- /029 ، 4/828 ،‏4/321 ،‏3/812 فراوانی استخراج و برای هر یک از آنها معادلات ریاضی مناسب بر اساس ضریب همبستگی و کمترین مقدار خطا استخراج گردید. سپس در انتها ارتباط بین هر دو خشکسالی هواشناسی و هیدرولوژیکی به صورت مستقل از زمان و مبتنی بر دوره بازگشت در قالب یک شاخص آماری نمایی تعیین گردید.
    کلیدواژگان: شاخص آماری تلفیقی، خشکسالی، تحلیل فراوانی، حوضه صوفیچای
  • رزگار عرب زاده، شهاب عراقی نژاد، مسعود امیرخانی، آرام جلالی بوربان صفحه 93
    امروزه مطالعه روی سامانه های آب زیرزمینی و ارائه روش های جدید و ابزارهای مدیریتی،‏ به فعالیت گسترده در میان مدیران و برنامه ریزان منابع آب تبدیل شده است. از آن جایی که بخش عمدهای از آبهای مورد استفاده درایران از منابع زیرزمینی و آبخوان تامین می شود،‏ اطلاع از ویژگی های کمی و کیفی آب از این نوع سامانه های منابع آب میتواند نقش راهبردی و تعیین کننده ای در برنامه ریزی منطقه داشته باشد. با توجه به اهمیت این موضوع در این مقاله از یک مدل شناخته شده آسیب پذیری آب زیرزمینی برای ارزیابی آسیب پذیری آبخوان در حالت وجود یک آلاینده استفاده میشود. برای ارزیابی نتایج نیز از ضریب همبستگی اسپیرمن بهره گرفته شد. نتایج نشان داد همبستگی بین شاخص آسیب پذیری آب زیرزمینی و غلظت و با در نظر گرفتن ضریب (GRG 0 است. سپس پارامترهای مدل با استفاده از الگوریتم ( 2 / برابر با 493 (NO نیترات ( 3 0/ همبستگی به عنوان تابع هدف بهینه سازی شد. نتایج به دست آمده بعد از بهینه سازی نشان داد که همبستگی تا مقدار 651 افزایش یافته است. در نهایت میتوان نتیجه گرفت که از روش مورد استفاده در این پژوهش میتوان به عنوان یک مدل دقیق برای تعیین آسیب پذیری آبخوان های مختلف استفاده کرد.
    کلیدواژگان: آسیب پذیری، GRG2، دهگلان، آبخوان، DRASTIC
  • حسام سیدکابلی صفحه 101
    در حال حاضر در ایران،‏ حجم قابل توجهی از آب ذخیره شده در سدها تبخیر میشود. از طرفی،‏ تغییراقلیم ناشی از فعالیت های بشری روند تغییرات حجم تبخیری را نیز دستخوش دگرگونی کرده است. این پژوهش تحلیلی از روند تغییر حجم 2051 در شرایط تغییر اقلیم مدل شده با پنج مدل اقلیم جهانی - 2021 و 2080 - تبخیری از سد دز را برای دو دوره 2050 ارائه کرده است. داده های هواشناسی روزانه با مدل ریزمقیاس نزدیکترین همسایگی ارتقاء داده شده A تحت سناریوی انتشار 2 جهت برآورد نرخ تبخیر از سطوح آزاد آب با استفاده از معالات مشتق شده از معادله پنمن آماده سازی شدند. تغییرات حجم 1982 محاسبه شدند. نتایج نشان - تبخیری با به کاربردن روابط حجم- ارتفاع مخزن سد دز نسبت به دوره مشاهداتی 2011می دهند حجم تبخیر سالانه از این مخزن،‏ به طور متوسط برای هر دو دوره مورد بررسی،‏ به ترتیب % و 10 % افزایش می یابد. عامل اصلی در پشت این افزایش،‏ گرمایش زمین در آینده است؛ به گونه ای که متوسط دمای هوا در دو دوره آتی به طور 1 و 3 درجه سانتیگراد نسبت به دوره پایه افزایش پیدا خواهد کرد. این افزایش تاثیر معنی داری در نرخ / میانگین به ترتیب 3 تبخیر دارد،‏ به ویژه در فصل های بهار و تابستان که دمای هوا به طور چشمگیری زیاد خواهد شد.
    کلیدواژگان: معادله پنمن، سناریوی انتشار، ریزمقیاس کردن، مخزن سد، GCMs، تغییرات آب و هوایی
  • عطا الله ندیری، جمیل روزرخ، اصغر اصغری مقدم صفحه 111
    در این پژوهش،‏ هیدروژئولوژی و فرآیندهای هیدروژئوشیمیایی منابع آب زیرزمینی آبخوان دشت هرزندات بررسی شده است. در دهه های اخیر،‏ سطح آب زیرزمینی این آبخوان،‏ به شدت کاهش یافته که این امر،‏ باعث کاهش کیفیت آب زیرزمینی شده است. برای درک بهتری از فرآیندهای هیدروژئوشیمیایی دشت هرزندات،‏ 77 نمونه آب زیرزمینی جمع آوری شده به روش های گرافیکی و تکنیک های آماری چندمتغیره تجزیه و تحلیل شده است. نتایج دیاگرام پایپر نشان می دهد که دو تیپ آب و دیاگرام استیف نشان دهنده شش منشا متفاوت برای نمونه های آب زیرزمینی است. دیاگرام دورو نشان دهنده دو فرآیند هیدروژئوشیمیایی اصلی در آبخوان است؛ در صورتی که روش آنالیز خوشه ایسلسله مراتبی نشان می دهد که پنج تیپ آبی در نمونه های آب زیرزمینی وجود دارد؛ زیرا تکنیک آنالیز خوشه ایمرتبه ای در مقایسه با روش های گرافیکی،‏ توانایی آنالیز شیمیایی و فیزیکی برای داده های بیشتری را دارد. بر اساس روش تحلیل عاملی،‏ چهار عامل اصلی موثر بر هیدروشیمی آبخوان دشت هرزندات شناسایی شد. عامل های اول،‏ دوم و سوم تاثیر سازندهای زمین شناسی و روند تکاملی جریان آب زیرزمینی را نشان می دهند و عامل چهارم متاثر از فعالیت های انسانی است. در عامل نخست کلر،‏ سولفات،‏ منیزیم،‏ کلسیم و هدایت الکتریکی،‏ در عامل دوم سدیم،‏ درصد سدیم و نسبت جذب سدیم و در مولفه سوم بی کربنات و پتاسیم موثر هستند،‏ در حالیکه در مولفه چهارم،‏ کربنات با نیترات و اسیدیته مرتبط بودند.
    کلیدواژگان: روش گرافیکی، دشت هرزندات، هیدروژئوشیمی، آنالیز آماری چندمتغیره
  • مهرداد تقیان صفحه 123
    در سال های اخیر،‏ دیدگاه جامع نگر و مدیریت یکپارچه،‏ جایگزین دیدگاه سنتی و بخشی نگر در طرح های توسعه منابع آب شده است. در این راستا،‏ یکی از پارامترهای موثر بر عملکرد سیستم،‏ رتبه بندی بهره برداری از مخازن در تامین نیازهای مشترک پایاب است. در حقیقت،‏ ترتیب پر و خالی شدن مخازن که به صورت سری یا موازی قرار گرفته اند،‏ بر نحوه توزیع ظرفیت خالی ذخیره در بین مخازن موثر است و از آنجا،‏ بر مجموع تلفات ناشی از سرریز و تبخیر و در نهایت مجموع آب تنظیمی از سدهای مخزنی اثر مستقیم دارد. در این مقاله،‏ از یک مدل شبیه سازیشبکه جریان با موتور بهینه سازی برنامه ریزی خطی برای رتبه بندی بهره برداری از مخازن در یک دوره درازمدت آبدهی ماهانه استفاده شده است. به عنوان مطالعه موردی،‏ سیستم هفت مخزنی منابع آب زهره در جنوب غربی کشور بررسی شده است و گزینه های مختلفی برای رتبه بندی بهره برداری از سدهای مخزنی تعریف شده است که حدود 6 درصد بر کاهش تلفات سیستم شامل سرریز و تبخیر از سطح مخزن موثر بوده است. در این حالت،‏ کاهش تلفات مربوط به سرریز از سیستم منابع آب نقش موثرتری در مقایسه با تبخیر ایفا کرده است. همچنین بر اساس گزینه برتر رتبهبندی مخازن در مقایسه با گزینه پایه (اولویت یکسان)،‏ شاخص اعتمادپذیری و آسیب پذیری بهبود یافته است؛ اما شاخص سرعت برگشت پذیری اندکی افت داشته است و آثار رتبه بندی سدهای موازی،‏ موثرتر از آثار رتبه بندی سدهای سری بوده است.
