ابراهیم یوسفی مبرهن

Flood is one of the natural disasters that leaves a lot of damage in nature. Planning to use seasonal floods, while reducing their destructive effects, provides a new source of water to the consumer. Floodwater spreading is one of the methods that provides the basis for the optimal use of floods. Among the limitations that threaten Floodwater spreading projects is the gradual decrease in the amount of water infiltration in the soil, which is mainly due to the blocking of soil pores due to the spread of small and suspended particles that are carried by the flood. Davudarshid Kouhdasht floodwater spreading research station has been built with the aim of controlling floods, feeding underground water tables and adapting different tree species in this Kouhdasht area. The most important problem of this system is the accumulation of sediments on the surface, which over time has reduced the effectiveness of the system. Davudrashid Kouhdasht Floodwater spreading research station is important because before the construction of this project, Kouhdasht city and Ab Bariki village were exposed to floods. The purpose of this research is to investigate the changes in water permeability in the soil at the Davudrashid Kouhdasht floodwater spreading station, and to compare these changes compared to the control area.

The Davudrashid flood distribution station in the coordinates 33 33 42ء north latitude and 47 41 03ء east longitude (area of about 23 hectares) is located in Kouhdasht plain. This project was put into operation in 1998.This station has 6 sedimentation ponds and 18 expansion channels. First, the scope of the project was determined on the topographic map and an area similar to the floodwater spreading area (similar in terms of climate and topography, soil) was selected as a control. In order to compare the permeability of the field soil with the control field, sampling was done from the soil inside the flooded strips (spreading area) and the land adjacent to the field where the flood does not spread (control area). 28 samples were selected from the Floodwater spreading field and 20 samples based on systematic-random method. In the field of flood distribution between 18 expansion channels, a strip transect was randomly used to measure permeability. The amount of infiltration was recorded using Double ring at time intervals of 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 30, 60, 80 and 120 minutes. t-Student test was used in SPSS software for statistical analysis of permeability data. Kruskal-Wallis test was used in SPSS software to compare the changes in water permeability in soil in different areas of Floodwater spreading due to flooding.

Examining the collected data shows that the final infiltration in the control area (12.4 cm/h) is more than the flood spreading area (9.2 cm/h). According to the standard infiltration table, both flood and control areas are in the medium permeability class and do not differ much from each other. The t-test at different times between the flood and control areas shows that there is a significant difference at the level of 5 percent between the water permeability in the soil of the flood and control areas at 1, 2, and 30 minutes. At other times, there is a significant difference between the amount of water permeability in the soil of the Floodwater spreading areas and the control at the level of 1 percent. The results of statistical analysis using the Kruskal-Wallis test at different times between the upstream, middle and downstream areas of floodwater spreading show that at times 1, 80, 120 and the sum of the times of the second hour, there is a significant difference in the level of water permeability in the soil of different floodwater spreading areas at the level of 5 and one percent. At other times, in terms of this parameter, there is a significant difference at the level of 5 percent among the areas of flood distribution. The final infiltration speed in the upstream, middle and downstream areas was 8.9, 7.3 and 1.8 cm/hour, respectively. According to the standard penetration table, all three broadcast arenas are in the middle penetration class and do not differ much from each other.

From the results of this research, it is concluded that the floodwater spreading operation has affected the pattern of water permeability in the soil (amount and speed) in the field of Davudrashid Kouhdasht floodwater spreading and has led to a decrease in the average permeability speed. Due to the accumulation of water behind Stacks (inside the arenas) before the exit of excess water from the valves, significant amount of suspended material has settled down and in general has caused a decrease in permeability, which is significant at the level of 1%. It can be concluded from the results of investigating the infiltration rate in different areas of flood spreading, the infiltration rate in the downstream of the floodwater spreading area is higher than the upstream and middle of the area. This conclusion shows that the upstream sedimentation has reduced the rate of water infiltration in the soil. In general, the results of this research show that flood spreading affects soil permeability and causes a slight decrease in soil water permeability over time. Also, the amount of this reduction is different in different areas of floodwater spreading and from the upstream to the downstream of the floodwater spreading area (due to less sedimentation), the rate of infiltration increases slightly, but according to the comparisons related to the final infiltration capacity, it was determined that the spreading area The flood and the control area are not much different in terms of infiltration, and from the results of this research, it can be concluded that after about 30 years of the construction of this system, the infiltration is still appropriate and fast, and we should not worry about such an issue in the coming years. The results of this research can be used for better management of floodwater spreading station on Davudrashid Kouhdasht aquifer.

