نشریه علمی - پژوهشی مرتع و آبخیزداری

نوع مقاله : مقاله پژوهشی

نویسندگان

1 دانشیار دانشکده منابع طبیعی، دانشگاه تهران، کرج، ایران

2 کارشناس ارشد، اداره کل منابع طبیعی و آبخیزداری استان کردستان، ایران

چکیده

داشتن اطلاع از مقدار کمی بار رسوبی حمل شده توسط رودخانه‌ها از اساسی‌ترین اطلاعات برای مقابله با فرسایش خاک و طراحی سدهای ‌می‌باشد. در ایران غالبا برآورد بار رسوب معلق بر پایه روش‌های منحنی سنجه می‌باشد. از آن‌جا که داده‌های برداشت دبی رسوب به طور تصادفی و ناپیوسته می‌باشد لذا، در عمل درونیابی و برونیابی آن‌ها با خطای زیادی همراه می‌باشد. این بررسی به منظور ارزیابی در تعداد داده‌های موجود برای برآورد بار رسوبی روزانه با مدل‌های رگرسیونی Loadest است. بنابراین از داده‌های دبی روزانه رسوب ایستگاه قزاقلی در حوزه آبخیز جنگلی گرگانرود استفاده شد. با توجه به نتایج ارزیابی (دیاگرام تیلور) مدل شماره 2 دارای بهترین دقت بوده و در صورت نبود تا 50 درصد از داده‌های روزانه رسوب، ضریب همبستگی بیش از 5/0را در برآورد رسوب سالانه و آن هم فقط برای سال اول از خود نشان داد و در مابقی سال‌های مورد تحقیق ضریب همبستگی غیر قابل قبول است. بنابراین استفاده از روش‌های منحنی سنجه رسوب با داده‌های موجود در سطح ایستگاه‌های ایران، در صورتیکه تعداد داده موجود برای ساخت منحنی سنجه کمتر از 185 عدد باشد با دقت بسیار کمی همراه خواهد بود. همچنین هرچقدر مقدار داده موجود متعلق به دوره های حمل رسوب کم (فصل پاییز و سال خشک) بیشتر باشد کارایی روش Loadest کمتر خواهد بود. با توجه به اینکه در برخی مطالعات برای برآورد و واسنجی مدل SWAT از ایجاد ارتباط بین مدل Loadestبا مدل SWATاستفاده می‌شود،

کلیدواژه‌ها

عنوان مقاله [English]

Ability of Loadest Regression Methods to Estimate Annual Suspended Sediment

نویسندگان [English]

  • Aliakbar Nazari Samani 1
  • Aryan Salvati 2

1 Faculty of Natural Resources, University of Tehran, Karaj, Iran

2 Master of Science in Natural Resources

چکیده [English]

Having knowledge on the quantitative amount of watershed sediment yield is one of the most basic information to deal with soil erosion and conservation as well as design of dams. In Iran, the estimation of suspended sediment load is often based on measurement curve methods. Since sediment discharge data are random and discontinuous, in practice, their internalization and extrapolation is associated with many errors. This review is to evaluate the number of data available to estimate daily sediment load with Loadest regression models. Therefore, daily discharge data of Ghazaghli station in Gorganrood forest watershed were used. So that different percentages of available data were accidentally deleted and the amount of sediment load was estimated by 11 methods. According to the evaluation results (Taylor diagram), model number 2 has the best accuracy and in the absence of up to 50% of the daily sediment data, the correlation coefficient of more than 0/5 in the annual sediment estimation and only for the first year And in the rest of the years under study the correlation coefficient is unacceptable. Therefore, the use of sediment measurement curve methods with the data available at the level of Iranian stations, if the number of data available to construct the measurement curve is less than 185 will be associated with very little accuracy. Also, the higher the amount of available data belonging to the periods of low sediment transport (autumn and dry years), the lower the efficiency of the Loadest method will be.

کلیدواژه‌ها [English]

  • Taylor diagram
  • Gorganrood
  • correlation coefficient
  • Suspended sediment
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