استخراج آبنمود(هيدروگراف) واحد ژيومورفولوژيكي بر اساس روش لوپز و مقايسه آن با آبنمودهاي مشاهداتي در حوضه حسين‌آباد

Extraction Geomorphological unit hydrograph based on the model Lopez and compare with observed hydrographs in the Hossein Abad basin

در اين مقاله مدل آب نمود يا هيدروگراف هاي واحد ژيومورفولوژي مخزن(GUHR) براي حوضه حسين‌آباد واقع در استان كردستان ارايه شده است. اين مدل بر پايه مفهوم مخازن خطي آبشاري جهت تخمين سيلاب حوضه هايي با داده هاي محدود به كار مي رود. در همين راستا، كاربرد مدل هيدروگراف واحد ژيومورفولوژي مخزن (GUHR) بر اساس مدل لوپز و مخازن خطي آبشاري و مقايسه نتايج آن با هيدروگراف هاي مشاهداتي در حوضه حسين‌آباد هدف اساسي اين پژوهش است. در مدل مذكور سطوح شبكه زهكشي حوضه به صورت مخازن خطي آبشاري در نظر گرفته مي شود. تعداد و اندازه اين مخازن بر مبناي زير حوضه ها در طول شبكه زهكشي حوضه لحاظ مي شود. نتايج بيانگر آن است در اين مدل هيدروگراف هاي واحد به تغيير پارامتر k حساس هستند زيرا با تغيير پارامتر k تغيير زيادي در ميزان دبي اوج، رسيدن به دبي اوج و شكل كلي هيدروگراف مشاهده مي شود. هم چنين از مقايسه هيدروگراف هاي سيلاب مدل به ازاي k متوسط بهينه و هيدروگراف هاي مشاهداتي رويدادها و نتايج صحت‌سنجي مدل مشخص مي شود كه مي توان k متوسط بهينه حاصل را به عنوانk متوسط حوضه در نظر گرفت. مدلGUHR با وجود داشتن يك پارامتر، به دليل به‌كارگيري خصوصيات ژيومورفولوژي حوضه، توانايي مناسبي در شبيه‌سازي بارش- رواناب دارد. بنابراين قابل كاربرد در ديگر حوضه هاي آبخيز با شرايط يكسان مي باشد.

Extended Abstract: Introduction Creating a point of unit hydrograph from drainage basin as a response to a rainfall event is a complex process depending on the characteristics of precipitation and watershed characteristics.In the past decade, many studies to understand of this process has been carried out in catchments including models developed in this regard the geomorphological unit hydrograph model is that by Rodriguez Aytorb and Valdez as a reaction to the arrival of a unit of excess rainfall catchment basin presented to the input of a single moment moments of excess rainfall are presented. Adib et al (98:2010) research model of Instantaneous Unit Hydrograph Geomorphoclimatologhy GCIUH a model based on Clark (GCIUH-Clark) and unit hydrograph model based on the Nash model klysan Basin have been evaluated. Therefore Instantaneous Unit Hydrograph (IUH) in the model Clark through software HEC-HMS and the model Nash through data - rainfall - runoff was determined by the results of the two models derived flood hydrograph accuracy and high performance are shown. The purpose of this study geomorphology unit hydrograph model repository (GUHR) based on a cascade of linear reservoirs and compare these with the watershed hydrograph observation is Hossein Abad is located in the province of Kurdistan. Materials and Methods At the beginning of the drainage basin on Map1/ 25000 limit for each sub-basin area extraction unit hydrograph model was determined by Lopez et al model. Next, classified according to the degree Lopez et al (2005:133) drainage basin Hossein Abad was classified grading drainage basin in Figure 3 is given. The comparison between the four event hydrograph observation hydrograph simulated by the model and the data limitations the time of the runoff and precipitation is used. Of these, three-event model and event model was employed for verification.in GUHR model surface drainage basin, a cascade of linear reservoirs is considered to be Based on the size and number of tanks during drainage basin basin is considered. According to Chow et al (1988) Reservoir storage volume S (T), storage coefficient K linearly with output, Q (T), is related to. Namely: S (T)= K.Q(T) Equations by applying the same degree drainage system of equations can be obtained. So for any reservoir with the specified input differential equation assuming a uniform distribution of rainfall in the basin and constant storage coefficient K is obtained for the entire reservoir. In the model GUHR, K using direct runoff hydrograph time between centers of gravity (DRH) and effective Hytograph ER (ERH) is obtained from the following equation (Lopez, 2005): K=?(A_T[t_(DRH-t_ERH ) ] /(?_(i=1)^n??jA_i ?)) Results and discussion Hydrographs of direct runoff by subtracting the base flow fixed any of the hydrograph observed determined through index ? for each event precipitation calculated from observations Hytographs, the fraction was Hytographs rainfall during construction resulting be. Then the parameter k for each event were calculated on the basis of K obtained are given yield determined by trial and error (testing) optimized K by minimizing the error between optimum unit from the model and the optimum unit observations determined.flood hydrograph of the basin is calculated using the computer program includes the geomorphological unit hydrograph analysis and convolution method that was developed in Fortran, to be come. K parameter values from the two methods show compatibility are close together.comparison of the hydrograph extracted from the model with the observed hydrograph corresponding to the respective tables GUHR can conclude that show little difference hydrograph simulated small arms and the observed values.This model reduces the time to reach peak flow and peak flow values very close to the observed values show that The parameter K of the mean basin unique optimal K event were calculated. Next, using an event, the model accuracy was assessed.The correlation coefficient 0/8 and returns 0/86. Indicate that the model is efficient. Parameter optimization as a unique medium Geomorpholozhic basin flood hydrograph model for hydrograph event, per the quantity and observations were compared to ensure the applicability of k. by varying the parameter k significant changes in peak flow rate, time to reach peak flow and hydrograph the overall shape was created.peak flow and time to peak flow increases with decreasing value of k decreases and vice versa. . So we can say unit Hydrograph sensitivity to change significantly the parameter k is quite logical.because the model only depends on the parameter k.Although the range of k for each event are presented that demonstrate acceptable performance. Conclusions GUHR model can reasonably predict the peak discharge this model can predict time to peak earlier than the time shown. In this model, the unit hydrographs are sensitive to changes in k parameter because changing the parameter k large changes in peak flow rate, reaching a peak and the overall shape of the hydrograph is observed.peak flow and time to peak flow increases with decreasing value of k decreases and vice versa. However, it can be concluded that the model GUHR is a parameter to be estimated, but for all the sub-basins of a fixed delay parameter, k is given. The main points to be noted that the performance of the model reveal that the model is largely due to the use of geomorphological characteristics of basin and have suitable capability to rainfall – runoff simulation.