    کلیدواژگان: رتبه بندی مخازن، حوضه زهره، بهینه سازی، شبیه سازی، برنامه ریزی خطی
  • فرزام حسن نژاد شریفی، امیر صمدی، اصغر عزیزیان صفحه 133
    اطلاعاتی که از منحنی دانه بندی ذرات بستر استخراج می شود،‏ کاربردهای فراوانی در زمینه مهندسی رودخانه مانند مدل سازی انتقال رسوبات،‏ تغییر وضعیت رسوبگ ذاری یا فرسایش بستر رودخانه و تغییرات ریخت شناسی رودخانه دارد. در این پژوهش در بازه معینی از مسیر رودخانه شلمان رود (واقع در استان گیلان) برای دستیابی به منحنی های دانه بندی رسوبات سطحی بستر به دو روش دانه بندی با الک و پردازش تصاویر،‏ در 25 نقطه معین واقع در راستای طولی بستر رودخانه،‏ ضمن تهیه تصاویر دیجیتالی از فراز رسوبات با استفاده از دوربین 10 مگاپیکسلی،‏ نمونه برداری سطحی از مصالح رسوبی انجام شد. برای سنجش حساسیت روش پردازش تصویر به اندازه سطح رسوبی مورد پردازش،‏ از دو قاب چوبی در ابعاد 40 در 40 سانتی متر و 70 در استفاده گردید. نتایج FHWA Hydraulic Toolbox 70 سانتی متر استفاده شد. همچنین برای پردازش تصاویر از نرم افزار 4.2 تحلیل های آماری انجام شده بین منحنی های حاصل از دو روش (آزمایشگاهی و نرم افزاری) نشان داد که روش پردازش تصاویر با استفاده از برنامه مذکور از دقت بسیار زیادی در برآورد منحنی دانه بندی ذرات رسوبی برخوردار است. همچنین این روش در حالتی که سطح مورد پردازش در تصاویر ورودی به نرم افزار،‏ کوچک تر انتخاب شود و ذرات به مرکز تصویر نزدیک تر باشد،‏ از دقت بیشتری برخوردار است.
    کلیدواژگان: FHWA Hydraulic رسوبات سطحی بستر، نرم افزار، منحنی دانه بندی، دانه بندی با الک، پردازش تصاویر
  • مهدی خالقی، حسین زینی وند، علی حقی زاده صفحه 143
    در شبیه سازی رواناب روزانه،‏ تحلیل حساسیت پارامترهای مدل و تاثیر آن بر مولفه های WetSpa در این پژوهش،‏ کارایی مدل مختلف چرخه هیدرولوژیکی حوزه آبخیز رودخانه خرمآباد در استان لرستان مورد بررسی قرار گرفته است. برای این منظور از برای واسنجی،‏ تحلیل حساسیت و آنالیز عدم قطعیت بهره PEST برای شبیه سازی و از نرم افزار WetSpa مدل توزیعی- مکانی گرفته شد. آمار مشاهداتی دبی روزانه ایستگاه هیدرومتری دوآب ویسیان خرمآباد،‏ به عنوان ایستگاه مبنا طی سال های 1383 تا 1389 برای واسنجی و اعتبارسنجی نتایج مدل مورد استفاده قرار گرفت. بعد از فرآیند واسنجی،‏ مولفه های مختلف چرخه به عنوان Krun پارامتر ،‏PEST هیدرولوژیکی استخراج و مورد بررسی قرار گرفت. در تحلیل حساسیت پارامترها با روش حساس ترین پارامتر شناخته شد. ارزیابی کارایی مدل با استفاده از شاخص های آماری از جملهمعیار نش- ساتکلیف (برای 66 درصد)،‏ نشان داد که این مدل قابلیت بالایی در شبیه سازی رواناب / 83 و 44 / مرحله واسنجی و اعتبارسنجی به ترتیب با 76 میتواند به عنوان ابزاری مهم برای شبیه سازی رواناب،‏ فهم بهتر فرآیندهای مختلف WetSpa روزانه دارد. بنابراین مدل هیدرولوژیکی حوزه،‏ مدیریت و ارزیابی بهینه منابع آبی در دوره زمانی روزانه مورد استفاده قرار گیرد.
    کلیدواژگان: مدلPEST، رودخانه خرم آباد، تحلیل حساسیت، WetSpa، دبی روزانه
  • محمدرضا پورطبری محمود، شیوا توکلی، امیر شالچی تبریزی صفحه 149
    سرریزهای استوانه ای از جمله سرریزهای لبه پهن هستند که نسبت به موارد جایگزین دارای مزایایی از جمله اقتصادی،‏ طراحی آسان و ضریب دبی بالا است. انحنای زیاد خطوط جریان روی این نوع سرریزها از عوامل موثر بر ضریب دبی است. بررسی ضریب دبی جریان در سرریزهای استوانه ای به دلیل تغییرات شرایط هیدرولیکی آنها در طراحی و کاربرد این سازه ها مهم 11 سانتیمتر با استفاده از مدل عددی /4 ،‏9 ،‏6/ است. در این پژوهش جریان روی سه گروه سرریز استوانه ای با قطرهای 3 مورد بررسی شده است. در این بررسی برای حل معادلات حاکم از روش حجم محدود و برای ارزیابیآشفتگی FLOW-3D استفاده شده است. نتایج این پژوهش به صورت پروفیل های سرعت ارائه شده و ضریب دبی جریان برای RNG جریان از مدل دبیه ای متفاوت محاسبه شد. نتایج به دست آمده از این مدل عددی با نتایج آزمایشگاهی همین گروه سرریزهای استوانه ای مقایسه و مشخص شد که همخوانی خوبی دارد.
    کلیدواژگان: حجم محدود، ضریب دبی، Flow، 3D، سرریز، مدل عددی
|
  • Bazargan-Lari_Mohammad Reza - Safari_Sahar - Karimi_Akbar Page 1
    Optimal reservoir operation is generally a complex problem due to the wide range of important influencing factors. Crop mix pattern optimization and limitations, economic indices of agriculture, industry and water supplier and reservoir operation requirements are examples of the factors that might be taken into account in developing a comprehensive optimal model for reservoir operation. The considerable number of involved variables and parameters as well as their complex interactions increase the complexity of the problem and therefore poses limitations for real-time applications. The management process can be simplified for real-time applications using accurate data mining models. While the reservoir optimum operation model is available a large set of data can be generated with different data sets to represent a wide range of conditions which reservoir may operate under it, including the best decisions for water release and storage. Support Vector Machine (SVM) is a relatively new and promising supervised machine learning technique based on the statistical learning theory which is receiving increasing attention lately in the field of water resources management. The combination of SVM , as a well-known data mining method in acquiring complex patterns of behavior and complexity of real reservoir operation models, and a real reservoir operation model seems promising in presenting a simplified model for reservoir operation while considering a large amount of parameters affecting the reservoir operation.
    Herein, a complex reservoir operation model for Zayandehrood dam considering upstream and downstream rainfall-runoff, groundwater supply, crop mix, income and employment in agriculture and industry sectors, water demand of domestic, agriculture and industry sectors and interactions of these different factors is utilized to produce a large set of hydrologic, socio-economic and reservoir operation data based on a long-term optimization approach. In this paper, results of a developed integrated hydrologic-socio-economic optimum water allocation model in the Zayandehrood water basin are used by SVM to derive the optimum operating rules for the Zayandehrood dam. The trained SVM predicts the optimum water release from Zayandehrood reservoir based on upstream and downstream hydrologic and operational indices including monthly precipitation, reservoir initial storage, irrigation, industry and domestic water demands. Zayandehrood reservoir operation model produces the optimal crop mix pattern and level of industry production considering the net profit and employment indices as well as the water authority and domestic water supply profits at upstream and downstream of the Zayandehrood dam's reservoir. Considering this optimal set of the data, optimal value of the water demand according to each set of reservoir storage state and precipitation is determined. The reservoir initial storage volume, upstream and downstream precipitation are then used as inputs to produce the optimal water allocation and reservoir release which are automatically producing the optimal net profit and employment in agriculture, industry, water supply and water authority sectors. Therefore, here optimal reservoir operation data sets are produced that are hydrologically and socio-economically optimal for a long period of 20 years. These data sets contain optimal management decisions of the Zayandehrood dam's reservoir system within the Zayandehrood water basin.
    SVM is trained and tested by randomly splitting the 20 year's monthly data analysis results (240 data point for each parameter). The train and test data sets were normalized in the range of 0 to 1 and learning parameters were chosen through an optimization procedure. Considering the fact that choosing the most appropriate kernel is depends on the problem being considered, the key stage in SVM is choosing the appropriate kernel function. Linear, Polynomial, Gaussian and Hyperbolic kernels are the most popular kernel functions that are used in this work. Root Mean Square Error (RMSE) and Correlation Coefficients (CC) are the statistical measures used for choosing the best Kernel function in a trial-error procedure. Results of water allocation model in Zayandehrood water basin and the performance of the trained SVM are compared with Artificial Neural Network (ANN) which is a well-known classical machine learning algorithm. The performance of SVM-based and ANN-based predictions is evaluated and the normality of errors is studied as well. The test results show that the errors are independent and are normally distributed and both models are efficient in determining the rules for optimal reservoir operation. However, the ANN-based predictions had somewhat higher predictive power than the SVM-based predictions.
