javad chezgi

Considering the sensitive and fragile conditions of the ecosystems of arid and semi-arid regions, determining the contribution of factors affecting species diversity is of particular importance. In dry and desert areas, vegetation and species diversity are affected by topographical, edaphic and climatic characteristics The relationship between biodiversity and local environment is one common thread in biogeography and plant ecology. In arid regions, research in this area is very limited, species diversity patterns and species abundance distributions change in response to habitat heterogeneity in desert regions. One of the factors of heterogeneity in habitats of dry and desert areas is soil salinity. Soil salinity is one of the important environmental problems that causes problems for plants in different ways. This research examines the changes in species diversity with increasing altitude above sea level and changes in the soil properties in the west rangelands of Ferdows.

For this purpose, sampling was done from the lowest point of the region, the edge of the playa, from where the first species of Se. rosmarinus were observed, and the sampling was continued up to the heights of the summer rangelands, which was Stipa barbata type. Vegetation characteristics such as vegetation cover percentage, density, α and β species diversity indices and species abundance distribution (SAD) in each representative area were determined. At the beginning, middle and end of each transect, soil sampling was done (0-30 cm depth). The combined sample of each transect was transferred to the soil science laboratory of the Faculty of Agriculture of Birjand University, and the physical and chemical characteristics of the soil include EC, pH, N, K, Ca, Mg, Na, Cl, bicarbonates, organic matter, lime, gypsum, and soil texture and saturated moisture. It was determined using EC meter, pH meter, Kjeldahl, spectrophotometer, calcium meter, hydrometer and acetone and weight method. Also, the height above sea level of each transect was determined by GPS.The most important environmental factors affecting the distribution of plant types were identified by multiple regression analysis and PCA. Multiple regression was performed by backward elimination method. Before PCA analysis, centering and scaling were done on the matrix of environmental factors. Scree plot was used to determine the most important components. In order to determine the most important environmental factors with each of the PCA axes, Pearson's correlation coefficient was used. All statistical tests were performed by R software (R Core Team, 2021).

The results of this research showed that with the increase in elevation, the percentage of vegetation, number of species and species diversity increased. The results show that with the increase in elevation, from the first type to the last type, about 95% of plant species have changed. Multiple regression results showed that altitude had the highest effect on the vegetation cover percentage (β= 0.53). Gypsum and magnesium cause the presence of Se. rosmarinus. The results show that the general regression equation does not have the necessary validity, because the VIF values of some environmental factors are very high. After removing the environmental factors with high VIF, among the studied variables, only saturated moisture, alkalinity, magnesium, organic matter, nitrogen, lime, gypsum, sand and height remained in the regression equation. The results show that there is a significant linear relationship between environmental factors and vegetation percentage with a determination coefficient of 0.79 (p<0.001 and F: 6.13). Among the environmental factors, height above sea level was the only factor whose regression coefficient became significant and remained in the equation, and it also has the highest influence coefficient (β=0.53). Therefore, the height above sea level has the greatest effect on the percentage of vegetation Elevation and soil moisture saturation are effective in the distribution of Zy. atriplicoides and St. barbata in the mountainous. Also, sand is effective in the distribution of Ca. polygonoides and St. pennata.

According to the results, the vegetation properties and biodiversity show different reactions to the dominant environmental gradients of the study area. Also, the beta diversity is very high, indicating the severe variations in species composition from the beginning of the environmental gradient to the end of the gradient. One of the most important aspects of innovative and applied research is the phytosociological study of the study area for the first time, as well as the study of biodiversity and species distribution patterns. Therefore, the results of this study can be applied to planning rangeland reclamation and combating desertification.

