مجله مهندسی و مدیریت آبخیز
سال پانزدهم شماره 4 (زمستان 1402)

Managing a pervasive and effective phenomenon such as drought in different sectors of the economy requires close cooperation and careful planning. Lack of strategic drought planning and delays in decision-making have increased costs to reduce drought damage. The aim of this study was to develop strategic for drought adaptation using the SWOT model in Lorestan Province.

In this research, the methods of reviewing sources and interviewing with a questionnaire were used in order to provide macro strategies to adapt to drought. For this purpose, the current status of ecological resources, environmental changes, economic sectors and their dependence on water resources, population and employment, management of ecological resources, organizations and institutions were analyzed, then by reviewing the upstream laws and documents, interview with resource managers, local and national decision makers, experts, published background and other available information identified the causes of problems and obstacles to drought management in the province. The statistical sample consisted of 27 experts and scientific and executive experts were selected. Scoring was done on two occasions by experts, and finally, by averaging the opinions of experts and scientific and executive experts, the weight of internal and external factors was determined. In the final stage, in addition to identifying important factors in each of the criteria of strength, weakness, opportunity and threat, necessary management strategies were determined based on the conditions of Lorestan Province through SWOT analysis. These issues were categorized in the form of environmental opportunities and threats and internal strengths and weaknesses, then analyzed by SOWT analysis approach and Delphi method.

The study of strength factors shows that the existence of companies and organizations with resource monitoring units in the province with a weight of 0.25 has a higher effectiveness and degree of importance among other factors. Lack of proper planning and organization for monitoring and evaluation of drought weighing 0.33 has a very high effectiveness among the factors of poor adaptation to drought in the province. Among the opportunities, the factor of technological advances in the field of precision agriculture with a weight of 0.1 have a very high effectiveness. The factor of endangering the livelihood of farmers in case of drought is the most effective among the studied factors of threats with a weight of 0.22. Factors of irrigation of lands in some areas with polluted water and gradual destruction of agricultural soil and population increase and as a result increase in demand for water with a weight of 0.02 were recognized as having the least effectiveness among the threats of drought adaptation in Lorestan Province.

After scoring using the Delphi method, it was found that the presence of faculties and centers of agricultural education and natural resources in Lorestan Province was recognized as the most important strength. But despite this strong point in the province, unfortunately, the lack or inappropriateness of available data and information for the purpose of monitoring and evaluating the effects of drought is known as the main weakness. According to these results, in the direction of the conservative strategy, the strategy of balancing aquifers with the priority of aquifers with a negative water balance was suggested. The government's support for water harvesting projects at the level of cities and villages and the monitoring of better water management in cities provide suitable opportunities to improve the ability of farmers to deal with the negative effects of drought. The final result has been the presentation of drought coping strategies for different regions of the province in the areas of surface and groundwater supply, irrigated and rainfed agriculture, urban and rural drinking water and river water environment.

Soil erosion is the most important aspect of land degradation and one of the most important environmental, agricultural and food production problems in the world. More than half of the agricultural lands in semi-arid regions are under rainfed cultivation, and the tensions caused by erosion and destruction of land are important in terms of the effects within the field of erosion, such as soil fertility, and the effects outside the field, such as soil pollution. Information about the size distribution of eroded particles is a substantial step for managing the loss of nutrients and the transfer of pollutants from the soil. For this purpose, this study was conducted to investigate the particle size distribution of sediments resulting from interrill erosion under the influences of slope gradient and soil texture in some soils of the semi-arid region of Zanjan Province.

Toward this, four hillslopes having different soil textures (sandy loam, silty loam, sandy clay loam and clay loam) in four north-south slope percent (five, 10, 15 and 20%) were investigated using a simulated rainfall with an intensity of 60 mmh-1 for 60 minutes. In order to monitor the runoff and sediment samples from the beginning of the runoff until reaching a stable state, were taken at 5-min intervals from the initiation of runoff. The particles size distribution of sediment was determined by the method of particle separation using a series of sieves with diameters of 75, two, one, 0.5, 0.25, 0.1 and 0.05 mm. Also, the percentage of finer particles (silt and clay) was calculated by hydrometer method. Then the sediment particles are divided into eight categories: gravel (1-75 mm), very coarse sand (1-2 mm), coarse sand (0.5-1 mm), medium sand (0.25-0.5 mm), fine sand (0.1-0.25 mm), very fine sand (0.05-0.1 mm), silt (0.002-0.05 mm) and clay (<0.002 mm) were categorized.