    Optimal reservoir operation is generally a complex problem due to the wide range of important influencing factors. Crop mix pattern optimization and limitations, economic indices of agriculture, industry and water supplier and reservoir operation requirements are examples of the factors that might be taken into account in developing a comprehensive optimal model for reservoir operation. The considerable number of involved variables and parameters as well as their complex interactions increase the complexity of the problem and therefore poses limitations for real-time applications. The management process can be simplified for real-time applications using accurate data mining models. While the reservoir optimum operation model is available a large set of data can be generated with different data sets to represent a wide range of conditions which reservoir may operate under it, including the best decisions for water release and storage. Support Vector Machine (SVM) is a relatively new and promising supervised machine learning technique based on the statistical learning theory which is receiving increasing attention lately in the field of water resources management. The combination of SVM , as a well-known data mining method in acquiring complex patterns of behavior and complexity of real reservoir operation models, and a real reservoir operation model seems promising in presenting a simplified model for reservoir operation while considering a large amount of parameters affecting the reservoir operation
    Keywords: Water resources management, Artificial neural networks, Zayandehrood dam, Support vector machines, Optimization
  • Gohari, Saeed Page 11
    Intersection of two flows have always been a great challenge to hydraulicians in natural or artificial channels. River channel confluences are critical interfaces where intense changesin physical processes occur. These changes affect both the local and downstream characteristics of the river flow and of the bed. There are many parameters affecting on flow patterns in this matter which cause flow complexity. These factors are relevant to not only geometry parameters like cross section, dimension, slope or angle between two channels but also hydraulic parameters like Froude number and discharge ratio in two channels. In addition to mentioned parameters, mobile bed in the form of bed load and suspended load has a major influence on flow pattern in which change geometry and hydraulic design parameters. According to water surface level as an important factor in flow intersections which has not investigated well in previous researches, so the simultaneous effects of geometry and hydraulic parameters on flow pattern and water level variations are discussed in this study. This research was based on numerical study with Fluent model. Geometry creation and meshing were done by Gambit software. Gambit provides a concise and powerful set of solid modeling-based geometry tools. Existing data in hydraulic research center in Iowa University used to validate numerical results. The Reynolds Averaged Navier-Stokes (RANS) turbulence model is used to simulate the turbulent flow field. According to using Volume of Fluid (VOF) method for simulating two-phase flow, the water phase is considered as stable fixed water column in the inlet of the model. Other internal volume of the geometry (10 centimeters above the initial water level) is filled with air. In the inlet of flow field, uniform velocity boundary condition based on experimental condition for water phase and the same velocity boundary condition with trivial velocity value (0.00001 m/s) for air phase are considered. Also, zero-gradient boundary condition is used for pressure in the outlet and wall condition with no slope is considered for channel sides. Finally, symmetric boundary condition is considered to introduce surface flow. Average and maximum error of simulating water surface level in 90 degree confluence was 1% and 3% respectively. Also maximum reduction in water surface level was occurred at lower discharge ratio and by increasing discharge ratio water surface oscillation was decreased . The results showed that with increasing discharge ratio, secondary channel impact will be less on total flow. When secondary channel flow collides to opposite bank of main channel flow at 90 degrees; two flows join together making accelerated flow moves downstream. It can be seen vortex flow after collision of two flows due to high velocity of fluid upper layers. Turbulence and flow mixing will decrease by reducing angle of two flows intersection and flow moves downstream with less energy dissipation causing a reduction in the upstream depth to downstream. The region of flow near the upstream junction corner can be characterized by a zone of relatively slow-moving fluid, with slight water surface super- 1 - Assistant professor of Department of Water Engineering, Bu Ali Sina University, Hamadan, Iran. elevation, that is generated by the stagnation of flow in this region. Flow within this stagnation zone can be recirculating, or exhibit reverse flow from one tributary into the other. Also, increasing the Froude number would strengthen accelerating flow in two channels making mixed flow with less depth and high velocity toward downstream. The effects of angle of intersection, Froude number and discharge ratio on water level variation have been investigated in rectangular channel intersection. The results showed all three mentioned parameters play an important role in flow pattern. Comparison of experimental and numerical results showed model can simulate water level variations very well in channels intersection. The effects of angle of intersection will reduce with increasing in discharge ratio until disregard at a 0.917 ratio. The main result of the study has showed the flow will accelerate quickly with increasing angle of intersection and making vortex with change in flow direction due to collision of two flows. The most important factor was discharge ratio effecting on water level variation trend where Froude number in downstream and angle of intersection stood at the nest place respectively. The highest and lowest changes in the relative depth is observed in the intersection angle of 90 and 30 degrees respectively. Froude number has important role in changing of relative depth so that at intersection angle of 90 degree, the discharge ratio of 0.083 and Froude number 0.9 the depth ratio is reached to 1.76. Investigation of above parameters would be necessary due to water level variation and making bed forms in mobile bed. Also the knowledge of their mechanism can be helpful effectively to
    Keywords: Downstream Froude number, water level, Discharge ratio, Fluent model, Junction angle
  • Moshashaie, Seyed Meysam, Asadi-Aghbolaghi, Mahdi, Ghorbani, Behzad Page 23
    Trees are destroyed by natural phenomena such as landslide, wind or flood, … and are floated in flow direction on the river surface. Floating debris accumulates in front of hydraulic structures, such as bridges, and increases the flow velocity as a result of decreasing the flow cross section. Consequently, both scour around the bridge pier and hydraulic forces acting on the bridge pier are increased. So the floating debris may have catastrophic effect on the bridge. The recognition of flow field around bridge piers may be useful to prevent the damages on these structures. Researches showed that horse shoe vortexes are formed in front of pier and waking vortexes are formed in the back of pier. In addition, in front of the bridge pier downward flow has an important role on the scour depth, the woody debris will intensify the downward flow and therefore the scour depth is significantly increased.
    In this study, the effect of woody debris accumulation on the scour depth in correspondence of the bridge piers is experimentally investigated. The experiments were performed in clear water condition as well as different hydraulic conditions in an experimental flume with a 20 m length, 60 cm width and 60 cm height in hydraulic lab of Shahrekord University. Bridge pier was a sharp nose square pier which comprises a square with a 9 cm side length and a sharp triangular nose with a 10 cm height. The nose of the triangle was a 48-degree angle. Rectangular woody debris with different lengths and widths is used for the experiments. These woody debris are located in front of bridge pier and in different depths with respect to the water surface. The experiments were performed with 15, 20, 30 and 40 l/s flow rates. All the experiments were performed at a 20 cm flow depth. The average size of sand particles was d50=0.78 mm, and in all experiments the flume slope was 0.001. The scour depth was measured by a caliper with 0.1 mm accuracy. The scour depths are read at time = 1, 15, 20, 30, 45, 60, …, 420 minute. The results showed that the maximum scour depth occurs at t=7 hour.
    In order to perform the clear water condition, in which there should be no sediment transport in the flume except around pier, the threshold of sediment incipient motion must be determined. Therefore, the incipient motion particles velocity, Uc, based on Richardson and Davis's equation is estimated (Uc = 0.388 m/s). In all experiments the flow velocity was greater than Uc. In each experiment, the flume bed was balanced. After fixing the woody debris in front of the pier, the flume was filled with water at a low flow rate (Q  0.001 m3/s) and then the flow rate was increased to reach desired discharge value. Dimensionless parameters are determined using dimensional analysis.
    The results showed that woody debris has a significant effect on the scour depth and the position of the woody debris is also effective on the scour depth. When the woody debris is placed over the surface, at the surface, and below the surface, respectively, the ratio of scour depth to the scour depth of control sample is 1.7, 1.85 and 2.2. Moreover, when the percentage of blockage (ratio of the area occupied by floating objects to the flow cross section) is 30% and debris is located below the water surface, the maximum depth of scour (2.2 vs. control sample) will occur. Furthermore, the scour hole profile around bridge pier was measured and plotted, the results showed that the woody debris dimensions has significant effect on the width and length of the scour hole. The effect of roughness was also investigated, and the results showed that the roughness does not affect the scour hole dimensions, but can increase the dynamic force acting on the pier. The results of dimensional analysis were used in order to find an equation for predicting the maximum scour depth in present of woody debris accumulation. The parameters that have less effect on the scour were not considered in the regression. An equation was presented for calculating the maximum scour depth around a sharp nose pier in presence of woody debris accumulation. The predicted results have good agreement with the measured one.
    Keywords: Bridge pier, Debris accumulation, Scour, Experimental model
  • Mansouri, Ramin, Ziaei, Ali N Page 33
    Drops are hydraulic structures that are commonly used in irrigation and waste water collection networks. A vertical drop balances the elevational variation between the channel slope and ground slope. Thus the flow structure is comprised of a falling jet (free overfall), a sliding or skimming jet and a circulating or mixing zone. This pattern causes the significant portion of flow energy to be dissipated through jet impact and turbulent mixing. In this study the complex flow pattern in the vertical drop with different forms of downstream channel was studied numerically. The two dimensional RANS equations accompanied with volume of fluid (VOF) method are applied. The results of the simulation are then compared to the experimental results. The details of energy loss and velocity profiles in different locations are also scrutinized.
    In this study three different data sets were used. The first data set presented (case A) was measured by Lin et al. (2007). Their experiments were conducted in a flume of 8.85 m length with a glass-walled and glass-bottomed test section of 3.05 m length, 0.50 m width and 0.54 m depth. Two vertical drops with heights of 11.0 and 20.0 cm were chosen. Another set of data (case B) were collected by Chamani et al. (2005) in a ventilated vertical drop with subcritical flow at the upstream channel and sloping aprons at the downstream channel. Flow characteristics such as pool depth, downstream depth, and energy loss were measured in an 11 m length, 0.401 m width flume. The drop height was 0.21 m and inverse slope was set at 5 degrees. The last data set (case C) was measured by Lin et al. (2009) in a vertical drop with an end sill. The flume size was the same as in case A. Three vertical drop pools were used in this study with drop height H of 14.0 cm, pool length (L) of 16.0 cm, and end sill heights (h) of 0, 1.7 and 6.0 cm, such that the end sill ratios (h/H) were 0, 0.12, and 0.43 respectively. For the case A, four different grids (7908, 18901, 32729 and 57512 nodes) with identical flow properties were used. Instead of setting the depth and velocity, at the upstream end of the channel, a tank was set up so that the contracted flow depth and the average velocity (after the gate) match the selected critical depth and velocity. Pressure outlet boundary conditions (BC) were set at top of the channel, the channel outlet and at the air vent. The flow depth results were converging and a good agreement with experimental data was observed with the two smallest grids. However, to access better resolution, the 57512-node grid was preferred and grids with almost the same cell size were adopted for other numerical simulations. The laminar model did not produce satisfactory flow depth and velocity along the drop structure. The results of the most commonly used two-equation turbulence models (k- and k-) were identical. Furthermore, the standard wall function produced better results compared to non-equilibrium wall function. Thus the standard k- with the standard wall function was preferred for other simulations.
