شبیهسازی تاثیر زهکشی در پایین انداختن سطح ایستابی دشت فرخ آباد، دهلران | ||
| پژوهشهای دانش زمین | ||
| مقاله 13، دوره 11، شماره 2 - شماره پیاپی 42، 1399، صفحه 209-224 اصل مقاله (1.56 M) | ||
| نوع مقاله: مقاله پژوهشی | ||
| شناسه دیجیتال (DOI): 10.52547/esrj.11.2.209 | ||
| نویسندگان | ||
| حمیدرضا ناصری* 1؛ مرضیه سعیدی1؛ فرشاد علیجانی1؛ صادق علیمرادی2 | ||
| 1گروه زمینشناسی معدنی و آب، دانشکده علوم زمین، دانشگاه شهید بهشتی، تهران، ایران | ||
| 2شرکت آب منطقه ای ایلام، ایران | ||
| چکیده | ||
| روستای فرخآباد در حدود پنج کیلومتری جنوب غرب شهر دهلران واقع شده است. عمق کم سطح آب زیرزمینی در گسترهی این روستا باعث بروز مشکلاتی برای اهالی روستا شده و زندگی روزمره آنها را مختل کرده است. در این پژوهش استفاده از سیستم زهکشی برای پایین انداختن سطح آب زیرزمینی دشت فرخآباد مورد ارزیابی قرار گرفته است. در این مدل، ابتدا اطلاعات میزان بارندگی و تبخیر در گستره دشت، میزان تغذیه و تخلیه آبخوان از طریق کانالهای آبیاری، مسیر رودخانه میمه و همچنین میزان برداشت آب از چاهها و تغذیه آبخوان از فاضلاب برگشتی به نرم افزارVisual MODFLOW وارد شد. سپس رفتار هیدرولیکی آبخوان دشت با استفاده از نرمافزار مدلسازی شد. پس از واسنجی و صحت سنجی مدل، تاثیر اجرای سیستمهای مختلف زهکشی بر تراز سطح آب زیرزمینی دشت در قالب سه سناریوی شرایط هیدرولوژیک مرطوب، عادی و خشک شبیهسازی شد. براساس سناریوی اول افت سطح ایستابی در دوره مرطوب و عادی چهار تا پنج متر و در دوره خشک دو تا سه متر خواهد بود. نتایج حاصله نشان دهنده برتری روش زهکشی زیرزمینی(سناریوی اول) نسبت به احداث چاههای پمپاژ (سناریوی دوم) در پایین انداختن سطح ایستابی گستره مورد مطالعه میباشد. | ||
| کلیدواژهها | ||
| آب زیرزمینی- دشت فرخ آباد- زهکشی زیرزمینی- شبیه سازی؛ Visual MODFLOW | ||
| عنوان مقاله [English] | ||
| Simulation of drainage impact on lowering the water level of Farrokhabad plain, Dehloran | ||
| نویسندگان [English] | ||
| Hamid Reza Nassery1؛ Marzieh Saedy1؛ Farshad Alijani1؛ Sadegh Alimoradi2 | ||
| 1Department of Geology, Faculty of Earth Sciences, Shahid Beheshti University, Tehran, Iran | ||
| 2Regional Water Company of Illam, Iran | ||
| چکیده [English] | ||
| Introduction In countries such as Iran that are facing a shortage of water resources, paying attention to all water resources is of the utmost importance. Until recently, drainage management had received less attention and more drainage research focused on design issues. Following the 1992 World Summits, the International Committee on Irrigation and Drainage focused its attention on drainage management and emphasized the conservation and use of fresh-water resources in the context of comprehensive water management. Many studies have been conducted about the effects of high water levels in different aquifers. The study of the role and seasonal contribution of the drain in the hydrology of the region (King et al., 2014.) is among these studies. Nowadays, the underground drain is used to lower the water level. Among the studies in this regard, the effect of drainage system on lowering of groundwater level of Shiraz plain using groundwater model by Karimipour et al can be mentioned. (2012). Materials and Methods Farrokhabad plain in Dehloran is classified as folded Zagros based on the division of Iranian building units (Nabavi, 1977). Shallow water levels in the village of Farrokhabad (five kilometers southwest of Dehloran) have caused problems for the inhabitants of the village, demanding the village to move to other areas. In this study, the use of drainage system for lowering groundwater level of Farrokhabad plain is evaluated. In this regard, the hydraulic behavior of the aquifer of Farrokhabad plain was modeled using Visual MODFLOW code. After calibration and validation, the model of impact of drainage system on groundwater status of Dehloran plain was simulated under three different scenarios. Scenario One: Lowering the plain water level by underground drainage in dry, wet and normal hydrological conditions for a five-year period. Scenario 2: Lowering the plain water level by using pumping wells in dry, wet and normal hydrological conditions for a five-year period. Scenario 3: Water table drop in different hydrological periods without drainage. Results and Discussion The drainage system used in the first scenario includes a combination of the main collection drains with the gradient at the point of the Meymah River, where drainage discharges. Due to the curves of the water table level in the drainage range, the water level drop over five years in dry climatic conditions is about two to four meters, in wet hydrological conditions four to five meters, and in normal hydrological conditions. There are four to five meters of drainage area available. Then, a series of pumping wells were used to lower the water level, considering the potential curves in the range of pumping wells in arid climatic conditions, with a water level of about three to five meters during the normal five years. In five-year period with wet hydrological conditions, three to five and a half meters drop and in dry hydrological conditions a drop of three to five meters in the range of pumping wells were observed. Conclusion The results of the potential curves show better performance of wells than in the drain. However considering that the wells should be made to remove the water collected in them as well as transporting the water to other places, it requires more expenditures to drop the water level in this area. But with the proper design of the underground drain network, water can be transferred with gravity force to the Meymah river, and only the initial expenditure of the drainage is required. Though, with the proper design of the underground drainages, and the use of a layer of sand and coarse aggregate particles over the main branches of the drain can be used for several years. So with regard to the mentioned cases, it is more suitable to study the design of underground drainage wells. To lower the groundwater level to the desired depth, sub-drainage networks should be implemented in the direction of the land slope. | ||
| کلیدواژهها [English] | ||
| Groundwater, Farokh abad plain, Underground drainage, Simulation, Visual MODFLOW | ||
| مراجع | ||
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