The results showed that, with the increase in the slope of the land surface, the size distribution of sediment particles changed in all soils. So that, the transport of particles larger than 0.1 mm (including very coarse sand, coarse sand, medium sand and fine sand) increased with increasing slope. While the percentage of silt particles (0.002-0.05 mm) decreased in all textures. Also, particles with the size class of medium sand and fine sand formed between 40 and 50% of the sediment particles for each texture and did not change significantly with the increase of the slope. The highest ratio of particles in the sediment to the main soil was related to silt particles and in silty loam texture (4.33 times) and the lowest was related to clay particles and in silty loam texture (0.26 times). Sand and silt particles in different textures, had high transmission ratios. Silt particles in three textures of sandy loam, clay loam and silty loam had a ratio of more than one and clay particles less than one. Except in clay loam soil, sand particles changed in the range of 0.83 to 1.24 times compared to the main soil and the overall average ratio of its availability in sediment to original soil was 0.98 times.

In general, this research showed that with increasing slope, the selectivity of fine particles decreases and the share of coarse particles increases. The effects of these changes are more visible in fine-textured soils. Due to the increase in the destruction of aggregates and flow rate with the increase of the surface slope, it is very important to prevent the removal of vegetation and observe the principles of tillage in order to reduce the direct impact of raindrops on the soil surface and reduce the transportability of particles by the flow. Also, the results show that the ratio of particles in the soil texture and the characteristics of soil structure (abundance and stability of aggregates) are the determining factors of particle transport and it is necessary to consider these characteristics in choosing soil conservation methods.

Predicting changes due to climate change and its possible consequences on hydrological processes of the watershed helps to solve the challenges facing managers and water resources planners in the coming period. The effects of this phenomenon and gabion check dams simultaneously on the sedimentation of Dehbar Basin have not been studied so far, so the aim of this study is to investigate this with the perspective of the next 30 years, using SWAT and LARS-WG models and the ability of these two models to simulate climate change and remove gabion check dams.

In this research, the performance of gabion dams as a reservoir in the Dehbar Basin, 10 km west of Mashhad and south of the city of Torghabeh, which has a cold semi-arid climate, is compared to the amount of sediment output from the basin for the next 30 years with the LARS-WG statistical model and SWAT hydrological simulation model has been evaluated. There are five gabion dams in this area. To predict the meteorological variables of the upcoming period at the level of Dehbar Watershed, after recalibrating the LARS-WG model, the HadGEM2 model and three scenarios of RCP8.5, RCP4.5 and RCP2.6 were used for the microscaling of meteorological data in the period of 2050- 2020. Kolmogorov Smirnov (K-S), t and F statistical tests were used to check the performance of the simulation results in this model. To prepare and implement the SWAT model, the map and digital model information of elevation, soil, land use, hydrological and meteorological data were used. The tank was used to introduce gabion dams to the model. In order to analyze the sensitivity, calibration and validation of the SWAT model, SUFI-2 semi-automatic algorithm was used.

The average values of the simulated precipitation are in good conformity with the observed values and the biggest difference is related to the months of February and April. Regarding the standard deviation values of monthly rainfall, the biggest difference belongs to the months of February and March. The average simulated minimum temperature is also in very good agreement with the observed values. Also, for the maximum temperature, a trend similar to the minimum temperature is seen. Also, the p-value obtained from the t-test for the aforementioned variables, there is no significant difference between the average temperature and precipitation data produced and the observed data, and the LARS-WG model has been able to calculate the average temperature and precipitation very well. To simulate monthly precipitation in all scenarios (RCP8.5, RCP4.5 and RCP2.6) in the horizon of 2050 in the first seven months of the year is lower than the monthly precipitation in the base period, but an increase in precipitation is observed for the second five months of the year. Also, in the horizon of 2050, the temperature will increase on average compared to the base period. To draw the curve of the sediment gauge, the method of batch average with modified FAO coefficient was used. The amount of observed sediment was calculated as 2.14 tha-1yr-1. For the calibration and validation of the SWAT model, at first, using CUP_SWAT software, the parameters that had a greater effect on the discharge and sediment output from the basin were identified. In order to analyze the sensitivity, calibration and validation of SWAT model, SUFI-2 semi-automated algorithm was used. After that, the effects of climate change on the amount of runoff and sediment in the basin were investigated using the validated SWAT model. The results show a decrease in rainfall, an increase in temperature and a decrease in runoff in the horizon of 2050. The precipitation changes for RCP4.5 and RCP2.6 scenarios are +9.3% and +3.1%, respectively, and -4.6% for RCP8.5 scenario. On average, gabion dams reduce 57.09% of sediment exit from the basin.