    Grid study showed that numerical results of a 57512-node grid had the best agreement with the experimental values. The desired downstream channel length was preferred to be 1.5 meter, and the standard k-ε turbulence model produced the best results in a horizontal apron drop. The numerical free-surface profiles followed the theoretical equations very well. Due to higher circulation ratio and occurring a hydraulic jump in the pool, the greatest energy dissipation was obtained in the drop with an end sill. The drop with adverse apron was in the second position and the minimum dissipation occurred in the horizontal apron drop. The numerically calculated velocity profiles mimicked the experimental results all over the falling, sliding or skimming jet regions. The numerical model was not so successful in the mixing region behind the nappe which is possibly due to weakness of the turbulence models. Using enhanced turbulence model will decrease discrepancies in this region. It can be concluded that the 2D numerical model is able to produce satisfactory results in order to design and evaluate a vertical drop, which in turn can aviate the need to endeavor too much effort and financial cost to construct a suitable experimental model in the laboratory.
    Keywords: Subcritical flow, Turbulence model, Free-surface, Velocity characteristics, Energy loss
  • Shamohammadi, Shayan Page 45
    One of the most important goals of absorption studies on aqueous solutions is determination of the maximum adsorption capacity. During the past hundred years, a number of models have been offered in this area. But none of them have an important mathematical theory, except Langmuir Isotherm model and also to some extent the model by Brunner et al. (1938). Isotherm models have two aspects in common with Langmuir model: 1) the model’s independent variable is equilibrium concentration of solution (C_e) and 2) the maximum capacity of the absorbent is only related to the equilibrium adsorption isotherm (q_e) part.
    For the first time, Langmuir wrote equilibrium relationship between two different phases. Though Langmuir tests were performed for gas adsorption at first, this theory was generalized to include equilibrium adsorption between two liquid and solid phases later. In fact, Langmuir equilibrium relationship is between vacant sites of absorbent surface (S), occupied surface sites (AS) and the solution concentration (A) which is written in relation (1). He believed that adsorption occurs only in one layer. In the other words, when the absorbent surface is completed with a single layer of absorbed material (adsorbate), adsorption would stop and adsorption capacity will reach to its maximum threshold. Langmuir equilibrium reaction is as follows:(1)
    Where, K_a and K_d are adsorption and desorption equilibrium constants, respectively. Therefore, according to the principle of equilibrium in chemistry, relation (1) is written as relation (2):K_a [A][S]= K_d [AS] (2)
    Where, K_a [A][S] is the absorption rate of reaction (〖r.〗_ads) and K_d [AS] is the desorption rate of reaction (〖r.〗_des); they become equal at equilibrium state of the system.
    Parameter [A] shows the equilibrium concentration of adsorbate which is expressed in terms of moles per liter (or milligrams per liter), and [AS] & [S] are quantities related to the absorbent surface expressed in terms of moles per square centimeter (or milligrams per square centimeter). Langmuir introduced symbol θ for parameter[AS]. Θ is a fraction (percentage) of the surface covered (occupied) by adsorbate. Therefore, (1-θ) or [S] is a fraction (percentage) of the absorbent surface which is vacant. On the other hand, if [A] is shown by symbolC_e, considering the previously mentioned concepts and relations (1) and (2) we will arrive at:The adsorption rate is proportional to the equilibrium concentration and the vacant site of the absorbent surface.
    Keywords: Adsorption, desorption rate, Assumptions, Langmuir model, Isotherm models
  • Ahmadi Nik, Ahmad, Rahimi Khoob, Ali Page 53
    In recent years in the field of agriculture and drinking water, Condensation Irrigation system combining with a solar desalination system and an irrigation system has been proposed. Condensation Irrigation system is a new idea in the field of fresh water supply. The importance of providing fresh water in the critical situation, using solar energy in purification of saline water, reduces the costs and supply of water. Considering the important issues of environmental pollution control in the form of fresh water resources indicates the need of further studies in this field. Desalination by solar radiation is one of the efficient ways to filter sea water and regarding the renewable solar radiation energy application as a way to provide sweetwater is regarded in line with sustainable development and adaptable to the environment. Since the ultimate goal of an irrigation system with any type of operational procedures is the preparation of crop water requirement, Therefore, evaluation of water supply by the irrigation system and crop water requirements is essential and is a criteria for acceptance or rejection the proposed system.
    Solar Still is the major component in compression condensation system that is responsible for providing water. Solar Stills utilize solar radiation for sea water desalination. In this study, the potential of Solar Stills evaporation and crop water requirement of Maize were evaluated at different growth stages. This project studies were carried out in the South East of Tehran (Pakdasht). Accordingly four designs of Solar Stills were used. The Solar Stills dimensions were 30*30, 34*34, 40*40 and 45*45 centimeter. The material of the Solar Stills walls was made of Plexiglass sheets. To compare between crop water requirement and evaporation from Solar Still, Spring Maize plant is considered as the sample plant due to its row cultivating and it will be irrigated by condensation irrigation system. In the Cultivation period (125 days), the Maize evapotranspiration was calculated in CROPWAT 8.0 by using meteorological data of the study area. In this software, all calculations related to reference evapotranspiration are based on the FAO 56 principles and Penman-Monteith method. Information about plants characteristics such as plant name, date of planting, during periods of growth, the crop coefficient of different growth stages, characteristics of the depth of the root and management information for each stage of growth were entered in software according to the recommendations FAO56 publication and consultation with local experts. Finally, the crop coefficient and average of the plant evapotranspiration were calculated using software in millimeters per day and also millimeters per several decades of plant growth. Based on the observations, the maximum daily evaporation of the Solar Still occurred in late July (about 8.5 mm per day). The results of the Solar Still evaporation measurements showed high efficiency of this system in the study area and the positive influence of climatic conditions on the Solar Still.
    The results indicate that evaporation rate of the Solar Still at all periods of growth is more than crop water requirement and in some growth stages, a square meter of Solar Still is able to supply about three meters of maize water requirement. Evaporation Variations in Solar Still follow the same process as crop water requirement variations and it has influenced atmospheric parameters and environmental conditions during growth period similar to crop water requirement. The amount of water vapor in the Solar Still is one of the most effective parameters on controlling the evaporation that achieving the optimum point to discharge water vapor in the Solar Still can significantly increases the power of Solar Still evaporation. The results of the present study in terms of evaluating Solar Stills evaporation potential compared with spring maize water requirement and it is noteworthy that in spite of the simplicity of the Solar Still in this project, evaporation from Solar Stills is higher than maize water requirement at all stages of significant growth and in some stages its ratio increased to three times. So regarding the performance of the compression system used in salt water, potential of solar stills was remarkable and the need for further studies in the field of promotion of evaporation potential of the Solar Stills reveal. By increasing the potential of Solar Still evaporation with new technologies, it is predicted that the amount of water produced by this system can be increased to an acceptable level.
    Keywords: Condensation irrigation system, Desalination, Evapotranspiration, Solar energy, Sea water
  • Hashemi Madani, Farkhondeh Sadat, Bani Habib, Dr M Page 63
    In recent years, water supply systems for municipal, industrial and agricultural uses have been faced with critical conditions (especially in arid regions) under the influence of human activities and his economic development and industrialization. This affects quality of life of communities particularly societies in arid regions, so the planning and management of water resources has become essential to improve the quality of life of communities. Sustainable watershed management requires collaboration of specialists in social sciences, natural sciences, water resource managers, planners and politicians. The complexities of evaluation indicators in water resources management and also the conflicts of interest between the farmers, other stockholders and policy-makers are among the reasons that necessitated the use of Multi-Criteria Decision Making (MCDM) methods for water resources planning. Numerous applications of MCDM methods have shown that they are useful tools in decision-making for water resources planning and management. The best evaluation criteria to achieve the prospect of sustainable development are indicators of sustainable development. Thus, the most appropriate prioritization to implement strategies can be obtained by evaluating sustainability of strategies with regard to sustainable development criteria. Literature review shows that the application of MCDM methods in water resources management can provide acceptable results for water resources planning. In most previous studies, the use of MCDM methods in water resources management has been in levels of reservoir management or farm management. In this study, the MCDM methods have been used for prioritizing water resource management strategies in different parts of a dry area. Thus, we addressed it in this research to provide an appropriate model to involve sustainable development criteria in choosing the best sustainable water resources management strategy for an arid region in central desert of Iran.
    The Shahrood Township is one of the eight cities in the Semnan Province. This Township is located in the north eastern part of Iran, in the north part of a desert and southern slopes of the Alborz Mountains. The hydrological and meteorological records of the Semnan Province shows that this region has cold and dry climate based on the Domarten index. The rivers that flow in this area are not permanent. Most of these rivers are mountainous with low water which only in times of high rainfall cause floods and flow to the Kavir plain. This region which is one of the arid regions of Iran is faced with water shortage, and so the strategic management of water resources based on sustainable development can improve future water resources management in this region.
