فهرست مطالب

پژوهش آب ایران - پیاپی 34 (پاییز 1398)
  • پیاپی 34 (پاییز 1398)
  • تاریخ انتشار: 1398/07/09
  • تعداد عناوین: 16
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  • سید حسین مهاجری *، اکبر صفرزاده، سیدعلی اکبر صالحی نیشابوری، مسعود قدسیان صفحات 1-8

    در شرایط جریان با جداره زبر، خصوصیات آماری جریان در ناحیه داخلی لایه مرزی علاوه بر ویژگی‌های جریان آشفته (لزجت سیال)، از ابعاد عناصر زبر نیز تاثیر می‌پذیرد. حضور اجزای زبر در بستر کانال، موجب تغییر شرایط طبیعی کانال می‌شود، زبری، جریان‌های ثانویه را تقویت و به این واسطه اثر مهمی در جابه جایی و انتقال جانبی رسوب ایفا می‌کند. در این مقاله به بررسی اثر زبری بر مشخصات هیدرولیکی جریان آشفته در یک کانال مستقیم روباز با مقطع عریض پرداخته شده است. به بیان دقیق‌تر در این مقاله مشخصات جریان در شرایط تشکیل جریان ثانویه تحت اثر زبری بررسی شده است. نتایج نشان داده که سرعت طولی و خصوصیات آشفتگی جریان در مقطع عرضی تغییر می‌کنند. ممان‌های مرتبه اول (سرعت متوسط) و مرتبه دوم (شدت آشفتگی) در اثر تشکیل جریان ثانویه از معادلات تئوری موجود انحراف پیدا می‌کنند. این تغییرات و انحراف از معادلات تئوری در نقاط نزدیک به جداره مشهودتر است. به علاوه تنش برشی نیز در مقطع عرضی تغییرات محسوسی از خود نشان می‌دهد. دامنه نوسان تنش برشی در مقطع عرضی، 35% تنش برشی متوسط است.

    کلیدواژگان: بستر زبر، جریان های ثانویه، جریان آشفته، کانال روباز، مطالعه آزمایشگاهی
  • پیش بینی سرعت جریان و بررسی تاثیر زبری کانال ها بر هیدرولیک جریان در آبگیرهای جانبی بوسیله ترکیب شبکه عصبی مصنوعی و مدل عددی CFX
    سهراب کریمی، حسین بنکداری، آزاده غلامی صفحات 9-18

    آبگیرهای جانبی، از رایج‌ترین سازه‌های هیدرولیکی مورد استفاده در سیستم‌های انتقال آب هستند. هدف این پژوهش، بررسی تاثیر زبری کانال‌ها بر هیدرولیک جریان و پیش‌بینی سرعت در آبگیرهای جانبی با استفاده از ترکیب شبکه عصبی مصنوعی و مدل عددی است. مدل آزمایشگاهی کانال آبگیر 90 درجه با جداره صاف توسط نرم‌افزار ANSYS CFX شبیه‌سازی شده است. بعد از صحت‌سنجی و اطمینان از دقت بالای نتایج مدل CFX، با استفاده از داده‌های آزمایشگاهی و عددی، اقدام به طراحی پنج مدل شبکه عصبی مصنوعی در پنج زبری مختلف شده است. سرعت‌های طولی جریان توسط مدل ANN در مقاطعی که داده‌های آزمایشگاهی موجود نمی‌باشد، پیش‌بینی و با نتایج مدل CFX مقایسه شده است. با توجه به نتابج مدل ANN با افزایش زبری کانال‌ها از 0/0 به 0005/0 متر، سرعت‌های طولی در اکثر مناطق کانال فرعی، افت قابل توجهی دارند؛ اما با افزایش زبری از 0005/0 تا 001/0 متر و بیشتر از آن، سرعت‌های طولی جریان افت اندکی دارند. با افزایش زبری، ابعاد ناحیه جدایی جریان کاهش می‌یابد و در ورودی کانال فرعی انحنای خطوط جریان و آشفتگی جریان نیز کاهش می‌باید.

    کلیدواژگان: آبگیرهای جانبی، زبری کانال، سرعت جریان، مدل ANN، نرم افزار ANSYS CFX
  • مهدی امانلو*، محمدرضا یافتیان، عبدالحسین پری زنگنه، عباسعلی زمانی صفحات 19-26

    پایش منابع آبی آلوده، با توجه به گسترش شهرنشینی و انواع آلودگی، موضوع مهم مدیریت منابع آبی است. به‌منظور تعیین غلظت برخی فلزهای سنگین به‌عنوان مهم‌ترین آلودگی در آب شرب شهر زنجان، نمونه‌برداری به سه روش در ایستگاه‌های نمونه‌برداری انجام شد. تعداد 120 نمونه از 40 ایستگاه در بافت قدیم، 60 نمونه از 20 ایستگاه در بافت جدید شهر و 20 نمونه از تصفیه‌خانه برداشت شد. اندازه‌گیری فلزهای سنگین در نمونه‌های آب به روش ولتامتری برهنه‌سازی نشان داد که غلظت یون‌های مورد مطالعه از ترتیب Zn>Cu>Pb>Cd پیروی می‌کند. مقایسه میانگین فلزهای سنگین با استانداردهای جهانی، کیفیت مطلوب آب را در زمان نمونه‌برداری تایید می‌کند. تنها مقدار کادمیم و سرب به‌ترتیب در 2/5 و 3/6 درصد از نمونه‌ها بیشتر از حد استاندارد جهانی هستند. میانگین مقدار فلزهای سنگین در محل ایستگاه‌های نمونه‌برداری نسبت به نمونه‌های مربوط به تصفیه‌خانه آب شهر افزایش یافت. مقدار این فلزها در بافت قدیم شهر پس از 8 ساعت ماند آب در شبکه افزایش نشان داد. با توجه به نتایج به‌دست آمده و توزیع جغرافیایی آن‌ها، آزاد شدن یون‌های فلزی از لوله‌های گالوانیزه فرسوده در شبکه آبرسانی شهری، مهم‌ترین منبع افزایش غلظت فلزهای سنگین در آب شهر زنجان شناخته شد.

    کلیدواژگان: ایستگاه هیدرومتری، سناریوهای انتشار گازهای گلخانه ای، مدل HadCM3، مدل LARS WG، مدل رگرسیون وزن دار جغرافیایی
  • الهام کدخدا، غلامعباس فلاح قالهری*، محمد باعقیده، سید علیرضا فرید حسینی صفحات 27-38

    هدف در این پژوهش، ارزیابی پیامدهای تغییر اقلیم بر افت سطح آب‌های زیرزمینی دشت مشهد است. بدین‌منظور از آمار ماهانه بارندگی 34 ایستگاه همدیدی، اقلیم‌شناسی و باران‌سنجی منطقه، دبی ماهانه 13 ایستگاه هیدرومتری و سطح آب زیرزمینی 60 حلقه چاه پیزومتری، استفاده شده است. برای پیش‌بینی متغیرهای اقلیمی آینده از داده‌های مدلHadCM3 استفاده شده است. داده‌های دما و بارش منطقه توسط مدل LARS-WG5.5 برای دو دوره 2030-2015 و 2065-2046 تحت سه سناریوی انتشار گاز گلخانه‌ای A1B، A2 و B1 ریزمقیاس شدند. برای مدل‌سازی سطح آب زیر‌زمینی از مدل رگرسیون وزن‌دار جغرافیایی (GWR) استفاده شده است. ارزیابی تغییرات بارش دشت مشهد در دهه‌های آینده، حاکی از کاهش بارش در فصل سرد و افزایش آن در فصل گرم است. بررسی‌های دمایی نیز حاکی از افزایش حداقل یک‌درجه‌ای دما نسبت به دوره پایه است. مدل‌سازی سطح آب زیر زمینی دشت مشهد با پارامترهای اقلیمی نشان داد مدل GWR از توانایی خوبی برای برآورد افت سطح آب‌های زیرزمینی برخوردار است. نتایج به‌دست آمده تحت هر سه رویکرد تغییر اقلیم، بیان‌کننده افت سطح آب کلیه چاه‌های پیزومتری مورد مطالعه در دوره‌های آینده است. بیشترین کاهش سطح آب زیرزمینی مربوط به رویکرد A1B در دوره 2065-2046 بود و رویکردهای A2 و B1 در رتبه‌های بعدی قرار دارند.

    کلیدواژگان: ایستگاه هیدرومتری، سناریوهای انتشار گازهای گلخانه ای، مدل HadCM3، مدل LARS WG، مدل رگرسیون وزن دار جغرافیایی
  • مینا تاج آبادی، علینقی ضیایی، کامران داوری*، عزیزالله ایزدی صفحات 39-50

    هدف از این پژوهش، مدل سازی کمی آبخوان بجنورد با تاکید بر لایه بندی آن می باشد. در این مطالعه مدل سه بعدی لیتولوژی آبخوان با استفاده از تکنیک های مدل سازی سه بعدی در نرم افزار Rockworks، با اطلاعاتی نظیر لاگ چاه های بهره برداری و مطالعات ژئوفیزیک بدست آمده است. مدل لیتولوژی بدست آمده آبخوان که شامل چهار گروه بافت خاک درشت دانه، متوسط دانه و ریزدانه و خیلی ریزدانه است، به صورت چهار لایه با ضخامت 30 متر به نرم افزار GMS وارد شد و در شرایط ماندگار اجرا شد که مجذور میانگین مربعات خطا بعد از کالیبراسیون به مقدار 794/0رسید به طوریکه مجذور میانگین مربعات خطا، نسبت به مدل تک لایه که دارای مقدار 0.852هست، بهبود یافته است. مقاطع عرضی بدست آمده بیانگر وجود عدسی ها و ناهمگنی رسوبات آبخوان بجنورد می باشد که در صحت تخمین هدایت هیدرولیکی بسیار تاثیرگزار هستند. مقادیر هدایت هیدرولیکی در شرایط ناهمگنی آبخوان به صورت موضعی و با توجه به جنس های مختلف موجود با مقادیر 1/8، 7/6، 9/1 و 4/0 متر بر روز به ترتیب برای بافت خاک درشت دانه، متوسط دانه، ریزدانه و خیلی ریزدانه بدست آمد. چکیده کامل نیست چکیده کامل نیست چکیده کامل نیست چکیده کامل نیست چکیده کامل نیست چکیده کامل نیست چکیده کامل نیست چکیده کامل نیست چکیده کامل نیست چکیده کامل نیست چکیده کامل نیست چکیده کامل نیست چکیده کامل نیست چکیده کامل نیست

    کلیدواژگان: هدایت هیدرولیکی، بجنورد، مدل لیتولوژی، GMS. Rockworks
  • محمد علی شاهرخ نیا*، لادن جوکار صفحات 51-62

    استفاده از فرمول های تجربی برآورد نشت آب در کانال ها در مقایسه با روش های عملی، باعث صرفه جویی در وقت و هزینه می گردد. با توجه به تجربی بودن، ارزیابی و واسنجی این فرمول ها ضروری است. در این پژوهش، نشت آب در سه کانال آبیاری دشت داراب فارس، با استفاده از 9 فرمول تجربی برآورد و با روش مستقیم دبی ورودی- خروجی مقایسه شد. روابط تجربی برای کانال های مذکور مورد واسنجی و صحت سنجی قرار گرفت. نتایج اولیه نشان داد فرمول موریتز و آفنگندن با داشتن خطای 49% و 1445% به ترتیب دارای کمترین و بیشترین تفاوت با روش دبی ورودی-خروجی و خطای بقیه فرمول ها حدود 125% است. نتایج حاصل از واسنجی نشان داد که فرمول های اینگهام، مولس ورث-ینی دومیا، دیویس ویلسون، موریتز و آفنگندن با داشتن خطای نسبی کمتر از 10%، مطابقت خوبی با روش دبی ورودی- خروجی دارند. پس از این فرمول ها، فرمول گارگ، آبیاری مصر، میسرا و پنجاب هند، بترتیب با داشتن خطای 16، 18، 20 و 20 درصد در رده های بعدی هستند. نتایج صحت سنجی نشان داد فرمول های موریتز و میسرا به ترتیب دارای بیشترین و کمترین مطابقت با روش مستقیم در شرایط مورد بررسی هستند.

