سنجش پتانسیل سیل خیزی زیر حوضه ها بر اساس پارامترهای مورفومتری و آزمون همبستگی (مورد: حوضه آبریز زاب تا میرآباد)

اولویت بندی زیر حوضه‌ها از نظر پتانسیل سیل خیزی تاثیر مهمی در مدیریت حوضه آبریز دارد. هدف از اولویت بندی سیل خیزی در زیر حوضه‌ها ارائه الگویی برای کنترل و کاهش خطرات سیل و ارزیابی نقش هر یک از زیر حوضه‌ها در دبی اوج هیدروگراف سیلاب خروجی از حوضه می‌باشد. در این پژوهش پتانسیل سیل خیزی زیر حوضه‌های رودخانه زاب بر اساس پارامترهای 12 گانه مورفومتری ، اولویت بندی زیر حوضه‌های آبریز زاب بر اساس روش ترکیبی آنالیز مورفومتریک و همبستگی آماری انجام شد. در ابتدا مقادیر 12 پارامتر مورفومتری و شاخص (cv) محاسبه شده است. سپس ارتباط بین پارامترهای مورفومتریک و تعیین وزن تاثیر هر یک از آنها با استفاده از تای کندال و آنالیز مجموع وزنی (wsa) تحلیل شد. در نهایت شاخص اولویت بندی زیر حوضه‌های آبریز (swpi) بر اساس روش ترکیب خطی وزنی (wls) برای هر یک از زیر حوضه ها محاسبه شد. به منظور اعتبار سنجی نتایج از داده های موقعیت سیل های مخرب گذشته در حوضه آبریز زاب استفاده گردید. نتایج نشان داد که در روش پتانسیل سیل خیزی که بر اساس 12 پارامتر مورفومتری محاسبه شده زیر حوضه‌های شین آباد و صوفیان دارای پتانسیل زیاد سیل خیزی، زیر حوضه زاب کوچک دارای پتانسیل متوسط و زیر حوضه‌های کوپر و لاوین چای دارای پتانسیل کمی برای سیل خیزی می‌باشند. در واقع 83/33% مساحت حوضه زاب دارای پتانسیل خطر زیاد، 28/14% دارای پتانسیل خطر متوسط و 88/51% دارای پتانسیل خطر کم می‌باشد. نتایج حاصل از پارامترهای مورفومتری و همبستگی آماری نشان داد به ترتیب زیر حوضه‌های شین آباد و صوفیان با مقادیر 67/24 و 46/23 اولویتدارترین زیر حوضه‌ها شناسایی شدند. مقایسه نتایج دو روش با شرایط مورفومتری و ژئومورفولوژی زیر حوضه‌ها نشان می‌دهد نتایجی که با تکیه بر 12 پارامتر مورفومتری حاصل شده است تطبیق بیشتری با شرایط ژئومورفیک حوضه دارد

Evaluation of flood potential under basins based on morphometric parameters and correlation test(Case: Zab catchment to Mirabad)

IntroductionThe concept of morphometry involves the measurement and numerical analysis of land surface, shape, dimensions and form of land. In relation to flooding, watershed morphometry includes quantitative indicators describing watershed physical characteristics that control the pattern and quantitative characteristics of floods such as amount, time of occurrence, delay time, and flow hydrograph. Unusual development of cities due to population growth and consequent land use change has caused disruption of hydrological balance and increased flooding of basins. The purpose of this study was to prioritize the subcatchments of Zab River based on a novel combination of morphometric analysis and statistical correlation and zoning of flood potential under subcatchments.Data and Methodto disregard for human and social subbasins, which has a great impact on the hydrological processes of the catchment. Based on the validation results, the Shinabad and Sufian basins have the highest priority, and the new method of morphometric analysis and statistical correlation have considered them the highest priority for managers’ attention.The elongation ratio helps to understand the hydrological characteristics of the drainage basin and ranges from 1 for circular basins to 0 for extended basins and its high values ​​indicate the shape of the basin circle, high peak discharge and high flood potential. Is. The values ​​of tensile strength in all sub basins are more than 0.5 and indicate high potential for flooding. Straller (1964) considers the circle ratio a quantitative measure for visualizing the shape of the basin. High values ​​of this parameter indicate circular shape, high to medium ruggedness and low permeability in the basin, which causes peak discharge in less time. The ratio of the circular ratios under the Lavin Tea Basins is 0.17, Copar 0.19, and Zab Small 0.27, indicating relatively low flooding potential in this parameter. The amount of this parameter is 0.35 under Shinabad basin and 0.31 under Sufian basin which indicates their higher flood potential in this parameter (Table 7). The branching ratio is an important parameter affecting peak runoff hydrograph discharge with high values ​​indicating high instantaneous discharge and flood event. The mountainous and steep areas have a split ratio of 3 to 4. Branching ratio values ​​indicate low flooding potential except for Shinabad basin which shows this ratio of 6.19 and this ratio indicates high flood potential Results and DiscussionSince hydrological units are based on morphometric parameters to prioritize flood mapping, firstly, using channel networks and elevation curves, topographic maps of 1: 50000 and digital elevation data are analyzed. The boundaries of the hydrological units became. Then, because the catchment morphological parameters have different effects on soil erosion processes and runoff formation, prioritization of the subbasins was done in a new way based on the difference of morphological parameters and statistical correlation analysis between them. Morphometric parameters were calculated for all subbasins in GIS software. Then, statistical correlation of morphometric parameters was performed based on the tKendall method using SPSS software. Based on the correlation matrix we can analyze the relationship between the parameters and define the relative weight for each parameter without All twelve variables including circular elongation ratio, branching ratio, flow frequency, drainage density, drainage texture, compaction index, shape factor, mean slope, roughness ratio, roughness, and roughness number for all subbasins are calculated in Table 2. The Kendall correlation coefficient was used to investigate the relationship between Validation results showed that the new method of morphometric analysis and statistical correlation did not perform well in prioritizing all subbasins, but this method was accurate in identifying the most priority subbasins (most acute conditions). The reason for this may be due to the lower performance of morphometric analysis and the characterization of waterways in lowslope catchments. Also, the precise reason for not estimating the priority of some subbasins is due.ConclusionThe selected twelve parameters are directly related to runoff and flood potential. Therefore, high values ​​of parameters have a direct relationship with runoff and flood potential due to their greater impact on the selected twelve parameters. Indicator (Cv) values ​​for each subbasin are obtained from averaging of 12 indices and accordingly subbasins of Shinabad and Sufis with high flood potential, subbasin with small potential and subbasin zab basin. Copar and Lavin Tea have physiographic and morphometric characteristics of the subcatchments have a great influence on flooding and hydrological behavior, it is possible to study the status and potential of flooding below the catchments. In this research, in order to potential of flooding, firstly, Zab subbasins were prioritized based on the new method of morphometric analysis and statistical correlation. Based on this method, the results showed that the Shin abad and Sufi basins are the top priority for the implementation of management measures to ensure.