    In this study, to determine the long-term strategy for water resources management in the region, a hybrid of brain storming with MCDM methods of Simple Additive Weighting (SAW) and Analytic Hierarchy Process (AHP) were used. In the brain storming session sufficient information was notified to meeting members with a description of the problem and objectives and then the opinions and ideas were produced and finally the best of them were selected. Using this method nine (9) different water resources management strategies in the Semnan province were obtained for the assessment by the MCDM models. Sustainable development criteria used in this study were obtained from previous water resources studies. These criteria were weighted at the meeting of experts. The results of the surveys have uncertainty due to the uncertain, imprecise and not defined elements in the judgments. In order to reduce errors arise from this uncertainty, the sensitivity analysis were performed on the results for ±20% changes in criteria weights.
    The results showed that the strategy of the “study and implementation of spatial planning” in SAW model and the strategy of “supervision of aquifer pumping” in AHP are top-ranked.
    The minimum acceptable score for each strategy in order to satisfy the sustainable development was determined as 50% of weights, and this was not observed by “inter-basin water transfer strategy” in application of AHP model. So this strategy is not suggested for implementation.
    In addition, sensitivity analysis showed that the SAW and AHP models were more sensitive to changing “Socio-cultural acceptability” and “Environmental conservation” criteria weights that have high weights among other criteria. The AHP model is less sensitive than SAW model with regard to criteria’s weights but its ranking is almost similar to SAW model. Therefore, determination of long-term strategy for water resources management is recommended by AHP model.
    Keywords: analytical hierarchy process, Strategic water resources management, simple additive weighting, sustainable development, multi-criteria decision making
  • Hezareh, Reza, Hassani, Uossef, Shayanmehr, Samira Page 73
    Water is considered as the most important factor and limiting input for Agriculture in dry regions as well as Iran. Studies illustrate that decrease of 10% in water supply, causes the 0.8% decrease in GDP of Iran. Accordingly, improvement of water consumption structure in this country can be a solution for solving the water crisis. In light of the future of water shortage in this country, many economists and planners have proposed the different approach and theories which may lead to a remedy for the problem of water resources. The implementation of water productivity system, especially in agricultural sector, is one of the most important solutions which have been suggested for improving this condition because the water productivity in this sector has the lowest amount compared with other economic sectors such as industry and service.
    On the other hands, the amount of supplied water is limited and the cost of supply is enormous, so improving productivity indicators has become as one of the most important policies in water resources management. The various tools are used in water resources management policies to cope with increasingly severe water shortage in the most developed and developing countries . One of the solutions have been suggested for improvement water productivity is water demand management. The policies such as water pricing, tax on inputs, tax on productions, and water supply control can affect water demand, consequently, it has a positive effect on the increase of water productivity. The objective of this paper is the assessment of the impacts of agricultural sector policies on water productivity in Qazvin plain. This research focuses on the Qazvin plain which is located in the center of the Northern Iran. The most widely used irrigation system is traditional irrigation. The population growth, low rate of water productivity, inefficient allocation of water and inappropriate cropping pattern are considered as major problems in this area.
    For achieving the goal of this research, it was applied positive mathematical programming methods and maximum entropy in Qazvin Plain between 2011 and 2012.
    Policy makers, especially those in the agricultural sector, are expected to be aware of the consequences of different policies and take into account farmers’ reactions to various policy situations and look for a simulation model that can ultimately help them make better decisions. The conventional method to simulate the decisions of economic agents is to create a model which reflects the limitations, opportunities, and the goals for the current situation. The PMP, which is an empirical analysis method, is of particular importance in the political economy analysis that incorporates all the available information no matter how rare. The increasing need for model simulation of behavioral functions under various technical, economic, political and environmental conditions has strengthened using the PMP with calibration capabilities that do not have the problem of excessive specialization and results in models with more parameters validation and flexibility.
    In this paper, three kinds of policies were designed. 1-the increase of water price 2- a tax on input and output 3- water supply policy. The reaction of farmers was stimulated by positive mathematical programming. There are the different approach for calculation the water productivity that we used from three criteria physical productivity criterion, economic productivity criterion, and employment productivity criterion.
    The results show that in addition to being water resources management policy leads to reduce water consumption, there is also economic and social effects which should be considered to the policy implementation. Also, the policy of a tax on output and input have no significant effects on physical productivity of water for other crops. On the other hands, water price policy can be as the best tools for reduction of water consumption although this policy and plan can have a negative impact on total gross margin and employment. So, it is necessary to consider all of the consequences of this policy. Furthermore, the results of productivity indices show that combined of water pricing policies (25 % increase in price) and decrease water availability (20%) provide the best situation for promotion of water productivity in Qazvin plain. Consequently, the government can improve the water productivity by the formulation of water price and water supply policies in agricultural sector.
    Water is considered as the most important factor and limiting input for Agriculture in dry regions as well as Iran. Studies illustrate that decrease of 10% in water supply, causes the 0.8% decrease in GDP of Iran. Accordingly, improvement of water consumption structure in this country can be a solution for solving the water crisis. In light of the future of water shortage in this country, many economists and planners have proposed the different approach and theories which may lead to a remedy for the problem of water resources. The implementation of water productivity system, especially in agricultural sector, is one of the most important solutions which have been suggested for improving this condition because the water productivity in this sector has the lowest amount compared with other economic sectors such as industry and service.
    Keywords: Productivity water, Maximum entropy, Qazvi, Water pricing
  • Zareie, Soheila, Fakherifard, Ahmad, Asadi, Esmaiel Page 85
    Climate change with population growth makes the water resources an important issue in Iran. Drought is an abnormal dry period which lasted for a long time. Frequency analysis of drought and prediction of drought deficit volume (drought severity) for a determined period and return period are the most important issues in drought studies. Frequency analysis is a technique of fitting a probability distribution to a series of observations for providing the probabilities of future occurrences. Also, this technique is the statistical analysis of series that have a suitable probability distribution. Inappropriate temporal and spatial distribution of rainfall exacerbate water resources management problems in addition to rainfall deficit. We can consider drought as an inappropriate temporal distribution of rainfall, So we feel the necessity of drought studies in different aspects. There are various studies for meteorological, hydrological and agricultural droughts but it seems we have not any specific research about relationship between intensity and duration frequency of both meteorological and hydrological droughts. Therefore, the purpose of this study is to determine a consolidated statistical indicator based on meteorological and hydrological droughts in regional scale.
    This drought study is described in Soufi-Chai basin with 265 km2 in East Azerbaijan which is located in northwestern Iran. The monthly flow and precipitation data of Soufi-Chai's stations was used. The observed data consists of 40 years (480 months) period between 1970 and 2011. Then the monthly precipitation data have been classified by using Thiessen Polygon for meteorological droughts and the monthly flow data of Tazeh-Kand station in outlet was considered for hydrological droughts. In order to extract the amount of drought periods for both flow and precipitation, monthly normal regime method was applied. Monthly normal series show a long-term average for each month of a year that presents monthly normal regime for a normal year. Anomaly series for both flow and precipitation data were made by subtracting flow and precipitation data from monthly normal series. In fact, we considered monthly normal series as base level and amounts under this level (negative amounts) introduced as dry periods. Then these droughts was converted to the volume deficits that showed by duration one month, two months, …and up to twelve months. In order to fit suitable distribution and extract IDF (Intensity- Duration- Frequency) curves, frequency analysis upon volume deficit was done by using statistical distribution methods. In this study, SMADA software was used for frequency analysis. In this work, root mean square error (RMSE) were used to assess different distributions. For various return periods (2, 3, 5, 10, 25, 50, 100 and 200) the precipitation and flow drought volume deficits were calculated by using Normal and Pearson type III distributions. We eliminated temporal factor and only based on various return periods for extracting a model which shows a relationship between both meteorological and hydrological droughts. At first, a statistical model was obtained separately for each drought and then a new index was created by eliminating temporal factor as below:This index is an exponentially equation which only related to return period. For investigating performance of this index, correlation coefficient (R) was used. R values had high amounts that shows a desirable result for this equation. This index is so important in reservoirs and dam management.
    As a result of this study, we considered average amount as a management line, so that, drought will be the precipitation or flow under the average. The meteorological and hydrological drought graphs show that in most years, hydrological drought has not occurred in those months which have meteorological drought, because of some reasons such as delay in snow melting. So hydrological droughts have occurred in few months later. Therefore, it takes time to affect different elements of hydrologic system like river, reservoirs and underground waters by precipitation deficit. A comparison between IDF curves showed that hydrological droughts take place with more intensity rather than meteorological droughts. Then forecasting hydrological droughts by meteorological droughts done by frequency analyzing. The results showed that Normal distribution has the least root mean square error (RMSE) for precipitation volume deficits in duration from one month to nine, respectively: (1.07, 1.950, 2.043, 1.917, 1.924, 1.981, 2.641, 3.515, 5.489) and Pearson type ш for flow volume deficits (1.179, 2, 2.663, 3.101, 3.508, 3.812, 4.321, 4.828, 5.029). By using these statistical distributions, severity- duration- frequency curves were extracted and an appropriate mathematical equation based on correlation coefficient and also the least error has been selected. Then the relationship between meteorological and hydrological droughts was earned exponentially independent of time and only based on frequency. The results of this study are very noteworthy for droughts management.