In order to achieve sustainable land management, there is a need to comprehensively investigate the factors affecting soil erosion. If there are critical areas in terms of SE in a watershed, by accurately identifying them, it will be possible and reasonable to control and fight against erosion. This research, used Multi-Criteria Decision Making models include AHP, ANP, and BWM in the GIS environment to determine the erosion prone areas. First, the effective factors on erosion were determined based on the opinions and case studies conducted in the area. In the following, the desired data were obtained from relevant organizations, field observations, and previous datasets. In the next step, questionnaires on the impact of criteria on erosion were sent to experts, and after completing the questionnaires, the relative importance of criteria was obtained in Expert Choses and Supper Decision software's. Next, maps were prepared and combined. Finally, the erosion-susceptibility map of the region was obtained. The results showed that the geological formation factor had the significant effect on the erodibility with a relative importance of 0.23. In the following, the area was classified into five classes in terms of sensitivity to erosion, and the areas with high sensitivity have the largest area. The results of the MADM models used in this research were evaluated using the MPASIC experimental method, which all were suitable, so they are capable of determining erosion-prone areas.

Bandsar is a traditional large plot, which is built by creating an embankment on the level lines in the plains around ephemeral rivers, or is built across the waterways like small dams in the hill region, and directing and maintaining the flood or runoff of the hillslopes and uplands. So, it is a solution for harvesting rainwater in arid and semi-arid areas. Therefore, the purpose of this research is to locate and prioritize the suitable areas of the Bandsar in the watersheds of the Qaenat region to control floods, recharge the Qanats, wells, and springs in arid areas with the Best-Worst Method (BWM) and Geography Information System (GIS). In order to determine and locate suitable sites for the construction of Bandsar from 12 different criteria, including slope, distance from rivers, distance from villages, distance from Qanats, distance from roads, distance from faults, distance from wells, geomorphology, geology, permeability, available source, and land use has been used. Criteria were weighted using the BWM method, and the priority of each criterion was determined. Results showed that among the considered criteria, distance of river with a weight of 0.214 has the first rank, permeability with a weight of 0.151 has the second rank, and slope with a weight of 0.1123 has the third rank. The study area divided into 12 zones based on natural resource priority, that named the English alphabet (A-J). Finally, region B with a score of 0.63 is the best region and region J is the worst region with a score of 0.15.

In recent decades, the problems caused by the occurrence of droughts on one hand and destructive floods on the other hand, have led the country's water resources managers and those involved in the implementation of flood-spreading and artificial feeding plans. The use of water harvesting structures as one of the solutions to reduce flood damage along with the optimization of flood exploitation in the restoration of natural resources has been common for a long time in different parts of the world. Considering that by carefully designing and implementing these measures, the possibility of flooding and damages can be significantly reduced and the underground aquifers can be fed. In this research, the integration of geographic information systems (GIS) and the best-worst method (BWM) was used to determine suitable flood-spreading areas. Twelve influential criteria were identified based on the opinion of experts in the region for flood-spreading, and the weight of each criterion was calculated using the BWM, and the permeability criterion with 0.33 had the most impact on location. The information layers were prepared in the GIS environment for each criterion, finally, by combining the information layers, the entire region was zoned according to the weighted criteria. The results showed that most of the area is in a completely unsuitable condition with an area of 298,725 ha, unsuitable with an area of 21,000 ha, an average condition with an area of 14,300 ha, as well as suitable and completely suitable areas with an area of 45,811 ha. In addition, permeability, slope, and geology respectively with weights of 0.5, 0.186, and 0.13 have obtained the first to third ranks.

In the last decade, the migration of rural villagers and residents has made it clear that some villages are empty. In this context, the continued migration of rural residents to urban areas requires a review of lifestyles and incomes in the area, in order to be aware of the construction. Access to environmental problems and sustainable development depends on an understanding of the natural, social, cultural and economic development of a village and a careful planning and strategy in the field. In order to achieve the best strategic strengths, weaknesses, and threats the village was identified and characterized. In order to identify and characterize the best strategic strengths, weaknesses, threats and opportunities in rural areas. SWOT and ANP models were then used to assess the most appropriate strategies in decision-making and evaluation of the potential. The model results showed that aggressive competitive strategy is the best strategy. Based on the results obtained using the best network analysis processes to improve the lives of villagers and the potential new applications of public facilities such as greenhouse cultivation in the region. The SWOT model of strategy formation of cooperatives and the efforts and participation of locals in the production and sales strategies of government grants and self-educated class of his employment and occupation job with a score of 20 as the priorities of the Executive. Because many rural development activities in Iran are related to climate, the ANP models should consider the interactions among the factors considered in deciding the performance.