    کلیدواژگان: کانال آبیاری، داراب، فرمول تجربی، نشت آب
  • فواد کیلانه ئی*، حمیدرضا منعمی، امیر محجوب صفحات 63-74

    در این مقاله اثر درصد تراکم و مقدار ریزدانه خاک بر مقدار نفوذپذیری خاک SC و جریان نشت از گوره های مهارسیلاب در حالت دائمی و غیردائمی مورد بررسی قرار گرفته است. بدین منظور سه نمونه ی منتخب خاک که در این تحقیق با نام های A، B و C مشخص شده اند و به ترتیب دارای درصد ریزدانه 12، 8/20 و 4/28 می‌باشند، با درصد تراکم های 100، 85، 70 و 60 مورد آزمایش نفوذپذیری قرار گرفته اند. نتایج نشان داد با افزایش درصد تراکم در هر یک از نمونه های مورد بررسی از مقدار 60 به 100، 70 به 100 و 85 به 100 ضریب نفوذپذیری به ترتیب به مقدار متوسط 25، 3/14 و 91/8 برابر کاهش داشته است. در هر درصد تراکم نیز مقدار ضریب نفوذپذیری نمونه A به طور میانگین 2/1 برابر نمونه B و 69/1 برابر نمونه C و ضریب نفوذپذیری نمونه B به طور میانگین 41/1 برابر نمونه C تعیین گردیده است. در ادامه با مدلسازی عددی پدیده تراوش، دبی عبوری از گوره های مهار سیلاب با درصد تراکم‌‌های مختلف در حالت تراوش دائمی و سطح فریاتیک در حالت تراوش غیردائمی مورد بررسی قرار گرفته است.

    کلیدواژگان: گوره مهار سیلاب، جریان دائمی و غیردائمی، ضریب نفوذپذیری، درصد تراکم، درصد ریزدانه، مدل عددی
  • کاربرد الگوریتم بهینه سازی غذایابی باکتری (BFO) جهت تخمین ضرایب یکنواختی توزیع آب در سیستم آبیای بارانی
    حسن ترابی، الهه حسینیان صفحات 75-84

    یکی از پارامترهای مهم در کشاورزی، ضریب یکنواختی توزیع آب (CU) در آبیاری بارانی می‌باشد. مقدار CU حاصل از هر آب‌پاش در مقادیر مختلف فشار کارکرد آب‌پاش، ارتفاع پایه آب‌پاش‌، فاصله آب‌پاش‌ها روی لوله‌های جانبی و فاصله لوله‌های جانبی از یکدیگر تغییر می‌یابد. تعیین بهترین ترکیب از پارامترهای فوق که بالاترین ضریب CUرا حاصل نماید، همواره سئوالی بی‌جواب برای کاربران بوده است. در این پژوهش، مقادیر ضریب CU آب‌پاش مدل zb ساخت ایران در 3 تیمار مختلف فشار کارکرد آبپاش ، 2 تیمار ارتفاع پایه آب‌پاش و 7 تیمار آرایش شبکه آبپاش‌ها که در ایستگاه تحقیقات پنبه هاشم‌آباد گرگان اندازه‌گیری شده‌است، با استفاده از الگوریتم غذایابی باکتری بهینه گردید و رابطه‌ای با بهینه‌ترین ضرایب برای تخمین مقدار CU با استفاده از پارامترهای ذکر شده توسط این الگوریتم بدست آمد. در این الگوریتم پارامترهای Nc، Nre، Ned و C(i) به ترتیب برابر 500، 8،8 و 01/0 بهترین جواب را ارائه می‌کنند. نتایج نشان داد این الگوریتم دارای خطای مطلق 2 درصد می‌باشد. همچنین مقدار پارامتر ریشه‌ی دوم میانگین مربع خطا برابر 13/2 بدست آمد که نشان دهنده دقت بالای این مدل برای برآورد ضریب یکنواختی پخش می‌باشد.

    کلیدواژگان: الگوریتم غذایابی باکتری، ضریب یکنواختی، توزیع آب، آبیاری بارانی
  • محمد هوشمند*، سعید برومند نسب، محمد الباجی، ناصر عالم زاده انصاری صفحات 85-94

    کم آبیاری از مدیریت های به کار رفته برای کسب محصول با درآمد و سود بیشینه در سال های اخیر به دلیل تشدید بحران آب مورد توجه قرار گرفته است. در این پژوهش اثر روش های آبیاری تنظیم شده (RDI) وخشکی موضعی ریشه (PRD) بر گوجه فرنگی در شرایط کشت هیدروپونیک بررسی گردید. تیمارهای آزمایش شامل تیمارهای آبیاری RDI در دو سطح 85 و 70 درصد نیاز آبی گیاه، آبیاری PRD در دو سطح 85 و 70 درصد نیاز آبی گیاه که به صورت متناوب آبیاری را انجام می دادند و شاهد در قالب طرح کاملا تصادفی با چهار تکرار اجرا گردید. نتایج نشان داد که شیوه ها و سطوح مختلف کم آبیاری بر وزن تر و خشک ریشه، وزن تر و خشک ساقه، وزن خشک بوته، وزن میوه و کارایی مصرف آب محصول و بخش هوایی تاثیر معنی دار دارد ولی بر وزن تر و خشک و میزان آب برگ، سطح برگ، شاخص سطح برگ، سطح برگ ویژه، نسبت سطح برگ، وزن بیوماس و شاخص برداشت تاثیر معنی داری نداشته است. بیشترین وزن میوه در بوته و کارایی مصرف آب در تیمار PRD85 به میزان به ترتیب 2572/5 گرم و 16/07 کیلوگرم بر متر مکعب و کمترین آن در تیمار PRD70 به میزان به ترتیب 1189/5 گرم و 9/02 کیلوگرم بر مترمکعب بدست آمد. همچنین کم آبیاری به صورت خشکی موضعی ریشه با سطح 85% نیاز آبی گیاه به عنوان بهترین روش برای کشت هیدروپونیک گوجه فرنگی انتخاب شد.

    کلیدواژگان: خشکی موضعی ریشه، کارایی مصرف آب، کشت بدون خاک، گوجه فرنگی، کم آبیاری
  • کیوان نادری، عطا الله ندیری*، اصغر اصغری مقدم، مهدی کرد صفحات 95-106

    تغییرات سطح آب‌زیرزمینی، یکی از مهم‌ترین متغیرها در مدیریت آبخوان‌هاست که پیش‌بینی دقیق این متغیر می‌تواند در ارائه راهکارهای مدیریتی برای حفظ این مخازن آب شیرین استراتژیک به‌خصوص در مناطق خشک و نیمه‌خشک، مانند حوضه دریاچه ارومیه راهگشا باشد. با وجود توانایی بالای مدل‌های هوش مصنوعی (AI) در پیش‌بینی سطح آب‌زیرزمینی به‌دلیل ناهمگنی و ناهمسانی محیط‌های هیدروژئولوژیکی، گه‌گاه از کارایی پایینی برخوردارند؛ از این‌رو، استفاده از روش هوشمند نگاشت خود سازمان‌ده (SOM) برای خوشه‌بندی چاه‌های مشاهده‌ای و ترکیب آن با مدل‌های مختلف هوش مصنوعی می‌تواند باعث بهبود نتایج حاصل از مدل‌سازی شد. در این پژوهش، روش‌های مختلف SOM-AI، شامل ماشین ‌بردار پشتیبان (SOM-SVM) و مدل فازی ساگنو (SOM-SFL) برای پیش‌بینی تغییرات سطح آب‌زیرزمینی به‌کار گرفته شدند. بدین‌ترتیب، چاه‌های مشاهده‌ای (OW) در سه گروه G1، G2 وG3 دسته‌بندی و برای هر گروه از چاه‌های مشاهده‌ای مدل‌سازی سطح آب زیرزمینی اجرا شد. ارزیابی نتایج با استفاده از معیارهای RMSE، r2 و NSE نشان داد که حداقل در سه چاه مشاهده‌ای OW2، OW6 و OW9، مدل ترکیبی SOM-SFL عملکرد بهتری نسبت به بقیه داشت. در بقیه چاه‌های مشاهده‌ای مدل ترکیبی SOM-LSSVM برتری نسبی داشت.

    کلیدواژگان: سطح آب زیرزمینی، منطق فازی، ماشین بردار پشتیبان، نگاشت خود سازمان ده
  • ابراهیم محمدی سلیمانی*، مجید احمدیان، محسن شوکت فدایی، علی کرامت زاده، ابوالفضل محمودی صفحات 107-116

    هدف این مقاله، بیان وضعیت سفره آب زیرزمینی دشت جیرفت در دهه ‌اخیر و مقایسه هزینه سالانه پمپاژ آب از چاه در دو نوع تکنولوژی برداشت آب با پمپ دیزل و الکتروپمپ است. بدین منظور از اطلاعات بهره‌برداران چاه‌های آب کشاورزی دشت جیرفت در سال زراعی 95-1394 استفاده شد. نتایج نشان داد که متوسط هزینه پمپاژ یک مترمکعب آب با استفاده از الکتروپمپ و پمپ دیزلی به‌ترتیب 169 و 365 ریال بود. به عبارتی، هزینه سالانه پمپاژ آب توسط الکتروپمپ نسبت به پمپ دیزل در حدود نصف کاهش می‌یابد. مقدار صرفه‌جویی سالانه در هزینه پمپاژ آب و در نتیجه کاهش هزینه جاری کشت یک هکتار گندم و پرتقال، در نتیجه تغییر نوع تکنولوژی برداشت آب چاه از پمپ دیزلی به الکتروموتور به‌ترتیب برابر 1525670 و3815920 ریال خواهد بود. نتایج نشان داد که سود درازمدت کشاورزان در نتیجه تغییر تکنولوژی برداشت از پمپ‌های دیزل به الکتروپمپ بدون به‌کارگیری محدودیت‌های فیزیکی و یا تعرفه‌ای منجر به فشار بیشتر بر منابع آب زیرزمینی دشت و افزایش سرعت تخلیه آن شده است.