    Keywords: Statistical indicators, Soufi-Chai basin, Hydrological drought, Monthly normal regime, Meteorological drought, Frequency analysis
  • Arabzadeh, Rezgar, Araghinejad, Shahab, Amirkhani, Masoud, Jalali Borban, Aram Page 93
    Industrialization and human overpopulation are among the major reasons of environmental pollution and especially the pollution of water resources systems. Human activities can contribute to upsetting the delicate balance of nature by polluting air, soil, and water resources. The environment has the ability to recover from damages caused by pollutants, however, the problem is that this ability is limited and the process is time consuming. Nowadays, studying groundwater systems and providing new methods and managerial tools has become a widespread activity among water resources planners and managers. Since majority of Iran’s water demand is provided by groundwater and aquifers, there has to be a meaningful accentuation and notes on both qualitative and quantitative characteristics of water extracted from this kind of water resources systems as a strategic and a decisive phenomenon in regional planning. Groundwater, which is a major source of domestic, industrial, and agricultural water supply worldwide, is less susceptible to different types of water pollutants in comparison with surface water. Nevertheless, monitoring and remediation of groundwater pollution are more complicated and expensive than that of surface water pollution. Spatial variability and lack of data make groundwater remediation more difficult or even impractical. Therefore, pollution prevention must be considered as an immediate action for an effective management of groundwater resources.
    The vulnerability assessment of groundwater system is a good practice for modelling and planning to preserve and protect these valuable systems from pollutions. Quantifying how and where groundwater systems are prone to be polluted is termed as vulnerability assessment. The tendency of contaminants originated from the land surface to reach water table is termed as groundwater vulnerability. National Research Council defines two types of groundwater vulnerability: specific vulnerability and intrinsic vulnerability. Intrinsic vulnerability is independent of the nature of water resources system, while specific vulnerability takes into account the susceptibility of groundwater to particular contaminants. Groundwater vulnerability assessment is a tool for protecting and qualitative management of these valuable resources. So, in this paper a well-known groundwater vulnerability model is used to assess aquifer vulnerability to pollutants. Different approaches such as indexing, statistical analysis, and process-based methods have been proposed for assessing the vulnerability of groundwater to pollutants and delineating vulnerable areas of aquifers. GOD, DRASTIC, AVI, SINTACS, RISKE, and DRAV are examples of indexing methods. This study proposes Dehgolan aquifer vulnerability assessment using DRASTIC technique. DRASTIC index is calculated as a linear combination of factors affecting the groundwater vulnerability to pollutants. In the present study, Generalized Reduced Gradient 2 (GRG2) algorithm was used to create an optimized weighted linear combination of the factors used in DRASTIC method based on gridded images to establish the aggregated vulnerability model. As a good criterion to evaluate the efficiency of this model, Spearman Correlation Rank Test (SCRT), between Groundwater vulnerability Index and Nitrate (NO3) concentration was carried out that was equal to 0.493. The optimization-simulation in this study includes a simulator of DRASTIC model with a given vector of candidate weights by optimization algorithm and the GRG2. The GRG2 algorithm could reach the desired value of SCRT with the minimum number of iteration. Then for evaluating this criterion, model’s parameters were optimized using (GRG2) algorithm and the correlation coefficient as objective function.
    The optimized correlation was computed as 0.651. The study results, found optimization procedure as good idea in vulnerability assessment, where there is low or insignificant relationships between what is modeled using vulnerability technique and extend of observed pollutions in groundwater system. Optimization process showed the approach taken in the study useful in balancing and deriving reasoning multiplicative weights in a realistic groundwater vulnerability assessment. Even though, the study proposes a procedure for weights delineation of DRASTIC vulnerability method, it does not optimize number of subdivisions and sub-weights. Hence, further study would tune the method so that describes vulnerability condition concordant to observed pollutions. This study showed that although in vulnerability assessment, inaccurate data and uncertainty caused poor relationship for the vulnerability index and the current condition of the aquifer, the optimization approach could tune a desirable groundwater vulnerability map for regional planning. Finally, it is to say, the procedure which is described in this paper can be used for many aquifers and different groundwater systems for assessing their accurate vulnerability condition.
    Keywords: Dehgolan, Aquifer, GRG2, Vulnerability, DRASTIC
  • Seyed Kaboli, Hesam Page 101
    Reservoir storage is essential for developing dependable water supplies and is a major component of the river system water budget. The storage contents of reservoirs fluctuate greatly over time with variations in water use and hydrologic conditions that range from severe multiple-year droughts to floods. Water surface evaporation typically represents a major component of the reservoir water budget. Estimates of the amount and rate of evaporation from open water surfaces are required in water resource management for a variety of purposes, such as the design of storage reservoirs, catchment water balance studies, municipal and industrial water supply, irrigation of agricultural lands and management of wetlands. The impacts of reservoir evaporation on water management vary greatly based on location with differences in climate, reservoir characteristics, and water management and use practices. Determining evaporation rates is essential for efficient management of reservoirs and water resources, particularly in water-scarce countries such as Iran. It is estimated that open water reservoirs in Iran lose high volume of their total water storage capacity per year by evaporation. For example, this loss is around 13% of the volume of inflow to KHARKHEH Dam per year. While this loss is of significant concern, the threat of a changing climate has been directing greater focus to how much water will be lost from Iran’s reservoirs in the future. As a result of the change in climate, particularly the increase in surface air temperatures, evaporation is also expected to increase throughout Iran. This paper analyses evaporation rates from Dez dam reservoir for the two periods (2021-2050 and 2051-2080) under modeled climate change conditions using five General Climate Models (GCMs) with A2 emission scenario. Global climate models, also known as general circulation models (GCMs), are models which solve the primitive equations of mass, momentum and thermodynamics to generate a description of the state of the atmosphere, and produce most of the meteorological variables, such as wind speed, relative humidity, rainfall, surface air temperature and solar radiation. The GCMs are typically used together, as a multi-model analysis, where long time series into the future and different GHG emission scenarios are used in order to create climatic statistics. Inherent to GCMs, however, is their coarse spatial resolution which amongst all the available models varies from 200 to 500 km. With this resolution, albeit GCMs incorporate the important large-scale atmospheric circulation, they are unable to capture local-scale factors such as the orographic elevation, proximity to water bodies and local winds. Therefore, the outputs of GCMs need to downscale for applying to modeled evaporation. Daily meteorological prepared using K-NN downscaling model to estimate evaporation rate from open surface water using equations derived from penman equation. The K-NN downscaling model is a nonparametric resampling method for generating new data series. This method simulates daily precipitation for a weather station by combining a stochastic weather generator model (based on non-parametric K-Nearest Neighbor approach) with future climate scenarios that are established based on projected monthly. In this study, an equation based on penman equation for situations where no wind data are available is used to estimate evaporation rate. The equation is validated by compared to the penman equation in estimating the evaporation rate in a meteorological station that has the same climate as DEZ dam. Then, evaporated volume, which is estimated using area-capacity relations of Dez dam, were compared with observed meteorological variables for the period of 1982–2011. Area-capacity curves are usually used for reservoir flood routing, reservoir operation, determination of water surface area, and capacity corresponding to each elevation, reservoir classification, and reservoir sediment distribution. In this study, a dimensionless curve is used to estimate the changes of capacity in relation to the changes of evaporation rate. Results of the application of the presented model for downscaling monthly precipitation outputs of GCMs show that the model has a high capability for downscaling precipitation. So, the used equation to estimate the evaporation rate is suitable for applying in DEZ dam station. Also, the results showed that the volume of average annual evaporation from the study reservoir will increase about 7% in 2021-2050 and 10% in 2051-2080 more than base period. The main reason of this increase can be global warming in the future. According to the modelling results, the mean annual air temperature will be increased by 1.3C and 3C in 2021-2050 and 2051-2080 respectively. This will have a significant impact on the evaporation rates, especially in spring and summer which the increases in temperature will be too high.
    Keywords: Climate Change, Dam Reservoir, Downscaling, GCMs, Emission Scenario, Penman equation
  • Nadiri, Ataallhah, Rozrokh, Jamil, Asgharimoghaddam, Asghar Page 111
    This study investigated the hydrogeology and hydrogeochemical processes of groundwater in the Harzandat plain aquifer. The Harzandat basin shown in Figure 1 is located northwest of Tabriz, the city in the northwest region of Iran. It is a subbasin of the Khazar basin. The Harzandat basin is about 347 km2. This includes 146.7 km2 of the Harzandat plain and 200.3 km2 of Mountainous areas. The highest elevation of the Harzandat basin is 2623 m above mean sea level (amsl) at the old Harzandat and the lowest elevation is 1,274 m amsl at Zal railway station. Based on de Martonne (1925) and Emberger (1930), the prevailing climate in the Harzandat plain is arid-cold. Average annual precipitation is about 219 mm (Chercher climatological station, 2012-2013).
    In the last decades, this aquifer suffered from severe groundwater level declination and caused degradation of groundwater quality. To better understand of hydrogeochemical processes in Harzandat plain, groundwater samples obtained 77 from 16 different water wells, springs and qanats between 2002 and 2013 and used them to characterize the hydrogeochemistry of the Harzandat plain aquifer. The location of the sample sites is shown in Figure 3. The samples were analyzed in the hydrogeological laboratory of University of Tabriz and in the laboratory of East Azerbaijan Regional Water Authority. The water quality parameters of interest were , , , , , , , and , which were determined by the standard methods (American Public Health Association 1998). Moreover, pH, electric conductivity (EC), the total dissolved solid (TDS) were measured from the samples. Total hardness (TH), sodium absorption ration (SAR), and sodium percent (Na%) were calculated from the measured chemical parameters. Samples collected from groundwater resources were analyzed through the graphical and multivariate statistical methods.
