بررسی نقش رودخانه‌‌ها در آینده احتمالی خلیج گرگان پس از جدایی از دریای کاسپی

نوع مقاله : مقاله پژوهشی

نویسنده

مربی، دانشکده شیلات و محیط زیست، دانشگاه علوم کشاورزی و منابع طبیعی گرگان، ایران

چکیده

در این تحقیق آینده احتمالی خلیج گرگان پس از جدایی از دریای کاسپی تحت پنج سناریو با استفاده از مدل مایک21 بررسی گردید. در سناریو اول خلیج متاثر از اقلیم حاکم بر آن بررسی و در سناریو دوم آینده خلیج متاثر از اقلیم حاکم و ورودی رودخانه‌‌ها بررسی شد. در سه سناریوی بعدی خلیج تحت‌‌تاثیر اقلیم و حداقل نیاز محیط‌‌زیستی رودخانه‌‌ها مطابق پیشنهادهای تنانت  (1976)بررسی شد. نتایج مدل‌‌ تحت سناریو اول نشان داد که 551 روز بعد جدایی خلیج از دریا، خلیج متاثر از شرایط اقلیمی به خشکی مبدل خواهد شد. نتایج مدل‌‌سازی تحت سناریو دوم نشان داد که خلیج بعد گذشت 1110 روز به یک تالاب درون‌‌خشکی با حداقل مساحت 51 کیلومترمربع مبدل می‌‌گردد. نتایج مدل‌‌سازی‌‌ها تحت سناریوهای سوم، چهارم و پنجم نشان داد که خلیج بعد گذشت 653، 665 و 1015 روز به یک تالاب درون‌‌خشکی به‌‌ترتیب با حداقل مساحت 7، 12 و 32 کیلومترمربع مبدل می‌‌گردد. مادامی‌‌که خلیج گرگان با دریای مادری در ارتباط باشد تعیین حق‌‌آبه زیستی از رودخانه‌‌های منتهی به آن هیچ کمکی به افزایش سطح آب و جلوگیری از خشکی‌‌زدگی نخواهد کرد، ولیکن پس از جدایی خلیج از دریای مادری تامین آب از طریق رودخانه‌‌ها در تشکیل تالاب درون‌‌خشکی تاثیر به سزایی خواهد گذاشت. وزش بادهای غالب شمالی و غربی بیشترین تاثیر را در افزایش مساحت خلیج در بخش شمال‌‌شرقی و تشکیل تالابچه‌‌های موقتی تحت سناریوهای مفروض به‌‌دلیل ایجاد برکشند توفان خواهند داشت. در صورت قطع ارتباط خلیج با دریا و عدم تامین حق‌‌آبه رودخانه‌‌ها، جانشینی بوم‌‌شناختی در خلیج گرگان از نوع مخرب خواهد بود. 

کلیدواژه‌ها


عنوان مقاله [English]

Investigating the Rivers Role in the Gorgan Bay Possible Future After Separation From the Caspian Sea

نویسنده [English]

  • Saeed Sharbaty
Lecturer Dept. of Fisheries Gorgan University Agricultural Sciences and Natural Resources, Iran
چکیده [English]

Investigating the Rivers Role in the Gorgan Bay Possible Future After Separation From the Caspian Sea
 
In this research, the probable future of the Gorgan Bay after separation from the Caspian Sea under five scenarios is examined using Mike 21 model. In the first scenario, the bay was studied under the influence of the prevailing climate on it. In the second scenario, the bay was studied under the influence of the climate and river inputs. In the next three scenarios, bay was assessed under the influence of climate and rivers environmental minimum requirements according to Tennant (1976) suggestions. The modeling results under the first scenario showed that, 551 days after the separation of the bay from the Sea, the bay would be dwarfed by the climate conditions. Modeling results under the second scenario showed that bay after 1110 days, it becomes a wetland with a minimum area of 51 km2. Modeling results under the third, fourth and fifth scenarios showed that the bay after 653, 665 and 1015 days into a wetland with a minimum area of 7, 12 and 32 km2 respectively. So long as the Gorgan Bay be connected to the mother sea determining the biological water right from rivers leading to it will not help to increasing the water level and prevent dryness of the bay. However, after separating the bay from the mother sea water supply through rivers will have a significant impact on the formation of wetland. The northern and western prevailing winds have a greatest impact on increasing of the bay area in the northeast part and temporary wetlands creating under presumed scenarios due to the formation of stormsurg. If the bay does not communicate with the sea and does not provide water right supplies of rivers, ecological successions in the Gorgan bay will be disclimax.

کلیدواژه‌ها [English]

  • Gorgan bay
  • River
  • Tennant
  • Simulation
  • MIKE 21
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