    کلیدواژگان: الکتروپمپ، هزینه پمپاژ، دشت جیرفت، سفره آب زیرزمینی
  • احسان توکلی*، بهزاد قربانی، علیرضا توکلی صفحات 117-126

    با توجه به اهمیت حیاتی آب در مناطق خشک و نیمه‌خشکی چون ایران، حفاظت و استفاده بهینه از منابع آب امری ضروری است. پژوهش حاضر با هدف تحلیل اقتصادی پوشش در کانال‌‌‌‌‌‌‌‌های انتقال آب انجام شد و در آن به بررسی اقتصادی نفوذ از کانال بدون پوشش به آب زیرزمینی و پمپاژ دوباره آب از طریق چاه، در مقایسه با نگهداشت آب در کانال‌‌‌‌‌‌‌‌ پوشش شده پرداخته شد. برای انجام این پژوهش، کانال بتنی شبکه آبیاری و زهکشی گندمان و بلداجی، در شهرستان بروجن استان چهارمحال و بختیاری، با مقطع ذوزنقه و عرض کف 3/1 متر، عمق 8/1 متر و عرض بالای 5/6 متر انتخاب و با کانال خاکی با ابعاد مشابه مقایسه گردید. داده‌‌‌‌‌‌‌‌های اولیه شامل الگوی کشت انتخابی و سطح زیر کشت، عملکرد و مصرف آب گیاهان در بازه زمانی پژوهش و هزینه کارگری قبل و بعد از پوشش کانال بود. برای محاسبه هزینه‌‌‌‌‌‌‌‌های پوشش کانال، با فرض عمر مفید 10، 20 و 40 ساله پوشش، هزینه عملیات خاکی، هزینه پوشش‌‌‌‌‌‌‌‌دهی کانال، ارزش آب صرفه‌‌‌‌‌‌‌‌جویی شده، کاهش هزینه تعمیر، لایروبی و نگهداری و امکان توسعه کمی و کیفی محصولات زراعی و باغی در سطح زیر پوشش کانال انتقال، درنظر گرفته شد. به منظور محاسبه هزینه‌‌‌‌‌‌‌‌های پمپاژ آب زیرزمینی از اعماق مختلف نیز، هزینه‌‌‌‌‌‌‌‌های انرژی، استهلاک سامانه پمپاژ لحاظ گردید. نتایج نشان داد در هر سه نرخ تنزیل 12، 15 و 18 درصد و با هر سه عمر مفید 10، 20 و 40 سال، همواره کانال خاکی توجیه اقتصادی بیشتری نسبت به کانال بتنی دارد. همچنین، با افزایش عمر مفید کانال بتنی از 10 به 40 سال (در نرخ تنزیل ثابت)، ارزش حال خالص و نسبت سود به هزینه ابتدا افزایش و سپس کاهش نشان داد. بررسی دقیق محاسبات نشانگر آنست که پس از 30 سال، با حداکثر شدن مخارج نگهداری کانال پوشش‌‌‌‌‌‌‌‌دار، هزینه‌‌‌‌‌‌‌‌های آن فراتر از درآمدهای حاصل خواهد شد، بنابراین پوشش با شرایط ذکر شده پس از 30 سال توجیه اقتصادی نداشته و شاخص‌‌‌‌‌‌‌‌های اقتصادی مورد بررسی نسبت به قبل کاهش می‌‌‌‌‌‌‌‌یابند. بنابراین، پوشش‌‌‌‌‌‌‌‌دار کردن کانال در منطقه بروجن استان چهارمحال و بختیاری در مقایسه با گزینه کانال خاکی و پمپاژ دوباره از چاه، توجیه اقتصادی ندارد. نتایج نشان داد در هر 3 نرخ تنزیل 12، 15 و 18 درصد و با هر 3 عمر مفید 10، 20 و 40 سال، همواره کانال خاکی توجیه اقتصادی بیشتری نسبت به کانال بتنی دارد. بنابراین، پوشش دار کردن کانال در منطقه بروجن استان چهارمحال و بختیاری در مقایسه با گزینه کانال خاکی و پمپاژ دوباره از چاه، توجیه اقتصادی ندارد

    کلیدواژگان: شبکه آبیاری و زهکشی گندمان و بلداجی، کانال پوشش دار، کانال خاکی، مدل سازی فیزیکی
  • کاربرد رویکرد بیلان جرمی در ارزیابی تغییرات تبادل آب های سطحی و زیرزمینی در حوضه لنجانات
    سیدعلی اصغر هاشمی شیخ شبانی، روح الله فتاحی نافچی، حسین صمدی بروجنی صفحات 127-136

    در سال‏های اخیر استخراج بیش از حد آب از منابع آب آبخوان‏ها در سراسر کشور، پایداری منابع آب زیرزمینی را تهدید کرده است. لذا شناخت ارتباط بین آب سطحی و آب زیرزمینی و تبادلات حجمی بین آنها از اهمیت بالایی برخوردار است. در این مطالعه بر اساس بیلان آب سطحی و جریان ماهانه چهار ایستگاه آبسنجی، بازای هر ماه معادله‏ای برای خروجی هر بازه رودخانه استخراج شد. پارامترهای این معادله، بیانگر ارتباط خالص آب سطحی با جو و آب زیرزمینی می باشند. سری تاریخی داده‏ها به دو دوره بیست ساله تقسیم شد و تبادل آب در دو دوره مقایسه شدند. نتایج مطالعه بر روی سه بازه موجود نشان داد که در بازه اول طی دو دوره، آب زیرزمینی بطور خالص تغذیه کننده آب سطحی بوده است. آب سطحی بازه انتهایی، در دوره اول تغذیه کننده آب زیرزمینی بوده در حالیکه در دوره دوم در اکثر ماه‏ها بوسیله آب زیرزمینی تغذیه شده است. در خشکسالی شدید بجز بازه اول، دو بازه دیگر دچار کمبود آب شدند. یافته‎ها نشان داد که افزایش آب سطحی بوسیله آب زیرزمینی، اهمیت بالایی در تامین آب در شرایط خشکسالی دارد. بر اساس نتایج، روش ارائه شده ابزار مناسبی در بررسی تبادل آب سطحی با آب زیرزمینی می‏باشد.

    کلیدواژگان: تبادل، آب سطحی، آب زیرزمینی، جریان ورودی و خروجی، بیلان جرمی، بازه رودخانه
  • مهرداد نوروزی *، مختار زلفی باوریانی صفحات 137-146

    در دهه‌های اخیر استفاده از آب‌های شور در تولید کشاورزی به دلیل کاهش منابع آب شیرین رشد چشمگیری داشته است. ولی استفاده بی خطر از آب شور مستلزم مدیریت صحیح آبیاری است. این پژوهش به منظور بررسی اثر شوری آب بر عملکرد، کارایی مصرف آب و کیفیت میوه گوجه‎فرنگی تحت روش آبیاری قطره‎ای نواری طی یک فصل زراعی (90-1389) در استان بوشهر با شرایط آب و هوایی خشک و نیمه خشک اجرا شد. آزمایش به صورت کرت‎های خرد شده در قالب طرح بلوک‌های کامل تصادفی با چهار سطح شوری آب آبیاری (شامل 1/1، 5/3، 5/5 و 5/7 دسی‌زیمنس بر متر) و سه سطح دور آبیاری (شامل 2، 4 و 7 روز) با سه تکرار انجام شد. طبق نتایج، با افزایش دور آبیاری از 2 روز به 7 روز مقادیر میانگین‎ عملکرد محصول(Y)، کارایی مصرف آب آبیاری (IWUE) و وزن میوه (FW) به ترتیب 20، 19 و 26 درصد کاهش داشتند. همچنین، با افزایش شوری آب آبیاری از dS.m-1 1/1 به dS.m-1 5/7 این مقادیر به ترتیب 33، 39 و 32 درصد کاهش داشتند. بطور کلی، تحت شرایط آب و هوایی و ویژگی‌های خاکی محل آزمایش کاهش عملکرد محصول در اثر شوری آب به مراتب کمتر از مقادیر گزارش شده در نشریه 29 فائو (آیرز و وستکات، 1985) بود. همچنین با افزایش دور آبیاری و شوری آب آبیاری کیفیت میوه به لحاظ میزان مواد جامد محلول (TSS) افزایش داشت.

    کلیدواژگان: آبشویی نمک، آبیاری تیپ، دور آبیاری، شوری آب آبیاری، کارایی مصرف آب
  • فریده انصاری سامانی*، سید حسن طباطبایی، فریبرز عباسی، ابراهیم علایی صفحات 147-160

    نیترات در طبیعت به واسطه فعالیت‌های میکروبی می‌تواند به نیتروژن یا دیگر شکل‌ها تغییر یافته و حذف شود. روش‌های مختلفی برای حذف نیترات از آبها وجود دارند که رایج‌ترین آنها، استفاده از بسترهای نیترات زدایی است. در این پژوهش با طراحی بسترهای نیترات زدایی حاوی مخلوطی از خاک و چهار منبع کربنی مایع شامل گلوکز، استات، اتانول و متانول عملکرد آنها برای حذف نیترات آب زیرزمینی بررسی شد. به همین منظور از یک ستون پلکسی گلاس به عنوان ستون ماریوت (منبع آب) و یک ستون پلکسی گلاس دیگر به عنوان محیط متخلخل پر شده با خاک با بافت لوم رسی به طول 50 و قطر 10 سانتی متر استفاده شد. نمک نیترات پتاسیم برای ساختن غلظت 100 میلی‌گرم بر لیتر نیترات استفاده شد. این پژوهش در دو نسبت C/N 5/1و 5/3 انجام شد و اندازه گیری غلظت نیترات خروجی تا حجم منفذی10 ادامه داشت. نتایج نشان داد با گذشت زمان، میزان غلظت نیترات خروجی کاهش یافت به طوری که با گذشت 250 ساعت از شروع آزمایش مقدار غلظت خروجی به مقدار ثابتی رسید. راندمان حذف در گلوکز 83/97، استات 97، اتانول66/98 و متانول 99 درصد بدست آمد و بنابراین متانول بیشترین کارایی را در حذف نیترات داشته و توانسته است نیترات به غلظت 100 میلی‌گرم در لیتر را به 1/2میلی‌گرم بر لیتر برساند. متانول با تعداد 131000 باکتری، بیشترین میزان رشد باکتری را در نسبتC/N 5/3 داشت. در واقع با افزایش غلظت ماده کربنی میزان رشد باکتری‌ها افزایش و میزان غلظت نیترات کاهش یافت، در نتایج حاصل از آزمون همبستگی، تفاوت میانگین‌های دو جامعه از سطح اطمینان 5 درصد کوچکتر است که اختلاف معنی‌داری بین غلظت منابع کربنی وجود داشت.

    کلیدواژگان: آلودگی، باکتری، حذف بیولوژیکی، راندمان، نرخ حذف
  • پریا نسیمی*، حمیدرضا متقیان، احمد کریمی صفحات 161-171

    ماده آلی خاک نقش مهمی در بهبود ویژگی های فیزیکی، شیمیایی و بیولوژیکی ایفا می کند. بیوچار سبب بهبود ویژگی های فیزیکی و شیمیایی خاک می شود. این پژوهش با هدف بررسی نقش زمان بر اثرات برگ خرما و بیوچار حاصل از آن بر هدایت هیدرولیکی و ضرایب رطوبتی خاک لوم شنی رسی انجام گرفت. برگ خرما و بیوچار به طور یکنواخت و به صورت پودری با خاک عبور داده شده از الک 4 میلی متری مخلوط شد و به صورت طرح فاکتوریل در قالب کاملا تصادفی با دو فاکتور زمان در چهار سطح و فاکتور برگ خرما و بیوچار هر کدام در چهار سطح در 3 تکرار انجام گرفت. هدایت هیدرولیکی اشباع (Ks)، رطوبت ظرفیت زراعی (θFC)، رطوبت نقطه پژمردگی دایم (θPWP)، آب قابل استفاده گیاه (PAWC) و ظرفیت زراعی نسبی (RFC) تعیین شدند. نتایج نشان داد تفاوت معنی داری (01/0>P) بین تیمارها وجود دارد. کاربرد 5/0، 1 و 2 درصد وزنی برگ خرما هدایت هیدرولیکی اشباع را به ترتیب 2/24، 7/17 و 3/74 درصد افزایش داد. کاربرد 5/0 درصد وزنی بیوچار 4/39 درصد کاهش و تیمار 1 و 2 درصد آن به ترتیب باعث افزایش 4/29 و 4/41 درصد در هدایت هیدرولیکی گردید. اثرات نوع ماده اصلاحی بر RFC ، θPWP و PAWC و اثر سطوح کاربرد بر همه ضرایب رطوبتی خاک افزایش معنی دار(01/0>P) بود. اثرات متقابل زمان، نوع ماده اصلاحی و سطوح کاربرد بر PAWC و θPWP در سطح آماری (01/0>P) و بر RFC در سطح آماری (05/0>P) تفاوت معنی داری دارند و این اثرات بر θFC معنی دار نبود.

