گزارش فني: ارزيابي تأثير چكدم بر روي خصوصيات هيدروديناميكي سيل

Assessment of check dams effect on hydrodynamic features of flood

ﺳﯿﻞ ﺑﻪﻋﻨﻮان ﻣﻬﻤﺘﺮﯾﻦ و ﻓﺮاوانﺗﺮﯾﻦ ﻣﺨﺎﻃﺮات ﻣﺤﯿﻄﯽ اﺳﺖ ﮐﻪ ﻣﯽﺗﻮاﻧﺪ ﻣﻮﺟﺒﺎت ﺧﺴﺎرات ﺷﺪﯾﺪ ﺟﺎﻧﯽ و ﻣﺎﻟﯽ را ﻓﺮاﻫﻢ ﮐﻨﺪ. در ﺑﺴﯿﺎري از ﻣﻮارد ﺗﻐﯿﯿﺮ ﮐﺎرﺑﺮي اراﺿﯽ ﻣﻮﺟﺐ ﺑﺮوز ﺳﯿﻞ ﻣﯽﺷﻮد. در اﯾﻦ ﻣﻄﺎﻟﻌﻪ، در ﺣﻮﺿﻪ ﮔﻨﺒﺪﭼﺎي ﺑﺮاي ﺑﺮرﺳﯽ ﺗﺄﺛﯿﺮ ﭼﮑﺪمﻫﺎ )ﻋﻤﻠﯿﺎت ﻣﮑﺎﻧﯿﮑﯽ آﺑﺨﯿﺰداري( ﺑﺮ روي ﺳﯿﻞ، اﺑﺘﺪا ﺑﺎ اﺳﺘﻔﺎده از روش ﻓﺎزيﺳﺎزي و AHP و ﺗﺮﮐﯿﺐ ﭼﻬﺎر ﻧﻘﺸﻪ ﺷﯿﺐ، ارﺗﻔﺎع، ﮐﺎرﺑﺮي اراﺿﯽ و ﻧﻔﻮذﭘﺬﯾﺮي ﻧﻘﺸﻪ ﭘﺎﯾﻪ ﺗﻬﯿﻪ ﺷﺪ. در ﻗﺪم ﺑﻌﺪي ﺑﺎ ﺟﺎﻧﻤﺎﺋﯽ ﭼﮑﺪمﻫﺎ و ﺗﻔﮑﯿﮏ اﯾﻦ ﻋﻤﻠﯿﺎت ﺑﺮ اﺳﺎس ارﺗﻔﺎع و داﻣﻨﻪ ﺗﺄﺛﯿﺮ ﻫﺮ ﮐﺪام از اﯾﻦﻫﺎ ﺑﺎ اﺳﺘﻔﺎده از ﺧﻄﻮط ﺗﺮاز ارﺗﻔﺎﻋﯽ، ﻧﻘﺸﻪ ﻣﺮﺑﻮﻃﻪ ﺗﻬﯿﻪ ﺷﺪ. در ﻧﻬﺎﯾﺖ، ﺑﺎ ﺗﻠﻔﯿﻖ ﻧﻘﺸﻪ ﻣﺮﺑﻮط ﺑﻪ داﻣﻨﻪ ﺗﺄﺛﯿﺮ ﭼﮑﺪمﻫﺎ ﺑﺎ ﻧﻘﺸﻪ ﭘﺎﯾﻪ ﺑﻪ ﺑﺮرﺳﯽ ﭘﻬﻨﻪﺑﻨﺪي ﺳﯿﻞ در ﻣﻨﻄﻘﻪ ﻣﻮرد ﻣﻄﺎﻟﻌﻪ ﭘﺮداﺧﺘﻪ ﺷﺪ. ﻧﺘﺎﯾﺞ ﮔﺮﭼﻪ در ﮐﻞ، ﺗﺄﺛﯿﺮ ﻣﺜﺒﺖ ﻧﻪ درﺻﺪ و ﮐﻤﺘﺮ اﯾﻦ ﭼﮑﺪمﻫﺎ را ﺑﺮ روي ﮐﺎﻫﺶ ﺧﻄﺮات ﻧﺎﺷﯽ از ﺳﯿﻞ را در ﮐﺎﻫﺶ ﺳﯿﻞ ﻧﺸﺎن ﻣﯽدﻫﺪ وﻟﯽ اﯾﻦ ﻧﺘﺎﯾﺞ در ﮐﺎرﻫﺎي اﺟﺮاﺋﯽ در ﻣﻘﺎﯾﺴﻪ ﺑﺎ ﮐﺎرﻫﺎي ﭘﯿﺸﻨﻬﺎدي ﺑﺴﯿﺎر ﮐﻢ اﺳﺖ ﮐﻪ ﻋﻠﺖ اﯾﻦ اﻣﺮ را ﻣﯽ ﺗﻮان در ﻧﺎﻣﻨﺎﺳﺐ ﺑﻮدن ﭘﺮاﮐﻨﺪﮔﯽ و ﺗﻌﺪاد ﮐﻢ ﻋﻤﻠﯿﺎت اﺟﺮاﺋﯽ ﺟﺴﺖ و ﺟﻮ كرد.

Flooding is one of the most important environmental hazards that can cause severe damage to life and financial damage. In many cases land use changes cause flooding. In this study in Gonbad Chi warershed to assess the impact of proposed and the built watershed mechanical operations (check dams) on flood mapping, firstly the fuzzy logic and AHP were used to prepare base map based on combination of layers i.e. slope, land use, Permeability and flow accumulation. In next step by determining the location of check dams and separation of the operation according to dam height and determine the extent of the effect of the check dams using elevation contour lines, the mapping of impact of watershed management operations was prepared. In the end with composition of base mapping with impact of check dams, a new map that called flood mapping is created. Although the results have a positive impact 9% and less than it on reducing the risks of flood but these results in built check dams is very low than proposed check dams but in total the impact of built and proposed dams is low that it’s result is from low number and distribution of check dams.