In most regions of Iran, the requisite water for population and industry is supplied by groundwater resources. Drought is an important factor, which affects groundwater quality. Groundwater is a renewable, limited, and vital resource for human life, social, and economic development. It is a valuable part of the ecosystem and is vulnerable to natural and human effects. Recognizing the quality of underground water, as one of the most important and vulnerable sources of water supply, has been a matter of course in recent decades. The effects of corrosiveness and sedimentation in water supply systems, water transmission, and distribution can increase operating costs and also create negative effects on human health. Therefore, the science of water quality will remain an important issue for engineers and scientists for years to come. Many methods and techniques have been invented and developed to investigate the chemical quality of water. Excessive harvests and recent meteorological droughts have changed the quality of underground water, but so far no study has been conducted in the entire Sefid-Rud Basin area to investigate the quality and the process of its changes. Therefore, the purpose of this study is to investigate the chemical quality of Sefid-Rud water which is used for the industry.

In this research, the chemical quality of underground water sources in the Sefid-Rud Basin has been studied and analyzed using the results of the qualitative analysis of water samples in deep wells, semi-deep wells, springs, and aqueducts, separately for three periods and according to the common statistical period of 18 years (2001-2018). The analyzed statistics and information include the results of a complete chemical analysis of water and parameters such as electrical conductivity (EC) values, total dissolved substances (TDS), pH, cations (Ca, Mg, Na, and K), anions (Cl, SO4, HCO3, and CO3), Na, and sodium absorption ratio (SAR) have been investigated. Water used by industries depending on the type of consumption in different sectors should also have certain qualities and characteristics. In this research, the Langiler index, which is an index for Corrosion and Scaling, was used to classify water quality for industrial purposes. To this end, the chemical quality of water in terms of chemical balance and occurrence of corrosion and scaling phenomena of underground water was classified into three categories: sedimentation, balanced, and corrosive. The Langelier index was used to measure water quality for the industry.

In the statistical analysis of groundwater in the Sefid-Rud Basin, while determining the maximum, minimum, and average values of qualitative parameters at the level of the study areas, the trend of qualitative changes at the level of their aquifers according to the EC map of the groundwater, has been analyzed. In the whole period of 18-year statistics (2001-2018) in the Goltapeh-Zarinabad and Tarom-Khalkhal areas, the average values of EC and TDS are higher than in other areas. there has been an increasing trend in the Goltapeh-Zarinabad area during the three study periods. Among the cations, the calcium ion had the highest amount (except for Goltapeh-Zarinabad and Tarom-Khalkhal areas), followed by the sodium ion. The highest amount of Na ion was observed in the area of Tarom-Khalkhal, the highest amount of Ca ion was observed in the Divandareh-Bijar, and the highest amount of Mg ion was observed in the Taleghan-Alamot. HCO3 and then SO4 ions were the main anions in the entire statistical period and all the study areas. It followed a relatively constant trend in all the study periods. According to the qualitative classification of industrial water, about 67% of the samples have corrosive properties and about 32% are depositors.