    کلیدواژگان: بیوچار، هدایت هیدرولیکی اشباع، ظرفیت زراعی، نقطه پژمردگی دائم، آب قابل استفاده گیاه
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  • Seyed Hossein Mohajeri*, Akbar Safarzadeh, Seyed Ali Akbar Salehi Neyshabouri, Masooud Qodsian Pages 1-8

    Study of open-channel turbulent flow over rough bed is beneficial to provide a better understanding of many riverine physical processes. Indeed, the knowledge of rough bed turbulent flow has a significant effect on sustainable environmental management of the mountainous rivers. The structure of rough bed turbulent boundary layer in inner region is affected by bed geometry in addition to flow characteristics (e.g. viscosity). Presence of rough elements in the channel bottom makes differences between boundary layer flow over the smooth and rough beds. Presence of roughness enhances the secondary currents. The secondary currents’ enhancement can play an important role in sediments’ transversal and longitudinal transport. The secondary currents’ formation in rectangular open-channels is attributed to the side wall effects. If the channel width is small, i.e., the side walls are not too far from each other, the secondary currents are formed in whole cross-section. Accordingly, based on the channel aspect ratio (which is defined as the ratio of channel width to the water depth; i.e. B⁄H), Nezu and Nakagawa [14] classified the rectangular open-channels: First class is called narrow channels which has an aspect ratio smaller than 5. In narrow channels, the secondary currents are present in whole cross-section. The second class is wide channels where B⁄H is larger than 2.5~5. In this category, no secondary currents are formed in the channel central part (i.e. y⁄(H>2.5) where y is transversal location) and so flow characteristics do not noticeably undulate in the lateral direction. Despite many studies about narrow channels, only a few number of studies deal with secondary current presence of absence and also their characteristics in wide channels. This paper deals with turbulent flow hydraulic characteristics in straight open channel under the roughness elements’ effects, with high aspect ratio (i.e. wide channel). More precisely, in this paper, characteristics of the flow due to formation of secondary currents in the rough bed condition are studied. For this purpose a series of laboratory measurements using ADV probe were conducted which will be explained in the following section. The laboratory experiments were conducted in a straight rectangular flume, 11 m long and 1 m wide, at the Hydraulic Laboratory of Tarbiat Modares University. The channel side walls and bed were made from glass and smooth Perspex, respectively. Free surface profiles were measured with an ultrasonic distance transducer to control the flow uniformity condition. Small surface waves at the flume entrance were eliminated using a 1.5 m long and 0.95 m wide polystyrene plate held parallel to the upper water surface just at the end of the water intake. The flow rate was controlled with a gate valve and was measured using a magnetic flow meter. During experiments, four different hydraulic scenarios were performed in subcritical flow condition. A summary of the experimental conditions is reported in Table 1. Also, the rough bed characteristics during the measurements are reported in Table 2. Flow field was measured by a vectorino type 10 MHz down looking micro- Acoustic Doppler Velocimeter (ADV) capable of measuring instantaneous three velocity components. The velocity measurements were done at a sampling rate of 100 Hz over a 45 mm3 sampling volume. Each velocity point was sampled for at least 300 s in order to assure that the number of independent samples is enough for statistical analysis. In normal- and span-wise directions, distance between two consecutive measurement points were 5 cm and 5 mm, respectively. Measurements were performed in just half of the channel, after verifying symmetry of the velocity distribution with respect to the channel centerline. In addition to the flow field, the local bed shear stresses were measured using a homemade Preston tube named three-tube device in the present study. The manufactured probes were connected to four capacitive types, the Keller 41X pressure transducers using silicon tubes and so the collected data could be stored in the computer. Each point measurement with three tube pressure instrument was continued for around 300 s similar to the measurement of the velocity field, while three tube pressure instrument data were measured with frequency of 50 Hz. It has been observed that all the flow characteristics are spatially changed in transversal directions. Mean streamwise velocity and turbulent intensity profiles are diverted from available theoretical equations as secondary currents’ result. These diversions are clearer near side walls region. Also, shear stress in transversal direction is changed significantly. The undulation amplitude in transversal direction is 35% of shear stress mean value in span-wise direction.

    Keywords: Experimental study, Secondary currents, Turbulent flow, Rough bed, Open channel
  • predicting the flow velocity and Examining the effect of the roughness of channels on the flow hydraulics in intakes through using a combination of Artificial Neural Network and Numerical model CFX
    sohrab karimi, hossein bonakdari, azadeh gholami Pages 9-18

    Rivers provide water and energy for humans and the nature and it could be stated that providing water is the most crucial economic role of rivers. Water is deviated from its main course through the intakes in order to fulfill various purposes such as for agriculture, urban water supply, electricity generation and etc. Constructing the water intakes is one of the ancient cheapest methods to use the river water for different purposes. In the past, the gravity was used to collect the water from the rivers but it has now turned into an evolved hydraulic structure with designing criteria. Considering the fact that the river flow includes fine- and coarse-grained sediments and that the river regime changes during the floods, the intake’s inlet mouth must carry out the two essential duties: absorbing and controlling the flow deviated from the river and directing it into the intake channel and preventing the sediments and floating objects from entering the intake. Therefore, one of the crucial points to be considered in designing an intake located within a river is to select the conditions under which the water deviated by the intake will have maximum flow discharge and minimum sediment discharge. Using the new method, known as the soft computing, has gained significant popularity within the past decade due to the complexity of most engineering problems. One of the advantages of this method is its efficiency and desirable level of accuracy in solving complex and challenging engineering problems therefore, it brings accuracy and speed to the works of researchers. Numerous studies have been conducted to evaluate the flow in different types of open channels and hydrologic and hydraulic phenomena using the soft computing. The obtained results indicate the high accuracy of this method in solving complex water and hydraulic structures despite the few registered researches done on dividing open channel flow modeling. The present research examines the effect of the channel roughness on flow hydraulics and predicts the velocity in the intakes using a combination of artificial neural network and numerical model. The artificial neural network is an idea based on the human mind, which is widely used in solving complex problems in different sciences. An artificial neural network generally comprises a number of connected nodes (known as neurons) including an input layer, a number of hidden layers and an output layer, each layer is made up of a number of neurons. Considering that the number of the hidden layers neurons is excessively great, the network will take an unacceptably long time to train for each value. An ANN model is presented in this study in order to predict the flow mean velocity. It is essential to model and verify a numerical model in order to train the model under flow conditions where there are no available experimental data. Ramamurthy et al.’s (2007) experimental model has been used in this study in order to verify the numerical model. The experiments have been conducted within rectangular channels. The main channel is straight while the branch channel is attached to the main channel with an angle of 90 degree. Therefore, Ramamurthy et al.’s (2007) experimental model has been simulated using the ANSYS-CFX software and verified through using the existing experimental data. After assuring the simulation accuracy in the CFX, different models have been conducted using the CFX and are used in training and verifying the ANN in order to predict the flow mean velocity. The verification results, using a MAPE by 5 percent average error, indicates the high accuracy of the generated numerical model. After verifying the CFX model’s results and assuring that they were highly accurate, measures were taken to design five artificial neural network models with five different roughnesses by using the numerical and experimental data. The longitudinal velocities were predicted using the ANN model in cross sections, which possessed no experimental data, and then they were compared with the CFX model’s results. The result of this comparison indicates that the ANN model is highly accurate to predict the flow velocity in different areas of the intake channel moreover as the channel wall roughness increases from 0.0 to 0.0005 m, the flow longitudinal velocity drops significantly in most areas of the branch channel however as the roughness increases from 0.0005 to 0.001 m and more, the longitudinal velocities slightly drop. As the channel wall becomes rougher, the size of the flow separation zone decreases and the curve of the streamlines and the flow turbulence also decrease at the entrance of the branch channel

    Keywords: ANSYS CFX software, ANN model, Channel roughness, Flow velocity, Intakes
  • mehdi amanlou, mohammadreza yaftian, abdolhosein parizanganeh, abbasali zamani Pages 19-26

    Numerous articles printed in recent scientific journals about the heavy metals contamination of drinking water indicate its universal importance. These metals are commonly toxic at very low exposure levels and have acute and chronic effects on human health. Heavy metals are a multi-organ system toxicant that can cause neurological, cardiovascular, renal, gastrointestinal, hematological and reproductive effects. The type and severity of effects depend on the level, duration and timing of exposure. Heavy metals are released by various natural and anthropogenic sources to the aquatic and terrestrial environments and the atmosphere and there are fluxes between these compartments. One of the main sources of heavy metals in drinking water comes from lead service pipes and the lead pipes inside dwellings. In Iran, lead in petrol is still an important source of exposure. Other sources include lead in paint, low temperature-fired ceramics, informal sector recycling of cars batteries, mine tailings and the air, soil and dust in the vicinity of point sources (e.g., smelters). Recent studies in Iran show that the presence of lead in drinking water is mostly due to pipes, fittings, brass or bronze water service connection valves, faucets, fixtures, and other end-use devices. In this research, the heavy metal contamination of drinking water in Zanjan City from the water distribution system is studied. Two district within the city; (I) an older district with lead alloyed service pipes, and (II) a newer district with plastic water mains (polypropylene) were selected. Random periodic spot samples were taken manually to investigate the pollution incidents. The samples were collected in 1000 ml polyethylene bottles. The polyethylene containers were washed with dilute detergent and distilled water, then rinsed thoroughly with tap water and at last washed with an aqueous 10% nitric acid solution, drained and immediately caped. A few drops of concentrated ultra-pure HNO3 were added to the samples to reach pH < 2 in order to prevent the loss of metals and bacterial and fungal growth. To ensure the removal of organic impurities from the samples and thus preventing interference in analysis, the samples were preserved and digested with concentrated nitric acid. A total number of 200 water samples were taken using three different sampling methods, namely; 1) Fully flushed sampling: The Fully flushed sample is a sample taken after prolonged flushing of the tap in a premise in such way that water stagnation in the domestic distribution system does not influence the concentration of lead. In practice, a sample is taken after flushing at least three plumbing volumes. 2) First draw sampling: This sample is taken first in the morning before the tap in the premise has been used for other purposes. During the over-night stagnation period no water should be drawn from any outlet within the property. 3) Random daytime sampling: This is a sample taken at a random time of a working day directly from the tap in a property without previous flushing. Physical properties of the water samples, notably; Temperature (T), pH, Dissolved Oxygen (DO) and Electrical Conductivity (EC) were immediately measured at sampling stations using a portable digital pH meter (HACH HQ 40D). The samples were analyzed for Cu, Cd, Zn and Pb using an anodic stripping voltammetry method. Voltammetry is an electrochemistry method based on the study of current vs. potential relationships. This method play an important role in analytical chemistry with a wide range of applications, especially metal analysis and their speciation. The concentration of heavy metals in water samples, especially those from treatment plant (source water) and newer city neighborhoods with polypropylene service pipes are below the permissible limits set by WHO and ISIRI. In contrast, 75% of samples contaminated by cadmium and 60% of those contaminated with lead are belonged to the older districts of the city with lead alloyed service pipes. In the first draw sampling method, the concentrations of metal ions in water samples were much higher than their concentration in other sampling methods. This is more prominent in the older district of the city. This can be attributed to corrosion of old lead alloyed pipes due to sufficient stagnation of water in service pipes. The concentrations of metals are lowest using the fully flushed sampling method and highest in the first draw sampling. This further supports the fact that old lead alloyed service pipes are mainly responsible for the heavy metals contamination of water samples from the Zanjan City water distribution system.