Flood is one of the most destructive natural phenomenon that occur worldwide, resulting in damage to properties, infrastructure, and even loss of life. This research aims to create a zoning map of flood-prone areas in the watershed of Khosuf County, using machine learning algorithms. In this study, 8 influential parameters and random forest (RF), boosted regression tree (BRT), and support vector machine (SVM) were used to identify areas at susceptibility of flooding in the study area. A total of 81 flood-prone zones were identified. Randomly, 70% of the data were allocated for the modeling process, and the remaining 30% were used for evaluating the generated models. The results of parameter importance analysis indicated that the drainage density parameter had the most significant impact on flood susceptibility. Furthermore, in determining flood-prone areas, the random forest model, boosted regression tree model, and support vector machine showed higher accuracy with receiver operating characteristics (ROC) curves of 0.99, 0.98, and 0.95, respectively. The study area was divided into four categories of flood susceptibility: very high, high, moderate, and low. Overall, the watershed is considered to have a moderate to high flood susceptibility level.

Placement of mountain Qanats in river alluvium is one of the reasons for the seasonality of these Qanat. Therefore, in the summer season, when the demand for water for agriculture increases, the water in these canals decreases or dries up. Underground dams are structures that block the natural flow of underground water, creating water reserves in the basement and increasing the water level in the wet period and use it in the dry period. It is believed that they will improve the flooding of canals in the summer. There is therefore a need to find suitable solutions for accessing new sources of water and its storage. The purpose of this research is to use an underground dam to feed the canals in the Taghenkoh Mountains area in Firouzeh city of Khorasan Razavi province. With this assumption, canals were prioritized for integration with underground dams using the analysis hierarchical processes method (AHP) and WASPAS decision making methods. First, the important and effective criteria in the construction of the underground dam were identified, and then the value of the criteria was determined using the AHP, and the criterion of the depth of the underground dam with a value of 0.32 was assigned the highest relative importance among these criteria. The site was prioritized based on the characteristics and relative importance of the criteria based on the WASPAS method, the Farang Qanat site was ranked first with a score of 3.01.

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.

Flood is one of the most important threats to human society, which has increased in recent decades with the increase in population and climate change. Therefore, studying the features of the basins that are related to the level of flooding can help to properly manage this risk. Nowadays, several methods such as morphological characteristics, This research was carried out using SWAT hydrological model in 21 sub-basins of Sarbaz watershed located in Sistan and Baluchistan province. After preparing the parameters and input data, while considering two years for warming, the model was recalibrated for a 17-year period from 1999 to 2016 and then validated during a five-year period from 2017 to 2021. The results obtained in the calibration stage were NS=0.76 and R2=0.86 and in the validation stage NS=0.56 and R2=0.58. The initial curve number parameter for medium humidity conditions and the alpha parameter in the return flow had the greatest effect in the sensitivity analysis. The results showed that sub-basin 20 with an average runoff height of 2.46 was ranked first and sub-basin 10 with a runoff height of 0.06 was ranked last. Based on the explanation and Nash-Sutcliffe, it can be concluded that the model has performed well in the simulation of Sarbaz watershed and can be used for modeling in the basin. Flood control by prioritizing flooding in sub-basins and by implementing management measures to improve pasture coverage and build watershed structures in the Sarbaz river basin has reduced the amount of flood discharge and prevented sudden damages.

Soil erosion is a serious threat to human well-being and life, especially in arid and semi-arid regions, and is one of the important issues in land management. Rill erosion is one of the most significant events in water erosion that affect soil loss, landscape, water resources, and land degradation can cause significant loss of soil in different climates. Identifying the effective processes that lead to the creation and expansion of rill erosion is necessary, and finding effective solutions to prevent rills is essential. In the meantime, one of the management solutions is determining the prone area to rill erosion. The high sensitivity of the lands of Nehbandan city (Kaji wetland watershed) to erosion is the reason for determining the prone areas to rill erosion. The maximum entropy method was used to identify the area that is susceptible to rill erosion.

