تعیین مناسب ترین روش برآورد بار معلق در رود سیستان

نوع مقاله: مقاله پژوهشی

نویسندگان

1 دانشجوی کارشناسی ارشد، دانشکده ی آب و خاک، دانشگاه زابل

2 دانشیار، دانشکده ی آب و خاک، دانشگاه زابل

3 مربی، دانشکده ی آب و خاک، دانشگاه زابل

چکیده

رسوب‌گذاری در مسیر رود‌ها از بزرگ‌ترین مشکلات منابع آب سطحی به‌شمار آمده و باعث واردشدن زیان‌هایی به بناها و مزرعه‌ها و تغییر مسیر رودها می‌شود. روش‌های مختلفی برای تخمین بار رسوبی به‌کار برده‌می‌شوند اما به نحوه‌ی استفاده و دقت آن‌ها کم‌تر توجه شده است. در این پژوهش رود رسوب‌گذار سیستان در انتهای حوزه‌ی آب‌خیز رود هیرمند با شیبی ملایم و طول تقریبی 70 کیلومتر انتخاب شد. از آمار داده‌های متناظر آب‌دهی جریان و آب‌دهی بار‌معلق رود سیستان در طول دوره‌ی آماری سال‌های 1349 تا 1394 استفاده شد. برای افزایش دقت کار، داده‌ها به‌صورت ماهانه و فصلی طبقه‌بندی شدند. برآورد بارمعلق رود با 6 روش آماری یک‌خطی، دوخطی، حد وسط دسته‌ها، فائو، ضریب پارامتری (سی‌اف) و غیرخطی انجام گردید. با توجه به این‌که تعیین نقطه‌ی شکست در روش دوخطی اهمیت ویژه‌یی دارد از روش بهینه‌سازی به‌کمک الگوریتم ژنتیک برای تعیین آن استفاده شد. برای انتخاب روش مناسب براورد بارمعلق دو معیار ارزیابی میانگین خطای نسبی و جذر میانگین مربعات خطا به‌کار رفت. نتایج نشان دادند که روش دوخطی پیشنهادی در همه‌ی روش‌های بی‌تفکیک، تفکیک فصلی و ماهانه به‌ترتیب با میانگین خطای نسبی 154/46، 142/70 و 116/15 بهترین نتیجه را می ­دهد و تفکیک داده‌ها به‌صورت ماهانه باعث افزایش دقت و کاهش جذر میانگین مربعات خطا در رود سیستان می‌شود.

کلیدواژه‌ها


عنوان مقاله [English]

Determination of the Most Appropriate Statistical Method for the Suspended Load Estimation in the Sistan River

نویسندگان [English]

  • Naser Rahimi 1
  • Farzad Hassanpour 2
  • Salman Sharifazari 3
1 M.Sc. Student, Department of Water Eng., University of Zabol
2 Associate Professor, Department of Water Eng., University of Zabol
3 Lecturer, Department of Water Eng., University of Zabol
چکیده [English]

Sedimentation on the rivers beds causes many difficulties not only for an orderly and sustainable flow of water, but also by altering the rivers' hydraulics, which in certain cases drastically changes the flow direction by opening new channels that inundate farm fields, municipalities and infrastructures. As various models developed for the suspended load (SL) estimation are often site specific, therefore, it is prudent to test and calibrate them for the intended river. As the Hirmand River is the lifeblood of Sistan, therefore, the 70 km terminal reach, the Sistan River, was selected for this project. The monthly and seasonally discharge of the river and its SL contents for the period 1970–2015 were analyzed statistically using six models, namely: linear, double-linear, mean value, FAO, parametric factor and non-linear. As the determination of the break point is very important in the application of the double linear method, the genetic optimization algorithm was used in this process.Two criteria for choosing the correct method for estimation of the SL were used: relative mean error and root mean square error. It is concluded that the double linear method proposed in this research gives the best result in all forms without any delineation, seasonal and monthly classification with the relative mean error of 154.46, 142.7 and 116.15, respectively. Monthly classification of data increased accuracy and reduced the root mean square error in the Sistan River.

کلیدواژه‌ها [English]

  • Genetic algoritm
  • Sediment
  • Sistan river
  • suspended load
  • two linear method

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