    Keywords: Zanjan city, Drinking water, Water distribution system, Voltammetry method, Heavy metals
  • Elham Kadkhoda, Gholamabbas Fallah Ghalhari*, Mohammad Baaghideh, Seye Alireza Farid Hosseini Pages 27-38

    Although nature has the ability to deal with change, it cannot tolerate the growth of industries, deforestation and degradation of the environment. These huge and abrupt changes have caused to increasing the destruction of nature in recent decades, and increasing greenhouse gases. Ground water plays an important role in sustaining ecosystems and enabling human adaptation to climate variability and climate change. Groundwater resources are the largest store of fresh water in arid and semi-arid regions. In the areas where surface water resources are limited and inaccessible for people, groundwater can be considered as a secure resource. Climate change caused fluctuations in the ground water. Many wells dried up and some of them have lost their advantage due to the lack of available water. Climate change through changing climatic variables (including temperature, precipitation and evapotranspiration) directly affects surface water resources in many parts of the country. Besides, there have been many related problems such as drying up wells, reducing river flow, decreasing water quality, subsiding in lands, diminishing fresh water supplies and increasing salts in water. Climate change and its associated problems appear to be a serious challenge in the regions as Khorasan Razavi that 32 of 34 desert plains were declared prohibited. Due to cold and dry weather conditions and use of aquifers and wells as the main sources of water, Mashhad relies on groundwater as well as underground resources. The water resources of this plain are affected and threatened by changes in groundwater levels, temperature, rainfall, and frequent droughts. This research aims to study the groundwater level decline in Mashhad plain which is located in Khorasan Razavi province, northeastern of Iran. The study tries to conduct a comprehensive study through the analysis of monthly precipitations data acquired from 34 synoptic, climatology and rain-gauge stations, monthly discharge of 13 hydrometric stations, and 60 groundwater piezometric wells. It confirmed the normality of climatic data, using the Kolmogorov-Smirnov test. The research also used multivariable regression methods as well as HadCM3 climate model scenarios to model groundwater perspective of Mashhad’s plains and to predict future climate variables, respectively. To compare the output scale of the mentioned model with the required scale of climate change studies, the data of temperature and precipitation were downscaled for the two periods of 2015-2030 and 2046-2065, under three scenarios of A1B, A2 and B1 using the LARS-WG5.5 model. It later employs geographical weighted regression (GWR) to model the ground water level (as the dependent variable) with climatic parameters of temperature, precipitation, and evapotranspiration (as independent variables). Mashhad’s prospect of precipitation and temperature revealed a rainfall reduction for the cold season, its increase in the warm season, and at least one-degree increase compared to the base year. Modelling of groundwater level changes (using the parameters of rainfall, temperature and evapotranspiration) showed decline in groundwater levels in the range of at least 0.2 meters and maximum 0.7 meters. The research provides an intelligent simulation for fluctuations of groundwater using multiple regression models and the historical data of rainfall, temperature and evapotranspiration, which helps to estimate underground water level in the coming years. The results indicate a drop in the water level of all studied piezometric wells, under three climate change scenarios for future periods. The study concluded that the most important reason of water loss in Mashhad’s plains is the human overuse of groundwater. Fluctuations in groundwater assessment have shown that the highest annual fluctuations of groundwater were occurred in the southern part of Mashhad plain. Fluctuation assessments of surface water showed negative fluctuation in upstream and positive in downstream. These issues reflect the role of human factors in increasing the groundwater level in downstream and reducing the level in upstream. Modeling of groundwater level fluctuations with climate parameters (temperature, precipitation and evapotranspiration), using GWR and OLS models, represents superior of geographical weighted regression model compared with ordinary least squares models. Fitting weighting matrices to GWR model showed high accuracy of Gauss method than the other studied methods. The important issue that was obtained from simulations of Mashhad station is reducing the variance of rainfall in A1B emission scenario, indicating the absence of stable conditions in the future. The results of this research showed that the most important reason for the drop in Mashhad plain is overuse of groundwater.

    Keywords: climate change, Mashhad plain, Modelling water resources, groundwater
  • mina tajabadi, ali ziaei, kamran Davary*, azizallah izady Pages 39-50
    Introduction

    Groundwater is the most important water resources in Iran that provides majority of agricultural and urban demands. In recent years, recharge from natural and extended urban areas caused the water table in alluvial Bojnord aquifer to be increased. Transffering water from Karstic aquifers and Shirin Dareh dam intensified this problem specially in fine grain areas of the city. Supplying water from f alluvial aquifer from natural and urban areas, low thickness and discharge potential of alluvial and development of Bojnourd were caused enhancement in the absolute height of water table in the alluvial aquifer. Also in the plains such as Bojnourd plain that are urban uses, According to the mentioned problems, water supply is very important. Therefore, it is essential as much as possible, the current situation and future of Bojnourd alluvial aquifer are identified and management solutions are pursued to eliminate probable problem. The numerical model of groundwater flow can be used as a tool to test the effect of management decisions but usually lack or incomplete information of the hydraulic characteristics of the aquifer causes limitation of use of these models. Nowadays, in the all of the world many studies are ongoing about stratigraphy of aquifers in order to more understanding about the complicated condition in the water flow hydraulics. So it seems that understand of Bojnourd plain aquifer stratigraphy and a better estimation of the hydrodynamic coefficients can help to make decision appropriately to deal with the problems. The aim of this research was to make model of Bojnourd aquifer with emphasis on hydro-stratigraphy. Discuses: According to the variety of Bojnourd aquifer sediments, it cannot be assumed one-layer aquifer; so in order to reduce uncertainties, as well as developing, the conceptual model has been tried to identify natural effects that impact on groundwater system, especially stratigraphy of sediments are introduced to models. The effective factors include geological studies, geophysical sections, boundary of modeling, using of observational wells and determination of the recharge and discharge. In this study, to verify and judge models with different fifteen lithology cross section during aquifer using Rockworks software to obtain the appropriate layer of aquifer that eventually lead to more accurate estimation of three-dimensional lithology model. Rockworks software uses lateral Bending Horizontal method to interpolate lithology of wells log data. Then using three-dimensional model techniques in Rockworks16 software, the three-dimensional model of the aquifer lithology with all available data and information, i.e., logs and geophysical studies has been obtained. Three-dimensional models of geology are as subsurface three-dimensional representative that those can show spatial relations of logs lithology and lenses. Interpolation between the existing logs is not defined as the distance fillers and increase of boreholes in aquifer adds accuracy of these models. The results of three-dimensional models represent three-dimensional groundwater flow model of the aquifer system. The result of lithology modeling of aquifer is composed of four soil textures including of coarse grain, medium-grain, fine grain and very fine grain with four layers and with a thickness of 30m that was imported to version 1.7.10 of GMS software. Conclusion The model was run in steady state for October 1380. In the first step, the initial model coefficients were calculated. After running the model in steady state, the mean square error was 2.77 m. In the next step, the results were better with changes in the soil hydraulic conductivity values and the mean square error was 0.794m after calibration. Heterogeneity and lenses in the aquifer system caused changes in hydraulic conductivities of coarse to very fine-grained sediment, so the identification of aggregation and different genders, lithology of the aquifer with higher accuracy is achieved and consequently, the hydrodynamic coefficients (k,s) will be estimated more precisely. So considering that the aquifer materials are heterogeneity, the hydraulic conductivity values were obtained as 8.1, 6.7, 1.9 and 0.4 for soil textures of Coarse grain, medium grain, fine grain and very fine grain, respectively. Totally Changes of water level were between 1020 to 1080 meter and in the first layer; the northern and eastern parts of aquifer were dry. According to flow budget of the aquifer in one layer model was obtained with acceptable accuracy in multi-layer models, to establish flow budget in accordance with the single-layer model. The calculated flow budget by the model showed that the aquifer layer was in balance with the amount of input and output approximately.

    Keywords: Lithology modeling, Bojnourd, GMS, Hydrodynamiccoefficients, Rockworks
  • Dr M.A. Shahrokhnia*, Ladan Jokar Pages 51-62
    Introduction

    Water is a valuable asset for agriculture in arid and semi arid regions, worldwide. Reducing water leaks from the irrigation canals will save more water and leads to economic agriculture. Previous studies showed the importance of seepage assessmemt in irrigation canals. Assessment of seepage can be done by practical, theoritical and empirical methods. The review of literature reveals that the direct or practical methods can be more trustable comparing to theoretical or empirical methods or models. Ponding and inflow-outflow methods were widely used as direct or practical methods for seepage evaluation in irrigation canals. Use of empirical seepage formulas needs less cost and time comparing to other type of methods. However, the empirical models have different estimation accuracy and needs to be evaluated more. It is recommended in literature that the empirical models should be calibrated for a specific region before use. Simple empirical models have an estimation error about 15 percent due to direct measured values.

    Methods

    In present study, seepage was measured and compared in three irrigation earth canals in Darab plain using inflow-outflow method and various empirical formulas. These three canals named Hasanabad Canal, Mansuriyeh Canal, and Janatshahr Canal. The soil texture class of these three canals is Loam, Clay Loam and Sandy Loam, respectively. The canal flow velocity was measured using Valeport flow meter in the beginning and the end of three distances of 200 meters along each canal. The discharges were computed by multiplying the mean velocities and flow areas. Difference between the inflow and outflow discharge shows the canal seepage in the selected reaches. The Ingham, Davis-Wilson, Molesworth-Yennidumia, Affengendon, Moritz, Misra, Garg, Indian Punjab, Egyptian Irrigation Department empirical models were used for the study. Mean absolute error, root mean square error, normalized root mean square error, coefficient of variation of root mean square error, and χ2 test were used for the comparison of estimated and measured values. These empirical formulas were calibrated and validated due to the inflow-outflow method.

    Results

    Results showed that the Moritz and Affengendon formulas with mean absolute error of 49% and 1445% percent had the least and most difference with inflow-outflow method before calibration. The error of estimation of the other formulas was about 125%. The highest estimated seepage was in the Affengendon formula, while the lowest was in the Ingham and Indian Punjab formulas. Comparison of estimated seepage values using t-test shows that the difference between the empirical seepage formulas is significant at 95% confidence probability. However, the difference between Moritz and inflow-outflow methods, Ingham and Molesworth-Yennidumia, Ingham and Indian Punjab, Molesworth-Yennidumia and Indian Punjab formula, Garg and Davis-Wilson formula was not significant at 95% confidence probability. The seepage estimation error of uncalibrated Ingham formula was about 95%, while for calibrated formula was less than 11 percent. The error of seepage estimation using uncalibrated Moritz and Molesworth-Yennidumia formulas were about 52 and 96 percent. This error for the uncalibrated Indian Punjab, Affengendon, Egyptian irrigation department, Garg and Misra formulas were about 95, 1220, 90, 92 and 68 percent, respectively. Results also showed that the error of calibrated Ingham, Molesworth-Yenidumia, Moritz, Davis-Wilson and Affengendon models, was about 7, 8, 9, 10, 10 percent comparing to inflow-outflow method, respectively. After these five formulas, the error of estimation of Garg, Egyptian, Misra, and Indian formulas were 17, 18, 20 and 20 percent, respectively. In order to validate the evaluated empirical formulas, some statistical parameters such as root mean square error, normalized root mean square error, coefficient of variation of root mean square error, and χ2 test were used. Results shows that the evaluated empirical formulas can be sorted from the better validated to the worse validated as Ingham, Molesworth-Yennidumia, Davis-Wilson, Moritz, Affengendon, Garg, Egyptian Irrigation Department, Misra and Indian Punjab. The χ2 values of the evaluated empirical formulas were 0.077 for Ingham formula to 0.757 for Misra formula. It can be concluded from this research that the uncalibrated empirical seepage formulas had significant difference to the inflow-outflow direct method. However, all of the calibrated formulas had a mean relative error less than 20 percent comparing to inflow-outflow method. Ingham formula was the best formula due to less calibration error. Moritz and Misra formulas had the best and worst validation condition in the study, respectively.