The values of EC and TDS in the three statistical periods in the area of Goltapeh-Zarinabad had an increasing trend. The sodium absorption ratio (SAR) in the entire statistical period was 2.9% with a maximum in the Tarom-Khalkhal range and a minimum of 0.8% in the Manjil and Sojas ranges. It shows the maximum values of cations for Ca ions with 3.6 in the Divandareh-Bijar range, Na with a value of 5.8 in the Tarom-Khalkhal range, and Mg with a value of 3.8 in the Goltapeh-Zarinabad range. Besides, the maximum amounts of anions including HCO3, SO4, and Cl were in Astane-Kuchesfehan, Divandareh-Bijar, and Tarom-Khalkhal areas, respectively. Qualitative assessment of groundwater resources in the Sefid-Rud Basin area for industrial use based on the Langiller index shows that the changing trend of this index has been relatively stable in the three periods, and out of 360 sources in the basin, 241 are corrosive sources, 115 are sedimentary sources and four sources have had a balanced situation. The analysis of qualitative zoning maps for industrial purposes showed that the Astana-Kuchsefahan and Divandre-Bijar aquifers, the central part of the Zanjan aquifer, and the western areas of the Goltape-Zarinanabad aquifer have sedimentation characteristics and other aquifers have corrosive characteristics.

Gully erosion is one of the factors threatening the environmental balance and its stability and plays a prominent role in increasing the sedimentation capacity of watersheds and changing the hydrological characteristics of surface streams. The purpose of this research is to evaluate the effectiveness of the maximum disorder machine learning model in order to prepare a gully erosion sensitivity map in the Semnan watershed. Identifying the most important environmental factors affecting the occurrence of gully erosion using the jackknife method and examining the importance of each environmental factor in the study area by analyzing the response curves are other goals of this research.

This research consist of five main steps: the first step is choosing the study area, collecting and preparing maps of the effective factors, the second step is preparing the distribution map of the ditch erosion event, the third step is the multiple collinearity test with the index of the tolerance coefficient and the variance inflation factor in order to check the information overlap of the effective factors. and checking the importance of the factors, the fourth step is to implement the maximum irregularity or maximum irregularity model, prepare a zoning map of sensitivity to the event of gully erosion and classify it into five categories: very low, low, medium, high and very high, the fifth step is to evaluate the classification accuracy and validate the zoning map and Prediction of sensitivity to gully erosion.

According to the results, among the 23 initial factors or variables, the factors of the waterway slope length index, surface curvature, and waterway power index had colinearity or overlapping information, and in the next stages, they were removed from entering the modeling process, and modeling was carried out with 20 independent factors or variables. The gully erosion sensitivity map of the studied area showed that the southern and southern parts of the Semnan watershed are prone to gully erosion. Also, the zoning results obtained from the implementation of the maximum irregularity model indicate that the areas prone to gully erosion are in high areas, sensitive rock units (quaternary clay and marl zones), average annual rainfall, Eridesville soil type, ultra-arid climate, high drainage density classes, low slope, low lands without geographical slope, high topographic moisture index, pasture land use and low land surface texture are observed. Also, the maximum irregularity model has 91% and 89% accuracy in the calibration and validation stages, respectively, which in terms of efficiency is in the very good category for predicting gully erosion prone areas.

About 35% of the area of high and very high sensitivity areas resulting from the implementation of the maximum irregularity model include more than 90% of the ditches in the region. Also, the maximum irregularity model in the stages of implementation or development and prediction or validation with the area under the receiver operating characteristic curve with the values of 0.91 and 0.89, respectively, is effective in zoning and predicting the occurrence of gully erosion. This result will be useful for local managers and planners as well as executive experts in order to identify areas prone to gully erosion and determine the best implementation methods of watershed operations for soil protection approaches.