In this research, the effects of climate change on the sediment output from Dehbar Basin in the period from 2020 to 2050 and the effect of gabion dams in the existing conditions (presence of dams) and in the conditions of removal of these dams were investigated. In all scenarios, the minimum and maximum temperature increased in the 2020-2050 period compared to the base period. One of the negative effects of temperature increase is change in the amount and time-spatial pattern of precipitation. The results indicate that the SWAT model is capable of simulating hydrological processes and sedimentation in relatively small to medium watersheds with complex conditions such as Dehbar Basin, even with limited observational data, with acceptable accuracy. The increase in the amount of sediment at the outlet point of the watershed, despite the decrease in rainfall and runoff, indicates short-term rainfall with high intensity, which increases the occurrence of flooding conditions. From the changes in the amount of erosion and sedimentation in the horizon of 2050 and with different scenarios, it can be concluded that the climate change will affect the erosion of the basin in the future and the simulation model can be effective in predicting the erodibility. Therefore, the results obtained from the SWAT model provide the possibility of recommending its use in the region.

The groundwater aquifer is one of the most vital resources, being considered more important in the countries (e.g., Iran) located in hot and dry areas. One of the ways to prevent contamination of groundwater resources is to focus on their vulnerability. So, a trustworthy assessment of groundwater vulnerability is useful to determine the contamination points of the aquifer for effective protection and management of groundwater resources.

In this research, DRASTIC index was applied to evaluate groundwater susceptibility while considering effects of land use and nitrate pollution for Kerman-Baghein Plain located in Kerman Province. In this regard, seven parameters including the depth of the water table, net feeding of aquifer, aquifer texture, surface soil texture, topography, impact of the vadose zone, and hydraulic conductivity were employed to calculate the DRASTIC index. It should be noted that this index has previously been applied by researchers for assessment of the vulnerability of the aquifer against groundwater pollution in different regions. However, despite the complexities in the underground water system and the opinions of experts in assigning the rank and weight of the parameters in this index and the difference in the conditions prevailing in the studied areas, it has always prompted researchers to take practical steps to improve this index. This improvement has been carried out in a number of studies by adding other parameters (e.g., land use and the effect of nitrate) to the parameters of the DRASTIC index. Therefore, in the present research, the parameters of land use and potential risk associated with land use have been used to compute the Composite DRASTIC index (CD) and Nitrate Vulnerability Index (NVI) in the Arc/GIS software environment, respectively. In this way, the CD index was obtained by adding the land use parameter to the DRASTIC index and the NVI index by multiplying the raster map of the potential risk rating related to the land use in the DRASTIC index. It should be noted that according to the land use map evaluation, this plain includes 54% of low-density pastures, 24% of irrigated agriculture, 10% of hand-planted forests, 6% of bare and desert lands, 5% of residential areas, and 1% of claypans. After the evaluation of three vulnerability criteria using all three indices DRASTIC, CD and NVI, their correlation with Ggroundwater Contamination Risk (GCR) was also investigated.

The results revealed that the correlation of the DRASTIC index with the risk of underground water pollution is 8%, the CD index is 30% and the NVI index is 54%, with a probability of 99%, they show a significant correlation. The results indicated that the addition of the land use parameter caused to increase the correlation of vulnerability with the risk of groundwater pollution, and multiplying the potential risk associated with land use led to further increase of the correlation. As a result, the NVI index was selected as the superior index compared to the other two indices.

The results of the NVI index of Kerman-Baghin Plain indicated that this plain is divided into two categories including very low vulnerability with an area of ​​1528.07 km2 (75.52 %) having an NVI value of less than 70 and low vulnerability with an area of ​​495.33 km2 (24.48 %) having NVI value from 70 to 110. Taken together, in order to properly manage the groundwater resources and prevent the pollution of these resources, it is recommended to prohibit the establishment of industries and the cultivation of agricultural sector causing the pollution in areas with low vulnerability.