    Keywords: Seepage, empirical formula, Darab, irrigation canal
  • Fouad Kilanehei*, hamid reza monemi, amir mahjoob Pages 63-74

    Levees are man-made embankments built to prevent rivers from overflowing their banks. A levee is a naturally elongated ridge or artificially constructed fill or wall that regulates the water level. It is usually earthen and often parallel to the course of a river in its floodplain or along low-lying coastlines. The levee construction is a common and very old method of river flood control recently used considerably as an engineering operation to reduce or prevent the detrimental effects of floodwaters. It can be used either alone or together with other methods to minimize the floodwater damage. Engineered earthen levees are of three general types: compact, semi-compact, and uncompact; the former are usually and traditionally used in areas of high property values, high populations, high land use, or in controlled compaction, steep-sloped embankments utilized on good foundation conditions during construction. The semi-compact or uncompact levees are generally used in low value, poor foundation areas or those with high rainfall during the construction season. Compared to other floodwater control methods, levees are more efficient because they are not only quite cost-effective, but also provide more factor of safety for slope stability. Artificial levees are aimed at preventing the adjoining countryside flooding and slowing the waterways' natural course changes to provide reliable shipping lanes for maritime commerce over time; they also confine the river flow causing higher and faster water flow. Levee construction materials should be coarse enough to withstand the erosion caused by the flowing water, their shear strength should be enough to satisfy the levee's slope stability, and they should be adequately impermeable meaning that they should also contain fine aggregates to prevent the extra seepage that has undesirable effects on the levee's slope stability; therefore, making specific arrangements to reduce repercussions deems necessary. Massive constructions that require large amounts of materials need to use the available on-site materials to reduce the transportation distance and hence the project construction cost; using on-site materials is a significant advantage the levee construction enjoys. As mentioned before, since the levee construction needs both coarse- and fine-grained materials to reduce permeability, the best choice can be the coarse-grained soil containing clay; therefore, both GC (clayey gravel) and SC (clayey sand) soil types take priority over any other types. Hence, evaluating the amount of the soil fine aggregates and the effects of compaction percentage on the permeability coefficient and on other strength parameters to meet the economic, speed, and time requirements of the levee construction is quite important. This research studies the effects of compaction percentage and the amount of fine aggregates on the SC soil permeability and on the steady and unsteady seepage flow through levees. Accordingly, three levee samples A, B, and C (from Mehran River borrow area) with respectively 12.8, 20, and 28.4% fine aggregates and 60, 70, 85, and 100% compaction have been selected to carry out the permeability tests. Results of tests with different compaction and fine aggregate percentages showed that an increase in the percent compaction of each sample (from 60 to 100, 70 to 100, and 85 to 100) decreased the permeability coefficient 25, 14.3, and 8.91 times, respectively. At every compaction percentage, sample A's permeability coefficient was 1.2 times that of sample B and 1.69 times that of sample C and that of sample B was 1.41 times that of sample C. Next, using the numerical modeling, both the flow rate (in the steady state) and phreatic line (in the unsteady state) through the levee were studied with different compaction percentages and the results showed that in simulating the unsteady seepage through the levee the phreatic line did not intersect the downstream slope and was significantly far from it. The results of this research can be used to either design or construction of the levee; furthermore, it can used to analyze the effect of the soil compaction percent on permeability parameter during construction of levees.

    Keywords: levee, steady, unsteady flow, permeability coefficient, compaction percentage, fine grained percentage, numerical modeling
  • using Bacterial Foraging Algorithm (BFO) to estimate the coefficients of uniformity of water distribution in sprinkler irrigation
    Elahe hosseinian, Hassan torabi Pages 75-84

    One of the important parameters in agriculture, regarding to assessing irrigation systems, is water distribution uniformity coefficient (CU) in sprinkler irrigation. The first study of sprinkler irrigation uniformity was executed by Christiansen (1942) in California that led to introduce the Christiansen uniformity coefficient. Nowadays, it is very common to use Christiansen uniformity coefficient in sprinkler irrigation systems. Many researchers have investigated water distribution uniformity coefficient in solid set sprinkler systems. While, other researchers such as Hart and Reynolds (1965), Karmeli (1997), Vories and Bernuth (1986), Dabbous (1962), Heerman (1983), Keller and Bliesner (1990), Carrion et al. (2001), Montero et al. (2003) and Bavi et al. (2006) have investigated different aspects of water distribution uniformity coefficient. A sprinkler water distribution pattern depends on the system design parameters such as: the sprinkler spacing, operating pressure, nozzle diameter, as well as environmental variables such as: wind speed and direction. The sprinkler irrigation distribution patterns have been characterized by various statistical uniformity coefficients. Also, various coefficients of uniformity (CUs) have been developed over the past decades. CU amount of water sprinkler operating depends on different pressure heads (P), riser height (RH), distance between sprinklers on lateral pipes (Sl) and the distance between lateral pipes (Sm). The best combination of the above parameters for maximum CU is still unknown for applicators. Many researches, such as Hezar Jaribi et al. (2009), have been done to estimate various relationships using different algorithms. Different researchers have used various concepts to express the coefficients of uniformity; hence the equations lead to different results in the expression of the distributed water uniformity in the same fields. This paper evaluates different uniformity coefficients, using Bacterial Foraging Algorithm (BFO), to propose the best and optimized equation for CU. Generally, the task is to optimize certain properties of a system by pertinently choosing the system parameters. So, in this study, CU has been estimated by Bacterial Foraging Algorithm, and an equation was proposed with the optimized coefficients for CU. The field experiments were conducted on a farmland located in Hashem Abad Agricultural Research Station of Gorgan Cotton Research Institute, about 11 kilometers northwest from Gorgan, Iran. In this area, the lands were irrigated by solid set sprinkler irrigation systems. The sprinkler uniformity tests were conducted using rain-gauge for measuring uniformity coefficients. CU quantities of zb model sprinkler (made in Iran) were considered with three different pressure heads (2.5, 3 and 3.5 atm), two riser heads (60 and 100 cm) and seven sprinkler arrangements (Sl×Sm including: 9×12, 9×15, 12×12, 15×12, 12×18, 15×15, 15×18m). In this study nonlinear equation uniformity coefficients in sprinkler irrigation have been optimized by using Bacterial Foraging Algorithm (BFO). Typically, the BFO consists of four main mechanisms including chemotaxis, swarming, reproduction, and elimination-dispersal event. Totally, the algorithm was run more than 70 times for various conditions and obtained the best case. While optimizing CU Equation by Bacterial Foraging Algorithm (BFO), The best results obtained in S, Nc, Nre, Ned, and C(i) which were equal to 24, 500, 8, 8 and 0.01, respectively. The outcome of this optimization is the following equation which was derived to estimate the Christiansen uniformity coefficient (based on the specified working pressure of the sprinkler, sprinkler height, distance between sprinklers on the pipes side and distance between side pipes). To evaluate the proposed optimal equation, it was used to estimate Christiansen uniformity coefficient distribution of the 70% of the experimental data. Then, the model obtained from 70% of the data was verified with remaining 30% of the experimental data. The estimated Christiansen uniformity coefficient distribution (obtained from the equation) revealed high accuracy, compared with the 30% and 70% of the observed data. Result showed that the maximum absolute error between the outcomes of this algorithm with the measured values was less than 3%. This error was based on using 30% of the data. Also, the root-mean square error (RMSE) was equal to 2.13. Therefore, it is revealed that this algorithm has high accuracy in estimating water distribution uniformity coefficient. Generally, it can be said that Bacterial Foraging Algorithm is more acceptable for optimizing nonlinear functions, comparing with other algorithms such as genetic and differential evolution algorithm. Also, it has much higher rate of convergence, whereas does not make local optimal problems.

    Keywords: Uniformity Coefficient, Water Distribution, Sprinkler Irrigation, Bacterial Foraging Algorithm (BFO)
  • mohammad hooshmand*, Prof. Saeed Boroomand nasab, mohammad albaji, naser alam zadeh ansari Pages 85-94

    Deficit irrigation is the strategy used to produce a crop with maximum income and profits. This method has attracted attentions due to the intensification of the water crisis and population growth. Basinger and Hellman (2006) suggested that deficit irrigation increases the water use efficiency by 72%, but it has little effect on reducing the amount of the product. Negaz et al. (2013) experimented the efficiency of optimum water use of lettuce, in different irrigation regimes (30, 60 and 100% of plant water requirement), in Tunisia. The results showed that the highest water use efficiency was related to 30% water requirement and the lowest was 100% water requirement with 34.3 and 14 kg/m3, respectively. Haghighi (2008) compared the PRD (Partial root zone drying) irrigation method and conventional irrigation on greenhouse tomato growth and concluded that PRD treatment increased the water use efficiency of the plant and increased the total soluble solids. While, no significant difference was observed between the two treatments in the number of fruit, color and fresh and dry weight of root. On the contrary, PRD reduced the dry weight of the shoot and the weight of the fruit. Also, the rate of handling and distribution of red fruit was higher in PRD treatment. This study were investigated the effect of regulated deficit irrigation (RDI) and PRD on tomato, under hydroponic culture conditions. The treatments of experiment consisted of five treatments: RDI irrigation at 85 and 70% of plant water requirement and PRD irrigation at 85 and 70% of the plant water requirement, and control treatment. The experiments were carried out in a completely randomized design with four replications. The water requirement of the plant was determined by the evaporation rate from class A evaporation pan (located in the greenhouse) and multiplying it at the plant shadow level. To feed the plants, Resh nutrient solution (2005), which contains macro and micro nutrients for plant growth, was used. For preparing of solution, urban drinking water was used with EC=1.8 mS/cm. The leaf area was measured every two weeks by a ruler. After applying the treatments, the greenhouse tomato product was manually harvested in 5 times. The number of harvested fruits only consisted of fruits that were fully grown and ready to be harvested. According, every 2 weeks, the fruits were counted, harvested and weighted. After the end of the growth period, the fresh and dry weight of root, fresh and dry weight of leaf, leaf water content, leaf area, fresh and dry weight of stem and biomass and dry weight of plant were measured. Also, leaf area index (LAI), special leaf area (SLA), leaf area ratio (LAR), harvest index, water use efficiency and efficiency of biomass water use were calculated. The results showed that different methods and levels of deficit irrigation had significant effects on fresh and dry weight of root, fresh and dry weight of stem, plant dry weight, fruit weight and water use efficiency. But, the levels of applied water did not significantly affect fresh and dry weight of leaf, leaf water content, leaf area, leaf area index, special leaf area, leaf area ratio, biomass weight and harvest index. The results showed that the plant with irrigation application of 85% of plant water requirement showed different results in fruit weight index and water use efficiency, in comparison with the control treatment. Deficit irrigation of PRD treatment in the weight of fruit increased by 3.5% and water use efficiency increased to 22 percent, compared with control treatment (2572.5 g and 16.07 kg/m3, respectively). But, RDI treatment in fruit weight decreases by 20% and reduces water use efficiency by 5.5% compared with control treatment (1997.8 g and 12.48 kg/m3, respectively).With reducing applied water to 70% of plant water requirement, the behavior of the plant was different, and RDI treatment showed a lower reduction for the fruit weight index and water use efficiency than PRD treatment. Accordingly, the RDI treatment in fruit weight decreased by 35% and water use efficiency decreased by 7% (1614.2 g and 12.24 Kg/m3, respectively). While, PRD reduced 52% in fruit weight and decreased 31% of water use efficiency (1189.5 g and 9.02 Kg/m3, respectively). Eventually, PRD treatment with 85% of plant water requirement was selected as the best method for hydroponic culture of tomato in greenhouse.