Due to the occurrence of periods of drought and increased exploitation of the aquifer, the expansion of agriculture and the increase in groundwater harvesting, the level of the underground water level has decreased in the Bijar-Divandere Aquifer, which is the result of the decrease in the level of the underground water level and the decrease the efficiency of the wells has increased. The aim of this research is to investigate the effect of drought on the quantitative changes of underground water resources using geographic information system and groundwater resource index of Bijar-Divandere Aquifer based on representative hydrograph. In order to carry out this research, the statistics of 25 observation wells during the period of 2017-2018 were examined. At first, statistical data was collected and after entering the data into the geographic information system (GIS) with interpolation method, maps of parallel lines and zoning of changes in the level of underground water, as well as from the water source index. The underground GRI was used to monitor the time of drought of underground water sources in Bijar-Divandere Aquifer. The results of the changes in the reservoir volume of Bijar-Divandere Aquifer showed that the deficit of the reservoir volume is equal to 11.5 million cubic meters. Also, the time monitoring of the drought of the groundwater resources of the plain with the GRI index has a downward trend towards drought during the twenty-year period, and the most severe groundwater drought in the year 2018 has occurred with an index of -1.97. The obtained results indicate that if the current management process continues, we will witness a sharp drop in the aquifer and irreparable damage in the next few years.

Due to the occurrence of drought periods and increased exploitation of the plain, alongside of the agriculture expansion and the rise in groundwater extraction, the level of the groundwater table in the Zanjan plain has decreased, which has resulted in a fall in the level of the groundwater table and a decrease in the efficiency of the wells. The purpose of this research is to investigate and Zoning of Temporal and Spatial of the depth, level and changes of the level of groundwater table of Zanjan plain, trends of depletion and annual changes and temporal monitoring of the drought (GRI) of groundwater resource of Zanjan plain based on the representative hydrograph.

In order to carry out this research, the statistics of 69 observation wells are analyzed during 3 time periods (2001-2008, 2008-2013 and 2013-2018). At first, statistical data is collected and after importing the data into the Geographical Information System (GIS), maps of iso-depth, iso-level and zoning changes of the groundwater table are prepared with the interpolation method. The plain hydrograph has been prepared to investigate the long-term changes and fluctuations of groundwater table, as well as to detect the periods of rise and fall of the water level, during the statistical period for the Zanjan plain. Long-term changes and fluctuations of groundwater table are also drawn in the Excel. The phenomenon of drought in the long term causes the reduction of water resources through the drying up of surface and underground streams. For this purpose, the GRI index has been used to temporal monitoring of drought of groundwater resources in Zanjan plain.

The results obtain from the maps of the iso-loss show that the highest level of groundwater in the first time period (2013-2018) in the northern part of the plain is 12.4 m, in the second time period (2008-2013) in the southern part and the eastern part of the plain has dropped by 9.4 m and in the third period (2001-2008) in the northwestern parts, it has dropped by 14.5 m. The hydrographs of the groundwater table illustrate that during the period of 20 years, the depletion of the Zanjan plain table is 12.9 m, which means that the water level has depleted by 0.65 m annually on average. This actually indicates the negative changes in the groundwater level in the studied area. The results of the changes in the volume of the Zanjan plain demonstrate that the volume deficit of the Zanjan plain is 705.8 MCM. Also, temporal monitoring of the drought in groundwater resources of the Zanjan plain with the GRI index shows a very descending trend towards drought during the twenty-year period.

Groundwater is the main source of agricultural needs, especially in arid and semi-arid areas; therefore, having a sustainable agriculture requires careful management and planning on how to use these resources, which itself requires sufficient knowledge about the spatial changes of the groundwater level in a certain period. In the present research, the investigation of the depletion of the groundwater table, especially in the piezometers of the northern and side parts of the Zanjan plain, shows that this water disaster (groundwater level depletion of about 13 m) is mainly due to the improper management of water resources and the increase in the issuance of permits for deep and semi-deep wells with 61% growth in the last two decades. The negative balance of the plain is so severe that even the good rains of the last few years have not been able to stop the process of lowering the groundwater table. It is recommended to prevent the continuation of the Zanjan plain volume decrease, to manage and control the exploitation of the wells and to prevent any over-exploitation, as well as to use the implementation and development of plain projects to supply the shortage of water resources and feed the plain.