    Graphical methods (e.g., a Piper diagram, a Durov diagram, a Stiff diagram, etc.) are commonly used to interpret hydrogeochemical processes (Stiff 1951; Piper 1944; Hem 1986; Durov 1948; Lloyd 1965). Piper diagrams were used to deduce groundwater types and an expanded Durov diagram improves the Piper diagram by providing a better display of different types of water as well as important hydrochemical processes, such as ion exchange, simple dissolution and mixing of waters with different qualities. A Stiff diagram compares analytical data in pairs and infers types of source rocks (Stiff 1951; Hounslow 1995). Although the graphical methods are commonly used to interpret hydrogeochemical processes, they have several limitations as they cannot analyze neutral chemical species (e.g., SiO2 and ) and nonchemical data (e.g., temperature) (Voudouris et al. 1997).
    Multivariate statistical methods (e.g., factor analysis (FA) and hierarchical clustering analysis (HCA)) are able to complement the limitations of the graphical methods for hydrogeochemical process interpretation (Cloutier et al. 2008). Multivariate statistical analysis is able to explain the correlation among a large number of variables and reduce the number of variables into a small number of factors without loss of essential information. In multivariate statistical methods, factor analysis was frequently used to investigate hydrogeochemical origins (Voudouris et al. 2000). Factor analysis was also applied to investigating groundwater contamination. Clustering analysis was used as a classification technique for hydrogeochemical type investigation and the interpretation of their origin (Cloutier et al. 2008).
    The results of the Piper diagram shows two groundwater types and the Stiff diagram showed six different sources of groundwater samples. The Durov diagram identified two major hydrogeochemical processes in the aquifer. However, Hierarchical Cluster Analysis (HCA) identified five water types in the groundwater samples, because HCA was able to use more chemical and physical data than graphical methods. The HCA result was checked by discriminant analysis method and the classification accuracy of groundwater resources samples and confirmed by this method. Based on the factor analysis method, four main effective factors were found on the hydrochemistry of the Harzandat plain aquifer. First, second and third factors show the effect of geological formation and general groundwater trend on hydrochemistry of the area. The fourth factor seems to be related the influence of human activities. In the first factor, chloride, sulfate, magnesium, calcium and electrical conductivity, and in the second factor percentage of sodium and sodium absorption ratio, and in the third factor potassium and bicarbonate is effective, while, in the fourth factor carbonate were related to nitrate and acidity. In fact, the first, second and third factors are geogenic, and the fourth factor is anthropogenic.
    Keywords: Hydrogeochemistry, Harzandat plain, Multivariate statistical analysis, Graphical method
  • Taghian, Mehrdad Page 123
    Over the past decades, solving operation problems has been a challenge for water resource planners and managers. Holistic standpoint and integrated management have been applied as a replacement for traditional and partial insight in water resource development projects in recent years. Hence, one of the operator's key questions in multi-reservoirs systems is that which reservoirs should be depleted earlier for satisfying shared downstream demands. In addition, to refill the reservoirs, which ones should be filled earlier? Accordingly, multi-reservoir operation in water resource systems should be done to maximize the total water extracted. In this case, one of the important parameters affecting the system performance is ranking and prioritizing the reservoirs storages for supplying the shared downstream demands. In fact, refill and deplete order of cascade or parallel reservoirs are effective on the reservoir storage distribution. This approach can make also direct effects on the total losses including spill and evaporation of the reservoirs, reforming the total regulated water obtained of reservoir dams.
    In this paper, a simulation model with a linear programming optimizing engine is utilized for operational ranking of the reservoirs during a long-term monthly inflow period. Simulation has been implemented for monthly time interval using inflow historical data. In this study, Acres Reservoir Simulation Program (ARSP) has been utilized including a linear programming for optimal water allocation and reservoir storage within each time interval. The main advantage of the ARSP is its inherent flexibility in defining the operating policies through a penalty structure. The model uses network flow optimization techniques in which total components of the system are made through nodes and arcs. Nodes are including reservoir dams, withdrawal and return flow locations, irrigation and water supply networks, and junction points for river reaches or streams. Arcs include different kinds of stream, canals, river reaches and different zone of reservoir dams. Nodes and arcs totally fulfill a closed network that characterizes final structure river system. There are arcs connecting reservoirs and demand nodes to the source and sink node. The source node supplies water to nodes within the network to simulate local inflow and the sink node receive flow from nodes within the network to represent consumptive use. In this state, certain number of arcs defines each stream and storage zone in reservoir. In fact, each arc represents an operating purpose, for which a comparative penalty representing relative priority of desired purpose can be assigned by the user. Based on this penalty for unit flow violation, ARSP imposes the operational strategy by allocating the available water in a manner that minimizes the total system penalties. In selecting these penalty values, three specific aspects should be considered: inter-reservoir zonal operation, relation between storage and flow violation, and inter-reservoir policies. In this process, the reservoirs are ranked according to priority relationships. The model first violates the storage in the lowest priority corresponding to the lowest zonal penalty, and then it proceeds to the other priorities.
    As a case study, the seven reservoirs system of Zohreh water resource in southwest of Iran has been studied. A future planning horizon was selected for the study including seven reservoir dams, eleven irrigation networks, four public demands, two minimum flow channels, eleven junctions node, and some general channels. Target values for demands are also set based on the planned water demand for future horizon distributed as 71% for agriculture demands, 16% for the minimum flow, and 13% for public demands. To evaluate the long-term performance of reservoir operation, 48 years of monthly inflow is used, resulting in a total of 576 months. The other input data are reservoir properties, penalty values, evaporation from reservoir, and return flows. Here, different scenarios have been defined for the ranking of the reservoirs. This approach has been effective about 6% on decreasing the water losses including spillway and evaporation of reservoir. The comparison among different scenarios showed that reservoirs ranking affects in all modern indicators for the operation performance. Based on flexibility index, storage ranking in parallel reservoirs is more effective than cascade reservoirs. In this process, reliability and vulnerability indexes were improved for the selective scenario, however, resiliency index was reduced a little. Moreover, reservoirs refill order from upstream to downstream of the catchment, in comparison with opposite state, accomplished better performance as in this state the possibility for spill control in the next reservoir is better provided.
    Keywords: Linear programming, Simulation, Reservoir ranking, Zohre basin, Optimization
  • Hassannezhad Sharifi, Farzam, Samadi, Dr A., Azizian, Asghar Page 133
    Some characteristics of rivers that are dependent upon particle-size distribution such as riverbed grain-size (e.g., D50, D84 or D90), can be estimated using different methods which the commonest is sieving analysis. Nowadays, recent innovations in image processing techniques make it possible to determine the gradation curve through digital photographic methods. Images are processed using a default or selective algorithm in most image processing softwares including GIAS, ImageJ, and similar programs for Windows (e.g., Scion Image and ImageTool) and other operating systems. Up to the present time, numerous studies were conducted using image processing of sediment particles for a variety of purposes that mostly is introducing the image processing as a replacement for traditional methods of particle size determination (i.e., sieve analysis, Wolman pebble count, etc.) in order to save time, money, energy and labor force. According to the importance of image processing and itsapplication in river engineering and drawing sediment gradation curve and also difficulties in field surveys to take appropriate images of sediments at different points of the area, it seems necessary to know the appropriate dimensions of sediment surface in order to accurate processing of their particles. In our study, the accuracy of image processing technique (using FHWA Hydraulic Toolbox software) to carry out an appropriate evaluation of grain-size of surface layer sediments of Shalmanroud riverbed were evaluated by processing sedimentary layers of two images with different size. In addition, usage possibility of the results obtained using this method has evaluated for determining representative diameters of sediment particles in some measuring methods for bed load. After some visits from Shalmanroud River to select an appropriate study site, a 7.5 kilometer length of the river was chosen and some photos of riverbed sediments and required samples were taken for more examination. At 25 points along the river reach with uniform sediment, some photos were taken from about one meter above riverbed surface at each point using a 10-megapixel Canon's PowerShot G12 digital camera and the available equipments. At each point, two images were captured from above the sediments that one is related to surface particles inside a 70cm×70cm wooden frame and the other is related to surface sediment particles inside a 40cm×40cm wooden frame (which is fixed in the middle of the larger frame). Then, the surface particles were gathered and stored in special storage bags for the sieve analysis. At each point in the field, the UTM coordinates were measured using the Garmin handheld GPS. The samples were delivered to the soil mechanics laboratory for sieve analysis. In order to plot grain-size curve of sieve analysis, cumulative percentage retained on each sieve was determined. Next, to achieve more accurate estimate of the grain-size distribution using image processing technique, the FHWA Hydraulic Toolbox software was used. Digital image processing consists of eight separate fundamental steps. 1 - Former M.Sc. Student of Hydraulic Structures, Water Engineering Department, Faculty of Engineering and Technology, Imam Khomeini International University, Qazvin, Iran. 2& 3- Assistant Professor,Water Engineering Department, Faculty of Engineering and Technology, Imam Khomeini International
    The results of image processing had been entered into Excel, and then particle-size distribution curves were immediately obtained. Then, the values of representative diameters, i.e., D16, D50, D75 and D84 were read from the particle-size distribution curves (laboratory and software). After that, to examine the correlation and linear regression between the sieve result and the result of image processing, correspondence analysis was run in Excel software and the values of the correlation coefficients for D16, D50, D75 and D84 diameters were computed 0.93, 0.936, 0.905 and 0.824, respectively (obtained from processing of images using a 40cm×40cm wooden frame). In a similar way, those values were obtained for results of image processing using the 70cm×70cm wooden frame as follows: 0.864, 0.876, 0.877 and 0.823, shows a strong correlation between lab test results and image processing results. The results revealed that the estimated diameters using the 40cm×40cm frame are closer to the experimental values than what the 70cm×70cm frame estimated. It was also revealed that in the case of using 40cm×40cm wooden frame, the estimation accuracy increases as the diameters increase; whereas the converse results were obtained with the larger frame. It was revealed that the error of estimate for finer particles was larger for particles smaller than D50than that of particles larger than D50. Image analysis using FHWA Hydraulic Toolbox software is sensitive to the size of the frame so that in the case of using the smaller frame (40cm×40cm), the estimates of the particle size are likely to be more accurate and show positive relationship with particle size while this relationship turns negative when a larger frame is used. Regarding the wide range of particle sizes (from very fine gravel to small pebble) on Shalmanroud Riverbed and also the higher accuracy of image processing in estimating larger particles (in case of using the smaller frame), it is highly recommended to use Meyer-Peter and Muller formula for computation of
    Keywords: Sieve analysis, Image processing, FHWA Hydraulic Toolbox 4.2, Gradation curve, Bed-surface sediments
  • Khaleghi, Mehdi, Zeinivand, Hossein, Haghizadeh, Ali Page 143
    In this study, efficiency of WetSpa model to simulate daily runoff, sensitivity analysis parameters and their impacts on various components of the hydrological cycle was investigated in Khorramabad river in Lorestan Province using the PSET method. Watershed digital maps of elevation, soil and land use, time series of precipitaion, evapotranspiration and temperature are the main input data of the hydrological WetSpa model. The Observed discharge data at Doab Veisian station for the period of 2004-2010 (1383-1389 in Iranian solar calendar) was used for the model calibration and validation. Based on the results, the model is able to simulate the flow rate during the statistical period, so that simulated and observed data have NS coefficient around 83.76 and 66.44 for calibration and validation respectively (In confidence level of 95%). In analyzing the sensitivity of the model parameters, it was observed that the surface runoff factor for the near-zero rainfall intensity is the most sensitive, and the degree-day rainfall factor has the least sensitivity. The gmax parameter with the least sensitivity produces the greatest uncertainty in the simulation, and the accurate estimation of this parameter is almost impossible. The parameters of snow melt like T0 and Ksnow in the simulation of spring and autumn floods are not affected by rainfall, and sensitivity of these parameters is related to snow storms that occur in the winter. Krun and Pmax parameters have high sensitivity in the simulation of flood hydrographs and these parameters have a negative correlation with each other, affecting the flood discharge hydrograph, and have the greatest effect on the runoff simulation uncertainty band. Therefore, it is important to determine the appropriate range of the changes in these parameters in the simulation of flood hydrograph.