    Keywords: water use efficiency, partial root zone drying, deficit irrigation, tomato, Soilless culture
  • Keiwan Naderi, Ataallhah Nadiri*, Asghar Asgari Moghaddam, Mehdi Kord Pages 95-106

    In the recent decades, due to the complexity and nonlinearity of aquifers, artificial intelligence (AI) models have been extensively used in aquifer modeling. The purpose of this research is GWL predicting using hybrid of Self Organizing Map (SOM)-clustering method with Artificial Intelligence (AI) approaches, including support vector machine (SVM) and fuzzy logic (FL). The basic concept and theory of SVM was introduced by Vapnik (1995). The SVM implement the structural risk minimization (SRM) principle. The most important concept of SVM is minimizing an upper bound to the generalization error, instead of minimizing the training error. SVM has two outstanding of excellent generalization capability, and sparse representation. Zadeh (1965) introduced the fuzzy sets. A fuzzy system includes three parts: 1. Fuzzification, the degree of membership in a fuzzy set is defined through a membership function; 2. Fuzzy rule, A fuzzy rule-based model operates on an if-then principle; 3. Defuzzification. Basic FL models and clustering techniques have been combined to provide objective FL modelling techniques, but there are variations with respect to the type of their output membership function and the implication methods. As an efficient mathematical tool, SOM may be used to visualize a high-dimensional data set (Nourani et al, 2016). SOMs reduce data dimensions and show similar patterns. Each SOM network typically includes one input and Kohonen layer. This method may reduce the aquifer's heterogeneity due to unsupervised classification of the aquifers. Based on availability of data, 10 observation wells (OW1-OW10) in the study area were selected for predicting groundwater level. The monthly groundwater level at previous time (GWL_(t_0-1)), Monthly temperature at current time (T_(t_0 )), Monthly precipitation at current time (P_(t_0 )) and monthly discharge of the Zola river at current time (Q_(t_0 )) were used as inputs of models. All data were monthly, of 15 years (2001-2016). 80% of data were used for training and 20% for test step. In order to examine the effectiveness of the models in predicting GWL, the performance measure was quantified for all models using three indices: Root Mean Squared Error (RMSE), Coefficient of determination (r2) and Nash-Sutcliffe Efficiency (NSE). The Salmas plain with an area about 550 km2, located at north of West Azarbaijan province, northwest of Iran. This area is a part of the Urmia Lake catchment and considered as a semi-arid and cold zone, with average annual temperature of 10.36 °C. Of the 27 observation wells (OW) in the aquifer of Salmas plain, 10 of them were selected to predict the monthly groundwater level. Due to hydrogeological and morphological heterogeneous nature of this aquifer, the SOM-clustering method was used to classify the observation wells. This method produces three groups, labelled as G1, G2 and G3. Sugeno Fuzzy Logic (SFL) models were implemented for each of the three groups of observation wells, using the Subtractive Clustering (SC) technique by systematically increasing the cluster radius from 0 to 1. The input and output clusters were created using the Gaussian and linear membership function, respectively. Least Squares-SVM (LSSVM) type was applied to predict GWL. Selecting suitable kernel function and optimized value of kernel (γ) and regularization (C) parameters is important step in implementing SVM. The optimized value of γ and C were determined based on minimizing RMSE. The SFL and LSSVM models were built in three groups for predicting GWL at OW1-OW10 of the study area using training data. The three performance measures of RMSE, r2 and NSE for each of two models (SOM-SFL and SOM-LSSVM) at each of observation wells were calculated. The performance of SOM-SFL and SOM-LSSVM models during the testing was evaluated using the three performance measures for training the models and compared with the results obtained. This research investigated the hybrids of SOM-clustering method with SFL and LSSVM approaches for predicting groundwater level. Performance measures of these models indicate that their results of two hybrid models (SOM-SFL and SOM-LSSVM) are acceptable. In group one (G1) of observation wells (OW1 and OW7), SOM-LSSVM performs better than SOM-SFL. In OW2, OW6 and OW9, obtained results show that SOM-SFL model has better performance. The proposed hybrid models in this research (SOM-SFL and SOM-LSSVM) could successfully be used in predicting GWL. Combine the results of two models and using of multiple models can improve the final results.

    Keywords: null, Fuzzy logic, Support vector machine, Self organizing map, Groundwater level
  • ebrahim mohammadi soleimani*, majied Ahmadian, mohsen shokat fadaeiali, ali Keramarzadeh, Abolfazl Mahmoodi Pages 107-116

    The Jiroft Plain Basin is part of the Jazmurian Waters Basin, located in the south of Iran, Kerman province. The uncontrolled extraction of groundwater from the aquifer of the forbidden Jiroft plain has caused the aquifer's water level to fall, which could seriously threaten the agricultural economy of the region. If this action is not considered seriously, this plain will not only exacerbate environmental impacts in the future, but will also face economic and social problems. The purpose of this paper is to identify the status of Jiroft Plain Aquifer in recent decade and compared the cost of water extracting from wells in two types of water extraction technology: diesel and electric pumps. Initially, based on available statistics and information, which collected from Iran Water Resources Management Company, Kerman Regional Water Company and Jiroft District Water Company, the status of the groundwater Aquifer in Jiroft plain has been investigated. Then the cost of water pumping from wells with electric and diesel water removal technology was compared. To achieving the study purposes, questionnaires was collected from beneficiaries of Jiroft plain agricultural water wells in the crop year 2014-2015.The sample size was determined by the simple random sampling method. In the meanwhile, the data of the questionnaire include: crops production cost in 2015-2016, how to use water wells, energy consumption, and cost of energy and pump maintenance costs. To sum, 227 questionnaires were collected that 202 cases of them used electro pump technology, and 25 cases used diesel pumps for withdrawing water from wells. The results showed that average depth of electric and diesel wells were 101 and 55 meters, and their average discharge was 25 and 15 liters per second, respectively. It can be seen that the electric pump, in comparison with the diesel pump, results in more drainage and further increase in annual drop of groundwater level. Whereas, its energy cost is less than diesel pump. Also, the results showed that the cost of water extraction per cubic meter of water with electro pumps and diesel pumps are 169 and 365 IRR, respectively. It means that extraction cost with electro pump is about half of diesel pump cost. So, if we change the technology of water extraction from diesel to electro pumps, we can save 1.525.670 and 3815920 IRR on cultivating cost for one hectare of wheat and orange, respectively. The wells with electro pump technology, in comparison with wells with diesel engine motors, have more average depth and average discharge rates. From working hours' side, electric pump is more than diesel pumps. Therefore, by using electric pumps, more water will extracted from groundwater resource and eventually decrease the level of water aquifer. Although the converting pump type policy from a diesel to electric pump has been supported by the government in recent years and has been included subsidized facilities, it has caused negative effects. This policy could save up to 50 percent of pumping and pump maintenance costs for agricultural operators and consequently reduced the cost of production but the lack of some policies by the government such as pricing, tariff and incentive policies to control the volume of groundwater extraction has led to increase a pressure on groundwater resources. Farmers who have economic logic accepts the fixed costs of changing diesel pump to electric pump to reduce production costs in the long run and exploit the benefits of more water extraction, but the policy makers have not taken any action for maintaing the groundwater resources of the plain. Therefore, the fallowing approaches are suggested: implementing policies to control the volume of water extraction to prevent the continuation of the process of discharging strategic reserves, contributing to the equilibrium of the aquifer's plain water level, reducing the discharge rate of the exploitation at the request for change of diesel pump to electric pump

    Keywords: Jiroft Plain, extraction cost, Electric pump, Aquifer
  • Ehsan Tavakoli*, Behzad Ghorbani, Alireza Tavakoli Pages 117-126

    Introduction Considering the vital importance of water in arid and semi-arid regions like Iran, conservation and optimal use of water resources is necessary. In this regard, increasing conveyance efficiency and reducing water losses in distribution canals are very imperative. Low water conveyance efficiency in distribution canals is mainly due to seepage losses in channels. However, since infiltration and seepage cause groundwater recharge, it is sometimes beneficial. Reviewing the literature revealed that some specialists believe lining channels is not justified, technically and economically. Other experts do not reject lining at all, however, suggested that since seepage could help groundwater recharge indirectly, in regions which there is no ponding problem, channel lining should justify from the economic point of view. Additionally, another group of researchers found that although construction costs of lining seems very high, considering its long term benefits for countries with vital need to water in future, such as Pakistan and Iran, is economic. Meanwhile, according to some studies, concrete lining is not economically justified. Based on numerous different and sometimes opposite opinions regarding economic justification of lining, it seems necessary to investigate this issue on regional scale. Thus, the current study aimed at economic analysis of infiltrating water from unlined canal to groundwater and pumping again through wells to surface, in comparison with lining canals and not allowing to seep. Method In order to do this research, the concrete canal of modern Irrigation and Drainage network of Gandoman and Boldaji, Borujen city, Chaharmahal and Bakhtiari province, with 1.3 m width, 1.8 m depth and 6.5 m top width, was chosen as prototype. In order to analyze the lining, this channel was compared with an earth canal, having the same dimensions. Soil texture was determined using hydrometer method, which was obtained as loam that was constant to the depth of water table (6.79 m from soil surface). In order to estimate the amount of seepage in the earth channel, using physical modelling and dimensional similitude relations and considering 0.13 as scale ratio, dimensions and discharges of lined canal have converted to laboratory dimensions at soil mechanics lab of Shahrekord University. Lining lifetime was selected10, 20 and 40 years, and the interest rates were 12, 15 and 18 percent. Results Based on the results, the measured seepage loss in experimental flume of laboratory for the unlined and lined canal was 26 and 11 %, respectively. According to calculations, the price of groundwater in the study region is nearly 0.24 cents per cubic meter. Bearing in mind the low depth of groundwater in the study area (6.79 m), this small value in comparison with the price of surface water (0.31 cents per cubic meter), will justify. According to ‘base unit price index for irrigation and drainage works’, the costs of earth and lined canal construction with length 30000, top width 6.5 and bottom width 1.3 m, was calculated and obtained as 10768 and 91060 M.Rials respectively. It has been noticeable that for construction of both type of canals, half of cutting practices have considered in stony lands and the remaining in earth lands. Furthermore, renovation and maintenance costs for unlined channel were taken into consideration, which have been applied from year 1 to 10, 20, and 40 years. These costs have increased by 15% increase per year (according to the inflation rate). Results showed that increasing the interest rate from 12 to 18% has been resulted in decreasing both NPV and B/C values (except for B/C in concrete-lined canal, 40 years). On the other hand, increasing the lifetime of lining from 10 to 40 (constant interest rate), the NPV and B/C values were increased at first and then were decreased. Investigating the calculations showed that after 30 years, with maximizing the maintenance costs of lined canal, its costs exceed its benefits. Therefore, lining canal with the mentioned properties will not be economical after 30 years. Consequently, with all lifetime values, the earth canal is more economic than the lined one, considering both economic indices and for all interest rates. Therefore, it could be concluded that when the water table depth is 6/79 m and it is possible to pumpage the infiltrated water from well (while the canal is unlined with a loam soil), which are the properties of Borujen region in the current study, lining with concrete is not justified economically.