In the study of the trend of dust storm index, the results showed that the study period of 2003-2007 in Semnan province has an increasing trend and has shown significant changes in the 95% confidence range, but the lack of significant changes in the last decade shows the effects of various events. In cross-cutting decisions in the field of dust in the region. The zoning of the DSI index changes in different regions of the province in a 15-year statistical period indicates that from the west to the east of the province due to the increase in the frequency of stormy days with moderate dust (MDS), dust has increased. The correlation between drought and DSI index in Semnan province showed that although DSI index increased during the period under analysis with increasing drought intensity and its correlation with drought during the 15-year period was not significant, but the pattern of DSI index is consistent with It is the pattern of the drought process. According to the results, it can be acknowledged that the dust situation has always been affected by climate, but the relationship between drought and the DSI index has always fluctuated with respect to droughts and wetlands. However, different climatic parameters are different and their impact is different. In addition to human activities, the main role of wind in the amount of dust or the existence of another source of dust should be considered.

The lack of surface water resources has caused the indiscriminate extraction of groundwater in many parts of the world. The sharp drop in the level of groundwater tables, and the investigation of changes in groundwater resources are very important in the planning and sustainable management of water resources in each region. The purpose of this research is to investigate the changes in the level of the groundwater table Ghorveh-Dehgolan plain, which is one of the most important and largest plains of the province. To this end, the statistics of 104 observation wells during three time periods (2001-2008, 2008-2013, and 2013-2018) were analyzed. At first, statistical data was collected, and after entering the data into the Geographical Information System (GIS) with the interpolation method, maps of lines of equal depth, and zoning of decreasing the level of groundwater table were prepared. To investigate the long-term changes and fluctuations of the groundwater level, the representative water table of the aquifer was also drawn in the Excel software. The results obtained from the maps of the same area of the fall showed that the highest level of groundwater in the third time period (2013-2018) in the southern part of the aquifer was 7.3 m, in the second time period (2008-2013) in the central part of the aquifer has dropped by 5.7 m, and in the first period (2008-2001) in the northern and central parts has dropped by 3.3 m. The hydrographs of the groundwater level show that the water level has decreased by 13.8 m in the 20-year period, and the average water level has decreased by 0.7 m every year. The results of the reservoir volume changes showed that the volume deficit of the alluvial reservoir is equal to 56.2 million m3. In addition, the temporal monitoring of drought of the groundwater resources of Ghorveh-Dehgolan plain with the Groundwater Resource Index (GRI) has a downward trend towards drought during the 20-year statistical period.

Evaluating the implemented watershed projects and providing a perspective of their performance results provide managers and decision-makers with appropriate information for long-term planning. Nowadays, by using powerful remote sensing software and geographic information system, the necessary calculations can be done with more accuracy and speed. The purpose of this research was to evaluate the effects of watershed management projects implemented in the Rimeleh Watershed using geographic information system and remote sensing in terms of erosion, sedimentation, and runoff. EPM model was used to predict erosion before and after the implementation of watershed projects. American Soil Conservation Society (SCS) curve number method was used to calculate the runoff before and after implementation of watershed management plans. The CN coefficient was calculated for two applications prepared in 1370 and the current one. The paired t-test was used to investigate the statistical difference between the difference in production runoff and the amount of erosion and sedimentation before and after the implementation of watershed projects. The amount of total annual erosion and sedimentation in current conditions have decreased by an average of 6793 cubic meters and 5712 tons, respectively, compared to before the implementation of watershed protection plans. The amount of difference in the volume of annual runoff between before the implementation of the plans and the current conditions is on average about 15256 cubic meters. The results of the paired t-test showed that the watershed protection measures implemented in the Rimeleh Watershed have been able to create a significant difference in reducing erosion, sedimentation and production runoff, and the general conclusion is that these measures have had a significant positive effect in reducing erosion, sedimentation, and production runoff.

