مقایسه روش‌های شیب و انحنا برای برآورد حداقل جریان زیست‌محیطی رودخانه به روش هیدرولیکی

نویسندگان

چکیده

برآورد و تخصیص جریان زیست‌محیطی،‏ مؤثرترین رویکرد برای جلوگیری از اثرات منفی تنظیم جریان‌های سطحی بر اکوسیستم‌ها است. روش محیط خیس شده از روش‌های مفید در این زمینه است. آنچه در این روش مهم است،‏ تعیین نقطه بحرانی در منحنی دبی- محیط خیس شده است که همچنان ابهاماتی دارد. در این مقاله حداقل جریان زیست‌محیطی رودخانه خیرآباد با متوسط جریان سالانه (AAF)‎ 34 مترمکعب بر ثانیه با روش محیط خیس شده براساس دو روش شیب و انحنا برای تعیین نقطه بحرانی محاسبه شده است. نتایج نشان می‌دهد روش شیب همواره مقدار بیشتری نسبت به روش انحنا به دست می‌دهند. نتایج روش‌های شیب و انحنا به طور متوسط به‌ترتیب جریانی برابر با 2‎/5 و 0‎/2 متر‌مکعب بر ثانیه را به دست دادند. با مقایسه نتایج حاصل از دو روش با محدوده قابل قبول جدول تنانت (AAF 10-30%) مشخص شد که نتایج روش شیب (AAF 3‎/15%) در این محدوده قرار می‌گیرد ولی نتایج روش انحنا (AAF 6%) خارج از محدوده قابل قبول است. با توجه به این نتایج روش انحنا نمی‌تواند انتخابی مناسب برای تعیین نقطه بحرانی در منحنی باشد و در این زمینه روش شیب مقادیر قابل قبولی در پی دارد.

کلیدواژه‌ها


عنوان مقاله [English]

Comparison of the slope and curvature techniques for estimation of the minimum environmental flow of river using hydraulically method

نویسندگان [English]

  • Seyed Jamal Poursalehan
  • Mohammad Sedghi-Asl
  • Mansour Parvizi
چکیده [English]

Estimation and allocation of environmental flow are the most effective approach to avoid the negative effects of the regulation of surface flows on the ecosystems. One of the useful approaches in this field is the wetted perimeter method. Determination of critical point in the P-Q curve is an important issue in this method, which is still associated with ambiguity. In this paper, the minimum environmental flow of Kheyr-Abad River, with the average annual flow (AAF) of 34 m3/s, is calculated using the wetted perimeter method based on the slope and curvature techniques for determining the critical point. The results indicated that the slope technique always gives higher values than curvature technique. The calculated values for flow using the slope and curvature techniques were equal to 5.2 and 2.0 m3/s, respectively. By comparing the results of both techniques with the acceptable range of Tennant’s table (10-30 percent's of AAF), it is specified that the results of slope method (15.3% of AAF) are located in this range, while the results of the curvature technique (6.0% of AAF) don’t lie in the acceptable range. The results indicated that the curvature technique cannot be a suitable choice for determining the critical point in the curve and the slope technique presented acceptable results.Estimation and allocation of environmental flow are the most effective approach to avoid the negative effects of the regulation of surface flows on the ecosystems. One of the useful approaches in this field is the wetted perimeter method. Determination of critical point in the P-Q curve is an important issue in this method, which is still associated with ambiguity. In this paper, the minimum environmental flow of Kheyr-Abad River, with the average annual flow (AAF) of 34 m3/s, is calculated using the wetted perimeter method based on the slope and curvature techniques for determining the critical point. The results indicated that the slope technique always gives higher values than curvature technique. The calculated values for flow using the slope and curvature techniques were equal to 5.2 and 2.0 m3/s, respectively. By comparing the results of both techniques with the acceptable range of Tennant’s table (10-30 percent's of AAF), it is specified that the results of slope method (15.3% of AAF) are located in this range, while the results of the curvature technique (6.0% of AAF) don’t lie in the acceptable range. The results indicated that the curvature technique cannot be a suitable choice for determining the critical point in the curve and the slope technique presented acceptable results.Estimation and allocation of environmental flow are the most effective approach to avoid the negative effects of the regulation of surface flows on the ecosystems. One of the useful approaches in this field is the wetted perimeter method. Determination of critical point in the P-Q curve is an important issue in this method, which is still associated with ambiguity. In this paper, the minimum environmental flow of Kheyr-Abad River, with the average annual flow (AAF) of 34 m3/s, is calculated using the wetted perimeter method based on the slope and curvature techniques for determining the critical point. The results indicated that the slope technique always gives higher values than curvature technique. The calculated values for flow using the slope and curvature techniques were equal to 5.2 and 2.0 m3/s, respectively. By comparing the results of both techniques with the acceptable range of Tennant’s table (10-30 percent's of AAF), it is specified that the results of slope method (15.3% of AAF) are located in this range, while the results of the curvature technique (6.0% of AAF) don’t lie in the acceptable range. The results indicated that the curvature technique cannot be a suitable choice for determining the critical point in the curve and the slope technique presented acceptable results.Estimation and allocation of environmental flow are the most effective approach to avoid the negative effects of the regulation of surface flows on the ecosystems. One of the useful approaches in this field is the wetted perimeter method. Determination of critical point in the P-Q curve is an important issue in this method, which is still associated with ambiguity. In this paper, the minimum environmental flow of Kheyr-Abad River, with the average annual flow (AAF) of 34 m3/s, is calculated using the wetted perimeter method based on the slope and curvature techniques for determining the critical point. The results indicated that the slope technique always gives higher values than curvature technique. The calculated values for flow using the slope and curvature techniques were equal to 5.2 and 2.0 m3/s, respectively. By comparing the results of both techniques with the acceptable range of Tennant’s table (10-30 percent's of AAF), it is specified that the results of slope method (15.3% of AAF) are located in this range, while the results of the curvature technique (6.0% of AAF) don’t lie in the acceptable range. The results indicated that the curvature technique cannot be a suitable choice for determining the critical point in the curve and the slope technique presented acceptable results.