Monitoring of hydrological droughts is one of the basic needs of water resources management in watersheds, especially in the field of water agriculture. Drought is divided into three major groups: meteorology, agriculture and hydrology. Hydrologic drought can be studied in different ways. One of the common methods is the use of low flow indexes and threshold level approach.

In this research, the minimum flow indices (Q75, Q90 and Q95) extracted from the flow continuity curve and minimum flow series (10 and 30 days) as well as the amount of flow deficit for hydrological drought monitoring in the Caspian Sea Basin were investigated and evaluated. For this purpose, 40 hydrometric stations with 41-year statistics (1970-2011) were selected. In the next step, the data of the studied stations were evaluated in terms of homogeneity, independence and randomness. Then, with the help of hierarchical cluster analysis and step-by-step regression, hydrological homogenous areas were determined and regional analysis of these indicators was done.

In order to investigate the characteristics of the minimum current in the Caspian Sea Basin, first, the continuous flow curve was drawn for each of the stations, and then, three indices Q75, Q90 and Q95 were calculated for each of the stations. For the spatial comparison of the minimum flow, the specific minimum discharge or qs (minimum discharge value divided by the area) was used. qs75 index varies between 0.0006 and 13 m3s-1per km2. The value of qs75 is less (drier) in the eastern parts and in the western parts of the region, the amount of dryness of the stream is less than other places. Examining the spatial distribution maps of these three indicators shows that the trend of their spatial changes is almost similar and they all indicate that the western regions of the Caspian Sea Basin are more humid than the eastern and central regions. In the next step, to examine the minimum flow indicators, a series of minimum flows of 10 and 30 days was prepared. By comparing distribution parameters with the help of scoring method, Log-Pearson type 3 distribution was selected as the best distribution in most stations. After choosing the most appropriate distribution, the values of the 10-day and 30-day minimum indices with different return periods were calculated. Examining the average indicators shows that the minimum discharge value of 10 days with a value equal to 0.01 m3s-1 in Vatana Station (12-035) located in the east of the basin and the highest with a value of 19.2 m3s-1, it is at Rudbar Station (17-034) in the western region of the basin. Regarding the average minimum discharge of 30 days, the lowest value is equal to 0.20 m3s-1 and the highest value is equal to 8.52 m3s-1in these two stations. In order to investigate the temporal changes of hydrological drought intensity, the annual time series of 10-day and 30-day low flow at each station were plotted in relation to the year of their occurrence, in order to determine the trend of changes in the drought situation in different years. Examining the time trend of the minimum flow indicators on the graphs, shows a decrease in the value of the indicators in recent years and a negative trend of the indicators. In other words, the graphs in almost all stations show hydrological droughts (reduction of minimum flow indicators) during recent years. In order to determine the length of minimum flow periods, 10 and 30 day moving averages of discharge were compared with Q90 index value in different stations. The results show that the persistence of drought in the central parts of the Caspian Sea Basin (Pulor, Razan, Karsang, Tange Lavij, Pol Zoghal and Zowat sub-basins) is more than the rest of the regions, these sub-basins are located in Mazandaran Province. The lowest duration of drought (between 22 and 25 days) is related to the sub-basins of Shalman, Pol-e-Sazman, Pashaki, Astana and Tutkabon in the eastern part of the Caspian Sea Basin and in Gilan Province. The eastern parts of the basin have also experienced a drought period between 28 and 30 days.

Results indicate that the years 1990 to 2010 have undergone severe and long droughts in most of the stations. The review of the spatial distribution of indexes shows better conditions in the western parts of the study area compared to the eastern sections in terms of dryness. However, the duration of hydrological droughts in the central study area is longer than in other parts of the basin. Investigating the time trend of the indexes also shows the increase in the frequency and duration of hydrological droughts in recent years. A comparison of different indexes shows that all of them have similar results in the region. The results of cluster analysis divided the area into three distinct homogenous units (in 0.01 significant level). The result of the regional analysis showed that in the eastern homogeneous region, the influencing factor on low flow indexes is elevation, while in the central and western regions, the drainage area and density have a greater impact.