Marni Formations have little vegetation in most arid and semi-arid regions due to special physical and chemical properties. The establishment of coverage on them faced several limitations. To properly understand the state of ecosystems in arid and semi-arid regions, it is necessary to understand the dynamic relationship between vegetation and soil. The aim of this study is to identify the established plant species and to investigate the interactive effects of physical-chemical characteristics of erosion-sensitive marl and rangeland vegetation in marl formations in three regions (Taroud Roads, Bakran and Riabad) of Shahroud city; so that after delimiting the marl lands on topographic maps and using geological maps, soil sampling was performed to determine the characteristics and to measure the vegetation canopy. Moderate erodibility in Marni formations in three areas, Taroud Roads, Bakran and Riabad, was done using BLM model. The results show that in general, the erosion status by BLM method in Bakran region with the highest percentage of vegetation is in the lower class and in the area of Taroud Roads and Riabad is in the middle class. The results of correlation between physicochemical indices of soil and vegetation showed that the canopy factor was related to soil factors including gypsum percentage (CaSo4) and clay percentage at 99% and 95% confidence levels, respectively affecting each other. Clay in marl soil of Shahroud city is one of the most important factors that play an important role in the establishment of vegetation. The important point is that in all three regions, there is an abundance and predominant species of Artemisia plain and, without a doubt, this rangeland species can be considered as the most compatible plant species in the areas covered by marl formations.

Wind erosion and the movement of quicksands are considered as one of the important processes of land degradation and a serious challenge in Iran. In this study, an attempt was made to estimate the frequency of dust days in synoptic stations of Semnan province by considering the weather conditions. Also, the activity of sand dunes based on Lancaster index was examined. The results of this study during the statistical period of 15 years (2003-2017) showed Damghan station with 10% of erosive winds and 1058 days with dust and Shahroud station with 1% of erosive winds and 58 days with dust and Dust has the highest and lowest percentages of winds with speeds higher than the wind erosion threshold, respectively. The results of Lancaster index showed that Damghan city with the highest index has the potential of "fully active" wind sediments and therefore the stabilization of sand dunes is essential to reduce the damage caused by the activity of sand dunes in this area. The results of predicting the effects of possible changes in climatic factors on the mobility of quicksand in the selected station of the province showed that the sensitivity of sand mobility to changes due to increase in rain more than wind speed and to changes in decrease due to rain less than wind speed and if the average wind speed decreases by 30% in the future or the amount of rainfall increases by 30%, the condition of the hills will change from fully active to active.

Hydrological simulation of watersheds applies for estimating peak discharge and runoff volume from rainfall, flood routing in rivers and flood hydrograph analysis. The purpose of this study is application of soil moisture accounting (HMS SMA) and Neuro-fuzzy models in daily flow, The purpose of this study is application of soil moisture accounting (HMS SMA) and Neuro-fuzzy models in daily flow. runoff volume and hydrograph analysis of the simulated rainfall - runoff in the Zola Chay watershed. In this study after of Zola Chay watershed modeling with HEC-GeoHMS Extension, In this study after of Zola Chay watershed modeling with HEC-GeoHMS Extension. the model entered to HEC-HMS program and by parameters estimating of soil moisture accounting model, the rainfall- runoff simulation in other scales has been done. By analysis of time scales for calibration and optimization of HMS SMA model parameters we can claim that the monthly time scale rainfall - runoff simulation accurate than annual, seasonal, semiannual and annual time scales can be better than the other time scales of flow to estimate peak. Comparing the calibration and optimization soil moisture and Neuro-fuzzy methods revealed that fuzzy method can simulate rainfall- runoff relationship better than SMA model by best statistical coefficients (E= 0.76 and RMSE= 0.18).