    In this study, efficiency of WetSpa model to simulate daily runoff, sensitivity analysis parameters and their impacts on various components of the hydrological cycle was investigated in Khorramabad river in Lorestan Province using the PSET method. Watershed digital maps of elevation, soil and land use, time series of precipitaion, evapotranspiration and temperature are the main input data of the hydrological WetSpa model. The Observed discharge data at Doab Veisian station for the period of 2004-2010 (1383-1389 in Iranian solar calendar) was used for the model calibration and validation. Based on the results, the model is able to simulate the flow rate during the statistical period, so that simulated and observed data have NS coefficient around 83.76 and 66.44 for calibration and validation respectively (In confidence level of 95%). In analyzing the sensitivity of the model parameters, it was observed that the surface runoff factor for the near-zero rainfall intensity is the most sensitive, and the degree-day rainfall factor has the least sensitivity. The gmax parameter with the least sensitivity produces the greatest uncertainty in the simulation, and the accurate estimation of this parameter is almost impossible. The parameters of snow melt like T0 and Ksnow in the simulation of spring and autumn floods are not affected by rainfall, and sensitivity of these parameters is related to snow storms that occur in the winter. Krun and Pmax parameters have high sensitivity in the simulation of flood hydrographs and these parameters have a negative correlation with each other, affecting the flood discharge hydrograph, and have the greatest effect on the runoff simulation uncertainty band. Therefore, it is important to determine the appropriate range of the changes in these parameters in the simulation of flood hydrograph.
    In this study, efficiency of WetSpa model to simulate daily runoff, sensitivity analysis parameters and their impacts on various components of the hydrological cycle was investigated in Khorramabad river in Lorestan Province using the PSET method. Watershed digital maps of elevation, soil and land use, time series of precipitaion, evapotranspiration and temperature are the main input data of the hydrological WetSpa model. The Observed discharge data at Doab Veisian station for the period of 2004-2010 (1383-1389 in Iranian solar calendar) was used for the model calibration and validation. Based on the results, the model is able to simulate the flow rate during the statistical period, so that simulated and observed data have NS coefficient around 83.76 and 66.44 for calibration and validation respectively (In confidence level of 95%). In analyzing the sensitivity of the model parameters, it was observed that the surface runoff factor for the near-zero rainfall intensity is the most sensitive, and the degree-day rainfall factor has the least sensitivity. The gmax parameter with the least sensitivity produces the greatest uncertainty in the simulation, and the accurate estimation of this parameter is almost impossible. The parameters of snow melt like T0 and Ksnow in the simulation of spring and autumn floods are not affected by rainfall, and sensitivity of these parameters is related to snow storms that occur in the winter. Krun and Pmax parameters have high sensitivity in the simulation of flood hydrographs and these parameters have a negative correlation with each other, affecting the flood discharge hydrograph, and have the greatest effect on the runoff simulation uncertainty band. Therefore, it is important to determine the appropriate range of the changes in these parameters in the simulation of flood hydrograph.
    Keywords: WetSpa model, PEST, Sensitivity analysis, Daily flow, Khorramabad River
  • M.R. Tabari, Dr Mahmoud, Tavakoli, Shiva, Shalchi Tabrizi, Amir Page 149
    The circular weirs are one kind of broad crested weirs that have some advantages such as being economic, simple designing and high discharge coefficient in comparison with the other alternatives. High curvature of the stream lines over this kind of weirs is one of affecting factors on the discharge coefficient. The study of discharge coefficient in the circular weirs, due to changes of hydraulic conditions, is very important in the design and application of these structures. In this research, the flow has been studied over 3 groups of circular weirs with diameters 6.3, 9.0 & 11.4 cm, using the numerical model of FLOW-3D. Further, the method of finite volume was used to solve the extant equations and the model of RNG was also used to investigate the flow turbulence. The results have been presented as velocity profiles and discharge coefficient which was calculated for different discharge rates. The results of this numerical model were compared with experimental results for these groups of circular weirs, and a proper agreement has been observed between them.
    The circular weirs are one kind of broad crested weirs that have some advantages such as being economic, simple designing and high discharge coefficient in comparison with the other alternatives. High curvature of the stream lines over this kind of weirs is one of affecting factors on the discharge coefficient. The study of discharge coefficient in the circular weirs, due to changes of hydraulic conditions, is very important in the design and application of these structures. In this research, the flow has been studied over 3 groups of circular weirs with diameters 6.3, 9.0 & 11.4 cm, using the numerical model of FLOW-3D. Further, the method of finite volume was used to solve the extant equations and the model of RNG was also used to investigate the flow turbulence. The results have been presented as velocity profiles and discharge coefficient which was calculated for different discharge rates. The results of this numerical model were compared with experimental results for these groups of circular weirs, and a proper agreement has been observed between them.
    The circular weirs are one kind of broad crested weirs that have some advantages such as being economic, simple designing and high discharge coefficient in comparison with the other alternatives. High curvature of the stream lines over this kind of weirs is one of affecting factors on the discharge coefficient. The study of discharge coefficient in the circular weirs, due to changes of hydraulic conditions, is very important in the design and application of these structures. In this research, the flow has been studied over 3 groups of circular weirs with diameters 6.3, 9.0 & 11.4 cm, using the numerical model of FLOW-3D. Further, the method of finite volume was used to solve the extant equations and the model of RNG was also used to investigate the flow turbulence. The results have been presented as velocity profiles and discharge coefficient which was calculated for different discharge rates. The results of this numerical model were compared with experimental results for these groups of circular weirs, and a proper agreement has been observed between them.
    The circular weirs are one kind of broad crested weirs that have some advantages such as being economic, simple designing and high discharge coefficient in comparison with the other alternatives. High curvature of the stream lines over this kind of weirs is one of affecting factors on the discharge coefficient. The study of discharge coefficient in the circular weirs, due to changes of hydraulic conditions, is very important in the design and application of these structures. In this research, the flow has been studied over 3 groups of circular weirs with diameters 6.3, 9.0 & 11.4 cm, using the numerical model of FLOW-3D. Further, the method of finite volume was used to solve the extant equations and the model of RNG was also used to investigate the flow turbulence. The results have been presented as velocity profiles and discharge coefficient which was calculated for different discharge rates. The results of this numerical model were compared with experimental results for these groups of circular weirs, and a proper agreement has been observed between them.
    The circular weirs are one kind of broad crested weirs that have some advantages such as being economic, simple designing and high discharge coefficient in comparison with the other alternatives. High curvature of the stream lines over this kind of weirs is one of affecting factors on the discharge coefficient. The study of discharge coefficient in the circular weirs, due to changes of hydraulic conditions, is very important in the design and application of these structures. In this research, the flow has been studied over 3 groups of circular weirs with diameters 6.3, 9.0 & 11.4 cm, using the numerical model of FLOW-3D. Further, the method of finite volume was used to solve the extant equations and the model of RNG was also used to investigate the flow turbulence. The results have been presented as velocity profiles and discharge coefficient which was calculated for different discharge rates. The results of this numerical model were compared with experimental results for these groups of circular weirs, and a proper agreement has been observed between them.
    Keywords: Numerical model, Flow-3D, Circular weir, Discharge coefficient