Nowadays, the severe degradation of the environment and the reduction of the performance of watersheds are very important in order to respond to the various demands of human societies. In the meantime, in order to deal with these threats, the use of the approach of integrated management of watersheds as an infrastructure and acceptable management principles in the world community and based on conceptual and mental models has a special emphasis. The SWOT analysis has structural features and suitable flexibility that has a wide range of capabilities in managing different ecosystems. In the SWOT analytical model, strategies are formulated to maximize strengths and opportunities and minimize weaknesses and threats. Therefore, in this research, an attempt was made to evaluate the impact of various anthropogenic and natural factors on the status of Mikhsaz Watershed with the SWOT approach.

The Mikhsaz Watershed with an area of ​​11191.1 hectares is located in the west of Mazandaran Province and in Nowshahr City, Kajur district and Zanus Rostaq village. In terms of elevation changes, the lowest height is 1374.7 meters above sea level located at the outlet of the watershed and the highest is 3689 meters located in the southern. The average amount of annual precipitation in the Mikhsaz Watershed is 427.8 mm and the average annual temperature is 10.53 degrees celsius. SWOT analysis is one of the most efficient methods of strategic management which can be used for beneficial results in different study watersheds, analysis of local capacities and generally in order to achieve the goals of integrated development planning studies in economic, social, cultural and physical. The first step in strategic management is the establishment of the SWOT matrix. The SWOT matrix, considering the conditions, internal and external factors governing in a system that provides a good basis for developing approaches. In order to present the strategy in the framework of this approach, four types of strategies have been used, including competitive-offensive, diversity, revision and defensive. In order to provide any type of strategy, two or more components of the existing factors that cover each other or are related were considered. Then, in direction of these combined factors, the best strategies for the study area were determined and finally the factors were ranked. In the execution of SWAT strategies, by using the internal strengths, it is possible to make maximum benefit of external opportunities.

Two factors of income reliance on different sectors (livestock-agriculture-services) and climatic diversity (rainfall and temperature) in the watershed with a weighted score of 0.23 are usually the most important among the strengths. In the weaknesses, the factor of inadequacy of property compared to family members has been identified as the most important weakness of the watershed with a weighted score of 0.63. Two factors of the possibility of reviving handicrafts and nature suitability for tourism with a common score of 0.3, were the most important opportunities in the watershed. In this watershed, the possibility of spring floods caused by melting snow with a score of 0.2 and early and late cold temperatures with a score of 0.18 are among the most important threats. Therefore, internal factors with a score of 3.54 have a greater effect on improving the situation of Mekhsaz Watershed than external factors with a score of 2.89.

In this research, the impact of natural and anthropogenic factors on the management of Mekhsaz Watershed in Mazandaran Province was evaluated and measured using the SWOT model. The results showed that in the Mekhsaz Watershed, income reliance on different sectors and climatic diversity are the most important strengths and lack of property compared to the family members is the most important weakness. The prioritization of the region's strategies also indicates that the strategy of reducing the destruction of resources and modification of the livelihood pattern are ranked first and second with the scores of 2.21 and 2.19, respectively.

Predicting the maximum temperature changes is very important and has become increasingly important due to the many effects it has on water resources, agriculture and the environment. By forecasting the temperature, one can be aware of future changes and make the necessary arrangements to adjust its negative effects on water resources, agriculture and the environment. Therefore, modeling and forecasting the maximum temperature can be used as an important tool in the planning and management of natural, economic and industrial resources.

In this article, the maximum temperature was modeled using the Long-Short-Term Memory (LSTM) method based on Discrete Wavelet Transform (DWT) and Complete Experimental Mode Decomposition (CEEMD) methods in two different climates (humid and semi-arid). For this purpose, the daily data of maximum temperature, minimum temperature, precipitation, and solar radiation were used from 2001 to 2020 of the synopic stations located in Siyahbisheh, Amol City in Mazandaran Province and Urmia City airport in West Azarbaijan Province. It was determined that in the semi-arid region, the parameters of maximum and minimum temperature two days before, and maximum and minimum temperature one day before, as well as the minimum temperature and solar radiation of the same day, and in the humid region, the parameters of maximum temperature two days before, and maximum and minimum temperature one day before, as well as the minimum temperature and solar radiation of the same day were recognized as the superior model.