Land use change due to human activities is one of the most important issues in regional planning and development. Damghan urban basin has in recent years undergone many changes of the sort, including intensely increased urban population, physical expansion of urban and rural settlements, and disappearance of green spaces converted into residential areas. These changes have resulted in many flooding and inundation events within the urban area. The satellite technology can be exploited to identify such changes and the areas affected. For the purposes of this study, use was made of the ETM+ images of 2003 and the OLI images of 2015 obtained from Landsat to calculate the inundation conditions in Damghan urban basin using the USISM method. The ETM+ results showed a kappa coefficient of 75% and an overall accuracy of 0.67% while those of OLI images were 80% and 0.74%, respectively. The images revealed that green spaces had been converted to residential and commercial sites at a rate of 28% in 12 years. Meanwhile, agricultural land was found to have increased during the same period but barren lands to have decreased.

Today soil erosion is considered a danger to human and life. In areas where erosion is not controlled, soils gradually erode and lose their fertility, so it is necessary to study the issue of erosion. According to a study conducted in the Masouleh watershed, there are two types of erosion intensity called type 3 or moderate erosion with an area of ​​28.15 km2, type 4 or high erosion with an area of ​​13.79 km2. The predominant forms of erosion in the region include mechanical, surface erosion, furrows, waterways and deposits. According to this study, the average amount of erosion based on Mpsiac method in this field is 4.81 tons per hectare per year, sediment delivery ratio (SDR) is 74.3 and the average amount of sediment in this field is 3.85 tons per hectare per year. It indicates moderate erosion and sedimentation in the whole area and high in some sub-fields. To control erosion and reduce production sediment in this area, various programs include holding training courses for people in dealing with nature, implementing management programs (including applying grazing systems, balancing livestock and pastures, development and medicinal plants), and conducting biological operations ( It has been suggested for rangelanding in the form of sowing, sowing, mulching and planting in a non-productive way) and mechanical operations (including the construction of mortar stone dams, gabions, dry land, etc.) have been proposed.

One of the methods used for calculating flood peak discharge in non-statistical watersheds is experimental methods. One of the empirical methods used in this study is the Fuller method which has advantages over other empirical methods for different flood periods. In this research, we have compared the linear programming optimization techniques and genetic algorithm in optimizing the fuller experimental formula coefficients in Excel and MATLAB respectively for selected watersheds of the region. For this purpose, the statistics of maximum 24-hour discharge of 9 stations in West Azarbaijan province with a statistical period of 21 years were studied. Comparison of the results showed the superiority of the genetic algorithm method and then linear programming. The results also show that the use of smart search methods improves the performance of conventional methods significantly. For this purpose, the statistics of maximum 24-hour discharge of 9 stations in West Azarbaijan province with a statistical period of 21 years were studied. Comparison of the results showed the superiority of the genetic algorithm method and then linear programming. The results also show that the use of smart search methods improves the performance of conventional methods significantly. For this purpose, the statistics of maximum 24-hour discharge of 9 stations in West Azarbaijan province with a statistical period of 21 years were studied. Comparison of the results showed the superiority of the genetic algorithm method and then linear programming. The results also show that the use of smart search methods improves the performance of conventional methods significantly.

There are several statistical and empirical methods for flood discharge estimation. One of the empirical methods that were considered in this study was fuller equation. The advantage of fuller equation in compression of other empirical methods is estimation of different periods of flood discharge. In the first step، hydrological missing data generated using. In order to continue to use empirical formula for estimating Fuller maximum instantaneous flow rate in different areas، users should calibrate coefficients of equation for each region. In this study، coefficients of fuller formula optimized using non-linear programming model by Lingo. The maximum instantaneous flow rate for the region was estimated to selected stations. The results show that، the regional coefficient (c) is 0. 19 and (ß) coefficient for return periods of 2، 5، 10، 25، 50، 100، 200 years are 0، 0. 93، 1. 16، 1. 38، 1. 53، 1. 68، 1. 84 respectively. Therefore، Fuller formula coefficients (2. 66 and -0. 3) was calibrated in significant level 0. 01 and correlation coefficient (R= 0. 95) for the study area. The results shows that the optimized fuller formula could have better fitting in the lower return period (2، 3، 5، 25 Yr)