مدلسازی اثرات کاهش برداشت چاههای مجاز، تجمیع و انسداد چاههای غیرمجاز بر وضعیت آب زیرزمینی دشت شبستر
First Statement of Responsibility
/خالدی علمداری
.PUBLICATION, DISTRIBUTION, ETC
Name of Publisher, Distributor, etc.
: کشاورزی
Date of Publication, Distribution, etc.
، ۱۳۹۶
Name of Manufacturer
، افشاری
NOTES PERTAINING TO PUBLICATION, DISTRIBUTION, ETC.
Text of Note
چاپی
CONTENTS NOTE
Text of Note
Groundwater is one of the most important agricultural and drinking water resource in arid and semi-arid countries, such as Iran. In recent decades, the abundant groundwater abstraction has eliminated the above-mentioned system from a state of equilibrium and caused a lot of negative consequences such as subsidence, cratering, water shortening, and reduction of groundwater quality. Therefore, it is necessary to take some operation to reduce the effects of these tensions on the environment. One of the effective tools in take decision and providing management solutions for groundwater is the modeling of aquifers. In this study, in order to modeling the Shabestar plain's aquifer and to apply management scenarios in the field of authorized and unauthorized agricultural wells, using the MODFLOW model in the GMS interface and after reviewing the general aquifer conditions, to apply the scenario, modeling and calibration has been done with at least as possible error. In a steady condition, it was calibrated in September of 2010 and in unsteady condition it is done for 24 months. Verification of the model was also carried out September of 2012 to August of 2013. After calibration and verification, the model was prepared for management scenarios, and the scenarios for reducing pumping rate, blocking of unauthorized wells and collecting unauthorized wells were applied in 12 different situations. The result shows in the scenario, the reduction in pumping rates by 40. from authorized wells could equilibrium the level of groundwater. The outputs of the model represent the desired effect of unauthorized wells blockage on the downward trend of groundwater level. The blockage of unauthorized wells and the provision of alternative wells -called collecting wells- have been import as scenarios to the model, and the results shows that have a positive impact on the application of this scenario, although between the rests of the scenarios, this have minor effect on groundwater level. As a general result, it can be concluded that reducing the pumping rates is the most effective, least costly and suitable scenario, because this can be executed by changing the pattern of cropping and installing smart counters. But in the case of blockage of unauthorized wells, it should be borne in mind that due to the dependence of the owners of these wells, their obstruction due to the dissatisfaction of the beneficiary communities will not be so successful and will have many physical and spiritual losses unless be is done with the accumulation and allocation of the right of the adjacent and permissible wells. Comparing the effect of blocking unauthorized wells and reduction in withdrawal on the groundwater level implied that to reduce the pumping rate about 20. is so close to the result from the blocking of unauthorized wells; on the other hand reduction in pumping rate about 10
DISSERTATION (THESIS) NOTE
Dissertation or thesis details and type of degree
کارشناسی ارشد
Discipline of degree
مهندسی آب
Date of degree
۱۳۹۶/۰۶/۱۵
Body granting the degree
تبریز
SUMMARY OR ABSTRACT
Text of Note
یکی از مهمصترین منابع آب موجود از لحاظ کشاورزی و شرب در کشورصهای خشک و نیمه خشک مانند ایران منابع آبصهای زیرزمینی میصباشد .در دههصهای اخیر برداشتصهای فراوان آبصهای زیرزمینی، سیستم منابع فوق را از حالت تعادل خارج نموده و تبعاتی منفی زیادی بمانند نشست زمین، ایجاد فروچاله، کاهش کمیت و کیفیت آنها را به دنبال داشته است .بنابراین ضروری است تدابیری برای کاهش اثرات این تنشصها بر محیط زیست اندیشیده شود .یکی از ابزارصهای مؤثر در تصمیمصگیری و ارائه راهکارصهای مدیریتی در رابطه با آبصهای زیرزمینی مدلصسازی آبخوانصها میصباشد .در این پژوهش به منظور مدلصسازی آبخوان دشت شبستر و اعمال سناریوصهای مدیریتی در برداشت آب از چاهصهای مجاز و غیر مجاز کشاورزی، با استفاده از مدل MODFLOW در محیط GMS پس از بررسی شرایط عمومی آبخوان، مدلصسازی انجام و با دقت مناسب برای اعمال سناریو، مورد واسنجی قرار گرفت .این واسنجی در دو حالت ماندگار در مهرصماه سال آبی۱۳۸۹ - ۹۰و در شرایط غیر ماندگار به مدت ۲۴ ماه مورد واسنجی قرار گرفت .صحتصسنجی مدل نیز در سال آبی۱۳۹۱ - ۹۲انجام پذیرفت .