اثر مقیاس کرت بر رواناب تحت بارندگی طبیعی (مطالعه موردی: سراوان رشت)

نوع مقاله: مقاله پژوهشی

نویسندگان

1 دانشگاه گیلان

2 عضو هیات علمی گروه علوم خاک داشگاه تهران

3 استادیار- گروه مهندسی آب - دانشگاه گیلان

چکیده

یکی از چالش‌هایی که در پیشرفت مطالعات علوم خاک و هیدرولوژی وجود دارد این است که نظریه‌ها برای مقیاس زمانی و مکانی خاصی به‌کار می‌روند. این تحقیق به منظور بررسی اثر اندازه کرت برتولید رواناب و کمی کردن اثرات مقیاس انجام شد. برای این هدف، شش کرت آزمایشی با طول 3 تا 60 متر و عرض 1 تا 6 متر در یک دامنه در منطقه سراوان رشت در استان گیلان احداث شد. میزان رواناب در 14 رخداد طبیعی باران از مهر سال 1394 تا اردیبهشت 1395 جمع‌آوری و سپس مورد تجزیه و تحلیل قرارگرفت. همچنین با نصب باران‌سنج، ارتفاع باران برای هر کرت اندازه‌گیری شد. نتایج نشان داد رواناب در واحد سطح با افزایش طول کرت به صورت غیر خطی کاهش می‌یابد. مقایسه میانگین بین کرت‌ها نشان داد که کرت‌های با طول بیش‌تر از 10 متر اختلاف معنی‌داری از نظر تولید رواناب با هم ندارند. با این حال کرت‌های زیر 10 متر با کرت‌های بزرگ‌تر اختلاف معنی‌داری از نظر تولید رواناب نشان دادند (P >0/05). براساس نتایج، کرت با طول 10 متر حداقل طول مناسب برای مقیاس‌بندی است. برای مقیاس‌بندی ضریب رواناب دامنه، از یک مدل دو پارامتری استفاده شد. پارامترهای مدل با استفاده از واسنجی مدل با استفاده از داده‌های نه رخداد تعیین شدند. ارزیابی مدل با پنج رخداد باقیمانده، بیان‌گر کارایی مناسب این مدل در کرت‌های کوچک‌تر از 30 متر بود.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Effect of plot scale on runoff under natural rainfall (Case study; Saravan region, Rasht)

نویسندگان [English]

  • Misagh Parhizgar 1
  • Hossein Asadi 2
  • Sayed Ali Moussavi 3
1 University of Guilan
2 University of Tehran
3 Lecturer, Department of Water Engineering, University of Guilan
چکیده [English]

One of the challenges to progress in hydrology and soil science researches is that the theories are only applied to certain time-space scales. This study was carried out to find out the effect of plot size on runoff generation and to quantify it’s scale effects on runoff generation. For this purpose, 6 experimental plots with the length of 3 to 60 m and the width of 1 to 6 m were established on a hillside in the Saravan region of Rasht, Guilan province, Iran. The outflow runoff data was collected from October to May 2015, and then the data were analyzed. Also, the height of rainfall was measured for each plot using rain gauges. Results of the study showed that as the length of plots increase, the amount of runoff per unit area decrease with a non-linear pattern. The Comparison between the mean values  of the plots confirmed that there are no significant differences among plots with lengths longer than 10 m in terms of runoff yield. However, there were significant differences among plots with a shorter or a longer size (P > 0/05). The research results verified the optimal length of 10 m for scaling proposes. A two-parameter model was used for scaling hillslope runoff ratio. Model  parameters were determined by model calibration using 9 rain events. The evaluation of the model showed its appropriate efficiency for plots shorter than 30 m long.              

کلیدواژه‌ها [English]

  • Erosion plots
  • Infiltration
  • Runoff coefficient
  • Scaling
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