    Keywords: earth canal, Gandoman, Boldaji irrigation, drainage network, lined canal, physical modelling
  • Assessment of changes in surface water and groundwater interactions in the Leningrad Sub-basin
    Aliasghar Hashemi, Hosein Samadi, Rouhallah Fatahi Pages 127-136

    In this study, water exchange in normal and severe drought conditions was also investigated. Based on the historical time series of zayanderood stream flow in Sadtanzimi, the water years 1373-1374 and 1379-1380 were selected as normal year and severe drought condition, respectively. By derived equations, outflows of three reaches were obtained under normal and drought condition. Based on the results, in normal condition net exchange of surface water was negative in three reaches, and only a small amount of 5 million cubic meters per year has been added to surface water in the second period. The results in normal year showed that surface water was fed by groundwater in the first reach and in the other two reaches fed groundwater. Compared to the normal water year, significant changes were observed in the exchange of surface water with groundwater and atmosphere in severe drought conditions. In the first reach, surface water gain by groundwater was observed, which this increase is 17% of outflow of this reach during drought conditions. During the drought, only the first period has not faced with shortage. The flows and water exchange in this situation have been such that the observed outflow of the three studied reaches is reduced by half the inflows. Surface water of the first reach has net gain in drought conditions. While under normal conditions, this interval was purely water withdrawal. Duo to the lack of accurate data on withdrawals and return flow, these components of the surface water balance were considered as annual average. However, the obtained results and their comparison with the data and information in the previous studies showed that the proposed method is a suitable toll for assessing the exchange of surface water with groundwater. Therefore, in future studies it is suggested studying this method with more accurate data on exploitation and return flow. Keywords: Surface water and Groundwater Interaction, Streamflow, Mass balance, River reac

    Keywords: Surface water, Groundwater Interaction, Stream flow, Mass balance, River reach
  • Mehrdad Nowroozi*, Mokhtar Zolfi Bavariani Pages 137-146

    In recent decades, the use of saline water in agricultural production has increased dramatically due to the reduction of fresh water resources. But, safe use of saline water requires proper irrigation management. This experiment was carried out to study the effects of water salinity on yield, water use efficiency and fruit quality of drip irrigated tomatoes in southern Iran (Bushehr) with arid and semi-arid weather during one cropping season (2010-2011). The experiment was designed as split plot in a randomized complete block design (RCBD) with four levels of water salinity (1.1, 3.7, 5.5 and 7.5 dS.m-1) and three levels of irrigation intervals (2, 4 and 7 days) with three replications. According to the results, with increasing irrigation interval from 2 to 7 days, the mean values of crop yield (Y), irrigation water use efficiency (IWUE) and fruit weight (FW) decreased by 20, 19 and 26% respectively. Also, with increasing salinity of irrigation water from 1.1 dS.m-1 to 7.5 dS.m-1, these values decreased by 33, 39 and 32% respectively. In general, under climatic conditions and soil characteristics of the experiment site, yield loss due to water salinity was far lower than that reported in FAO No. 29 paper (Ayers and Westcott, 1985). Also, with increasing irrigation interval and salinity of water, fruit quality increased in terms of the amount of soluble solids (TSS).

    Keywords: Drip, Tape Irrigation, Irrigation interval, Irrigation water salinity, Salt leaching, Water use efficiency
  • faride ansari samany*, seyed hasan Tabatabaei, fariborz abbasi, ebrahim alaiee Pages 147-160

    Limited water resources will be available if the quality is desirable today, by entrance of extensive industrial activities and the use of fertilizers in agriculture, the most important source of human life is in dangerous. According to researchers result, groundwater contamination is often due to poisoning wastewater from industries or from wastewater reservoir resources, one of the most important pollutants is nitrate. Nitrate in nature can be exchange to nitrogen or other forms by microbial activity. There are various methods for removing nitrate from water those most commonly using denitrification substrates. It has been proposed to create a wall of denitrification as a buffer against nitrate contaminated streams as a suitable way to prevent the entering of nitrate into groundwater resources and then surface water resources. In this research, tried to study the effect of nitrification using denitrification substrates that containing a mixture of soil and four carbon sources of liquid including glucose, acetate, ethanol and methanol. In this research, a Plexiglas column was used as a pillar of Marriott and water source and a porous media column filled with soil with a loamy clay texture of 50 cm length and 10 cm in diameter. Potassium nitrate salt was used to make a concentration of 100 mg / L nitrate solution. This study was carried out in two ratios of 1.5 and 3.5 C / N, and the concentration of nitrate was measured until when the pore volume reach to 10 and also concentration of nitrate output was stabilized. This research was carried out at the research laboratory of the Water Engineering Department of Shahrekord University. After about 250 hours from the start of the biological removal process, it was observed that the concentration of output nitrate was almost constant and there is not much change. This phenomenon may be due to the growth of bacteria because of the favorable growth conditions at the beginning of the experiment and the optimal separation of nitrate in a process and, finally, the lack of one of the factors affecting growth due to the maximum growth of bacteria. It is clear that at the end of the experiments and after the concentration of nitrate output from the column was fixed, green algae were observed in parts of the absorption column due to bacterial growth and massification. The removal efficiency of nitrate by glucose, acetate, ethanol and methanol was 97.83%, 97%, 98.66% and 99% respectively, and so methanol had the most efficiency in nitrate removal. Methanol, with 99% removal efficiency, can easily remove nitrate to a concentration of 100 mg / L at groundwater reduce to 2.1 mg per liter. Methanol with 131,000 bacteria had the highest bacterial growth rate in the C / N ratio of 3.5. In fact, by increasing the concentration of carbon, the growth rate of the bacteria increased and the concentration of nitrate decreased. In statistical analysis, both carbon-to-nitrogen ratios showed significant differences in carbon-nitrogen ratios other than glucose-acetate, with a significant difference in the mean carbon concentration. Also a paired test between different concentrations of a carbon source showed that there is a significant correlation between concentrations of 1.5 and 3.5 for each carbon source.

    Keywords: Bacteria, Efficiency Nitrates, Biological, Pollution, Removal rate
  • Paria Nasimi *, Hamidreza Motaghian, Ahmad Karimi Pages 161-171
    Introduction

    Soil organic matter plays an important role in improving physical, chemical, and biological properties of soil in agriculture. Biochar is a carbon-rich organic material that produced by pyrolysis of biomass under oxygen limited conditions and it improves the physical and chemical properties of soils. In recent years, biochar application in soil has been considered as a desirable way to improve physical conditions and increase soil moisture storage capacity. Achieving any of the above objectives depends on the physical and chemical structure of the biochar and its application to the soil.The main objective of this paper was to evaluate the effects of biochar, produced from date palm’s leaves, on the physical properties and hydrological behavior of a sandy clay loam soil by carrying out under greenhouse conditions.

    Methods

    For this aim, Pyrolysis at 400 degree of centigrade at 2 hour in an electric furnace biochars was obtained. Biochars were in powdered form and evenly added to soil (air-dried and passed through a 4 mm sieve) and incubated for 2 months. Therefor with determination of soil moisture content at field capacity, one, three, six and nine months after mixture soil and biochar, were measured hydraulic conductivity (kS) by taking soil samples from the pots. By measuring gravimetric water content at saturation percentage (SP), field capacity (FC) and permanent wilting point (PWP), plant available water content (PAWC) and relative field capacity (RFC) calculated. The Factorial experiment was conducted in a completely randomized design with two factors. The factors of this experiment was including amendment (palm’s leaves and biochar), application level (0, 0.5, 1, and 2% w/w), and time (1, 3, 6, and 9 month incubation).The treatments in this experiment were zero (B0), 0.5 (B1), 1 (B2) and 2% (B3) of biochar and zero (control) (D0), 0.5 (D1), 1 (D2) and 2% (D3) of palm leaves (zero, 18, 36 and 72 ton/ha, respectively) in three replications. Biochar were in powdered form and evenly added to soil (air-dried and passed through a 4 mm sieve) and incubated for 2 months.

    Results

    The results showed a significant difference (P <0.01) between treatments. The effects of soil conditioner on relative field capacity (RFC), permanent wilting point (θPWP) and plant available water content (PAWC) and the effect of application levels on all soil moisture coefficients were significant (P <0.01) and increased these coefficients. The results showed that with increasing palm’s leaves amount, saturation kS of soil is increasing and there is a significant difference (P <0.01) between treatments. The results showed that application of biochar and date palm’s leaves enhanced soil kS. Increasing palm’s leaves from 0.5, 1 and 2 percent w/w (18, 36 and 72 ton ha-1) compared to control increased kS by 24.2, 17.7, and 74.3% respectively. Increasing biochar from 18 to 72 ton ha-1 compared to control increased kS by 29.4 and 41.4 % respectively. The results indicate that date palm leaves have a higher effect on θFC than it is biochar. The results showed that adding of palm’s leaves from 0.5, 1 and 2 % w/w compared to control increased θFC by 12, 11.3 and 12.4 percent, and biochar application increased by 10.3, 9.2 and 8.4 percent in field capacity respectively. Also the results showed that the adding of palm’s leaves from 0.5, 1 and 2 % w/w compared to control increased θPWP by 15.7, 12 and 10 percent, and biochar application increased by 9, 5.6 and 12.6% θPWP respectively. The results showed that the addition of 1% w/w biochar after 9 months and adding 2% w/w of date palm leaves after 6 months produced the highest increase PAWC. The effect of biochar on PAWC indicates that there is a dramatic effect compared with the control, which can be attributed to the extracted surface and the increase of the micro porous pores, which increased water storage. Soil moisture behavior in the high matric suction is under the control of soil texture and its fine pores, but in the low suction it is under the control of the soil structure and its large porosity. There is a significant difference (P <0.01) between the short and long term effect of date palm leaves and biochar on hydraulic conductivity. The effect of biochar supplemental in long-term was more than the effect of palm leaves on increasing kS, while in the short term, the effect of date palm leaves was more than the effect of biochar on increasing kS. The interaction effects between time, type of soil conditioners (biochar and date palm’s leaves) and application levels on PAWC and θPWP were significant (P <0.01) and also (RFC were significant (P <0.05) but their effects on the θFC were not significant. The results revealed that biochar application is considered one of the best methods for soil management and improvement, which increased soil constant organic matter and improve soil physical properties. It is concluded that biochar can be used as a soil amendment in fine textured soil to increase water holding capacity and to improve the drainage and hydraulic conductivity. The results showed that the application of biochar in a sandy clay loam soil could be used as an effective modifier to improve the physical properties of the soil and increase the FC, PWP and PAWC. Increasing the time and amount of biochar in soil resulted in significant changes in physical properties and soil moisture behavior. Unconventional application in sandy clay loam soils, especially in arid and semi-arid regions, due to lack of water resources in these areas, will be a good solution.

    Keywords: biochar, saturated hydraulic conductivity, field capacity, permanent wilting point, plant available water