The results of the analysis of the models showed the capability and high efficiency of the method used in estimating the maximum temperature. On the other hand, the pre-processor methods improved the results. In the investigations, it was observed that the results of analysis based on wavelet transformation led to better results so that the DC evaluation criterion for the superior model in the semi-arid region of Urmia City went from 0.965 to 0.993 and in the humid area of Amol City increased from 0.926 to 0.970 and the RMSE criterion in Urmia Airport decreased from 1.943 to 0.896 and in Siyahbisheh from 2.595 to 1.648.

The results showed an increase in DC evaluation criteria and a decrease in RMSE for the synoptic station of Urmia Airport by 2.74% and 53.87%, respectively, and by 4.80% and 35.50% for the Siyahbisheh Amol Synoptic Station, respectively. This again shows that wavelet conversion has the greatest effect in improving the performance of the LSTM model and the selected models have high capability and efficiency in estimating the maximum temperature. According to the results of the sensitivity analysis, it was determined that the temperature parameter of the previous day is the most influential in estimating the maximum daily temperature for two regions with different climates (humid and semi-arid).

One of the important problems in the process of implementing and maintaining watershed projects and natural resources is the lack of effective participation and cooperation of watershed residents. Based on this, it is necessary and inevitable to pay attention to the inhibiting factors and also to identify ways to strengthen the participation of local communities in the process of implementing watershed and natural resources projects. This research, was done with the aim of knowing the socio-economic characteristics of local communities, identifying indicators that are effective in reducing obstacles and increasing people's participation in the implementation of natural resources and watershed projects, knowing the expectations and needs of the local community and finally, scientific and technical solutions have been presented to increase the level of public participation in Arpachai pilot area of ​​Zanjan Province .

In this study, four influential indices, including social-cultural, economic, natural, and managerial, were identified and categorized with 40 sub-indices. Necessary information was collected through surveys, questionnaires, interviews, and multiple sessions with community members and local experts. The sample size was determined using the Cochran formula, and the collected data were analyzed using SPSS software. Also, to check the validity of the questionnaire from Cronbach's alpha, factor analysis was used in order to reduce and categorize the variables affecting people's non-participation in watershed management projects.

The results showed that six factors explain 64.4% of the variance of the dependent variable and the education and information variable at the local level was recognized as the most effective factor that explained 29.97% of the variance of the dependent variable. Following that, the factors of improving the income and livelihood of villagers with 19.24%, diversity of economic activities and improving performance with 18.93%, strengthening the local economy with 13.92%, management of watershed projects with 11.34% and natural resources management with 4.3% were placed in the second to sixth priority, respectively.

In general, it can be said that the lack of information and awareness of the local community about the positive economic, social, natural and technical aspects and benefits resulting from the implementation of natural resources and watershed management projects in the area of their living and production is one of the important obstacles in the lack of participation and failure to achieve the anticipated goals in the implementation of watershed and natural resources projects in the study area. Based on this, attention and emphasis on the issue of building trust and increasing the level of social trust in the General Administration of Natural Resources and Watershed Management plays a significant role in the process of implementation and success of projects.

One of the methods for estimating the amount of runoff resulting from precipitation is the use of hydrological models. The SWAT model is one of the widely used tools for simulating the quantity and quality of water at the watershed level. This model is a conceptual model that is capable of simulating large watersheds with different management scenarios. One of the major challenges of this model and many other hydrological models is the calibration of effective and sensitive parameters for estimating the amount of runoff. In general, calibration methods can be divided into two groups: manual and automatic. Manual calibration of a model requires the modeler to have a good understanding of the model's physics. On the other hand, due to the time-consuming nature, existing complexities and the development of new optimization algorithms, nowadays automatic calibration has gained more attention. Automatic calibration is based on three components: the objective function, the optimization algorithm, and the station information. The use of a single objective function in model calibration may lead to an increase in error in other aspects of the simulation. Scientific experience in single-objective calibration has shown that no single objective function, even with high efficiency, can accurately represent all the characteristics and properties of a watershed. Therefore, the use of an appropriate optimization algorithm to improve calibration results includes the use of multiple objective functions to identify a set of efficient solutions.