پس از پایان واسنجی و صحتصسنجی، مدل برای اعمال سناریوصهای مدیریتی آماده شد و سناریوصهای کاهش برداشت از چاهصهای مجاز، انسداد چاهصهای غیر مجاز و تجمیع چاهصهای غیر مجاز در ۱۲ حالت مختلف اعمال گردید .نتایج حاصل بهصاین ترتیب بود که در سناریو کاهش نرخ برداشت از چاهصهای مجاز کشاورزی با کاهش ۴۰ درصدی در میزان برداشت این چاهصها میصتوان سطح تراز آب زیرزمینی را تثبیت نمود و از روند نزولی آن جلوگیری به عمل آورد .خروجیصهای مدل بیانگر تأثیر مطلوب انسداد چاهصهای غیرمجاز بر روی روند نزولی تراز آب زیرزمینی میصباشد .انسداد چاهصهای غیرمجاز و ارائه چاه جایگزین برای آنصها که اصطلاحا تجمیع چاه نامیده میصشود به مدل معرفی شد و نتایج حاصل از آن تأثیر مثبت اعمال این سناریو را، هرچند کمتر از بقیه سناریوصها بر روی کاهش روند نزولی تراز آب زیرزمینی نشان داد .بصورت یک نتیجه کلی میصتوان گفت که کاهش میزان برداشت از چاهصهای مجاز مؤثرترین، کمصهزینهصترین و معقولصترین سناریو میصباشد، چراکه این امر به کمک تغییر در الگوی کشت و نصب کنتورصهای هوشمند میسر میصباشد .اما در خصوص انسداد چاهصهای غیرمجاز باید در نظر داشت که به لحاظ وابستگی مالکان این چاهصها، انسداد آنها به دلیل عدم رضایت جوامع ذینفع آنچنان موفق نخواهد بود و هزینهصهای مادی و معنوی بسیاری را در پی خواهد داشت .مگر اینکه بهمراه تجمیع و تخصیص حق آبه از چاهصهای مجاور و مجاز، اجرا شده باشد .با مقایسه ای که بین اثربخشی انسداد چاهصهای غیرمجاز و کاهش در برداشت بر روی تراز آب زیرزمینی صورت گرفت میصتوان دریافت که نتایج کاهش ۲۰ درصد در میزان برداشت از چاهصهای مجاز کشاورزی بسیار نزدیک به نتایج انسداد چاهصهای غیرمجاز کشاورزی میصباشد و از طرف دیگر با کاهش ۱۰ درصد در میزان برداشت میصتوان به نتایج نزدیک و مطلوبصتری نسبت به تجمیع چاهصهای غیرمجاز دست یافت .
Text of Note
Groundwater is one of the most important agricultural and drinking water resource in arid and semi-arid countries, such as Iran. In recent decades, the abundant groundwater abstraction has eliminated the above-mentioned system from a state of equilibrium and caused a lot of negative consequences such as subsidence, cratering, water shortening, and reduction of groundwater quality. Therefore, it is necessary to take some operation to reduce the effects of these tensions on the environment. One of the effective tools in take decision and providing management solutions for groundwater is the modeling of aquifers. In this study, in order to modeling the Shabestar plain's aquifer and to apply management scenarios in the field of authorized and unauthorized agricultural wells, using the MODFLOW model in the GMS interface and after reviewing the general aquifer conditions, to apply the scenario, modeling and calibration has been done with at least as possible error. In a steady condition, it was calibrated in September of 2010 and in unsteady condition it is done for 24 months. Verification of the model was also carried out September of 2012 to August of 2013. After calibration and verification, the model was prepared for management scenarios, and the scenarios for reducing pumping rate, blocking of unauthorized wells and collecting unauthorized wells were applied in 12 different situations. The result shows in the scenario, the reduction in pumping rates by 40 from authorized wells could equilibrium the level of groundwater. The outputs of the model represent the desired effect of unauthorized wells blockage on the downward trend of groundwater level. The blockage of unauthorized wells and the provision of alternative wells -called collecting wells- have been import as scenarios to the model, and the results shows that have a positive impact on the application of this scenario, although between the rests of the scenarios, this have minor effect on groundwater level. As a general result, it can be concluded that reducing the pumping rates is the most effective, least costly and suitable scenario, because this can be executed by changing the pattern of cropping and installing smart counters. But in the case of blockage of unauthorized wells, it should be borne in mind that due to the dependence of the owners of these wells, their obstruction due to the dissatisfaction of the beneficiary communities will not be so successful and will have many physical and spiritual losses unless be is done with the accumulation and allocation of the right of the adjacent and permissible wells. Comparing the effect of blocking unauthorized wells and reduction in withdrawal on the groundwater level implied that to reduce the pumping rate about 20 is so close to the result from the blocking of unauthorized wells; on the other hand reduction in pumping rate about 10 is approximately equal to integration of wells