The study area is located in the western part of Iran, in Kermanshah Province, with an area of 5467 square kilometers. The minimum and maximum elevations in the area are 1275 and 3360 meters, respectively. The average precipitation in the watershed is about 505 mm, with the highest rainfall occurring in the months of November and Decemeber, and the lowest rainfall in the months of Julay and August. The main rivers in this watershed are Mark, Gharehsoo, and Razavar. In this study, the SWAT rainfall-runoff model was calibrated using the NSGA-II algorithm under three calibration scenarios. For model calibration, the first scenario used the NSE objective function, which focuses on maximum flows. In the second scenario, to focus on minimum flows, the logarithmic transformation of the simulated and observed streamflow series was used, and the NSE efficiency coefficient was adopted as the objective function, represented as LogNSE. The third scenario was a combination of the first and second scenarios, where the non-concordant objective functions NSE and LogNSE were used simultaneously.

The results of this study showed that based on the NSE evaluation index values (0.83, 0.74 and 0.83 for the first to third scenarios) and the model overestimation and examination of the flow graph in the first scenario, which showed a tendency towards higher flows, this scenario would be more efficient in estimating maximum flows. Additionally, considering the LogNSE evaluation index (0.69, 0.74 and 0.72 for the first to third scenarios), the second scenario with the LogNSE single objective performed better in minimum flows. However, the model constructed using two non-concordant objective functions aimed to achieve a balance and showed satisfactory performance in simultaneously estimating maximum and minimum flows.

In general, it can be concluded that if the objective of the study is to investigate maximum and minimum flows, such as flood or drought studies, single-objective algorithms will perform better. However, if the objective is to control the water balance and achieve satisfactory performance of a model in both maximum and minimum flows, a two-objective scenario with a non-concordant approach can yield better results compared to single-objective algorithms.

The most important problem in the development and construction of underground dams is the complexity of determining suitable areas for dam construction. This problem arises from the fact that many criteria and factors including social, economic, geological and hydrological criteria are involved in its proper location. Therefore, it is important to use methods that can determine suitable places for the construction of underground dams with high accuracy and with the least amount of time and cost. The construction of an underground dam is recommended as one of the solutions for water supply in arid areas where there is no access to usual sources, such as wells and permanent rivers, or they have few water resources. For this purpose, in the present study, the location of the prone areas for the construction of such dams has been investigated. The studied area is the Rodan Watershed in Hormozgan Province, which has a good potential for the construction of an underground dam due to its dry climate and special geological conditions.

In this study, the number of eight initial locations were identified as potential points for construction underground dam by combining digital elevation model, topographic features, geological and hydrological features in GIS. In the following, after forming the decision matrix using Vicor model, ranking, determining the index and selecting the smallest index as the best option were done. Finally, the options were sorted based on the values of desirability index, dissatisfaction index and Vicor index. Then, the best option that has the smallest Vicor index was selected.

According to the obtained results, the value of Vikor index (Q) was 0.0158 and 0.097 for sites 5 and 2, respectively, and that way, based on Vikor index, the first rank belonged to the site 5 and the second rank belonged to the site 2. Therefore, out of the initial eight locations, only two places were suitable spots and other suitable sites were rejected due to the distance from the centers of population concentration and agriculture. Rank one, located in the east of Ziarat Ali, is one of the best places to build an underground dam due to the hydrological and topographical conditions, including the fact that the slope in this site is less than five percent. The second priority, located in the north of Brentin district, was considered as a suitable option for the construction of an underground dam due to its location in the vicinity of a sparsely populated village where drinking water is supplied through a well. Among the criteria used in the present research, the criteria of water need, distance from the village, pH and EC parameters, and water quantity were the most important in the sites that have been assigned the first and second priority.

Examining the results of the reservoir surface factor in this research showed that the larger the reservoir surface, the higher the priority in locating this structure. In underground dams, unlike surface dams where the large reservoir surface is considered a disadvantage due to losses by evaporation, regardless of other factors, the best place to build an underground dam in a river is the canyons that have the maximum area of the reservoir in upstream. Looking at the axes selected in the current research, it can be seen that the highest priorities and the most valuable axes are selected in the quaternary formations, which can indicate the accuracy of the structure's positioning. Since the peak of water consumption in the region is in the spring and summer seasons, therefore, by constructing an underground dam in the proposed sites, part of the water shortage and crisis in the hot seasons can be compensated.