The modeling process used 9 effective factors, including height, slope steepness, slope direction, rainfall, land use, land cover, soil texture, geomorphology, and geology, based on similar research. Factors affecting the occurrence of rill erosion were analyzed as independent variables. The first step in preparing a rill erosion sensitivity map was to determine the location of rill erosions in the Kaji wetland watershed using Google Earth and then to conduct field surveys. The basin was monitored in the field using GPS and 138 cases of rill erosion were recorded. The occurrence points were divided into two groups: training and validation, with a 70:30 ratio. The total occurrence points were divided into 97 incident points that were randomly selected for model training (validation stage) and 41 incident points that were used for validation purposes. The MaxEnt model relied on the data set used for training as independent variables. In order to use the maximum entropy model to determine rill erosion, first the independent variables (factors affecting the occurrence of rill erosion) and the dependent variable (identification of points with rill erosion) was converted to the required format and introduced to MaxEnt software. To evaluate the effectiveness of the model in detecting occurrence points (rill erosion) from pseudo-non-occurrence points, the area under the ROC curve was used. The Jack Knife test was utilized to investigate the identification and prioritization of 9 influential factors (independent variables) that influence the results. The model was implemented using the remaining variables as input factors after removing the independent variables separately for this purpose. The efficiency of the model built using all independent variables was measured in comparison to the case where the model was built based on other variables. To determine its effect on the output, the contribution of the omitted independent variable was examined.

According to the validation results, the sensitivity map for rill erosion has a high efficiency. The test stage should have a ROC curve of 0.859 (very good) and the test stage should have an average curve of 0.6 (moderate). The Jack Knife test revealed that the slope's steepness was the most significant environmental factor in the predicted sensitivity map for rill erosion in the study area. Geology and land cover were also recognized as other important factors. The MaxEnt model was found to be an effective model for preparing the rill erosion susceptibility map, according to the results. According to the findings, the slope steepness factor, which is 25%, is the main factor that affects the rill erosion of the Kaji wetland watershed. The high frequency of the slope class with a slope class below 20% suggests that this slope class is a significant factor in the development of rill erosion. The geological map of the region indicates that the majority of the region is dedicated to Quaternary formations, which is crucial for the development and creation of erosion in the region. The watershed's proneness to rill erosion is caused by poor rangeland usage. Management of vegetation and rangeland is necessary to reduce the potential for soil erosion in the region. According to the results, the soil texture of the region had less effect on the development of rill erosion; because most of the soil in the area is related to sand-gravel texture, which has a low effect on rill erosion. The MaxEnt model's high accuracy in modeling the sensitivity of rill erosion is evidenced by the results of the present study.

Protecting water, soil, and organisms, rangeland vegetation is naturally spread over the earth like an umbrella. On the other hand, vegetation changes either cause an improvement or irreparable damage to water and soil resources. Therefore, knowing the effect of vegetation changes on hydrological components of the watershed, including base and peak flow, is a prerequisite for any management planning at the watershed scale. However, the issue takes on particular significance in arid and semi-arid areas, where there is no sufficient quantitative data and the land cover and land use classes are widely dispersed. Therefore, this study sought to calibrate and validate a model for simulating runoff and sediment in the Sarbaz watershed using the soil and water assessment tools (SWAT). What follows presents a scenario concerning the simulation of the influence of improving rangeland vegetation on hydrological components of the Sarbaz basin using a recalibrated and validated model.

 This study used the SWAT hydrological model to investigate the effect of vegetation changes on discharge and sedimentation in the Sarbaz River watershed located in Sistan and Baluchistan province, enacting the scenario of improving rangeland conditions from poor to moderate. To this end, HRU was obtained from the combination of land use, soil, and slope class maps. Then, surface runoff, sediment, and chemical elements were calculated for each HRU, each sub-basin, and the watershed, respectively. On the other hand, ninety-seven hydrological response units were obtained based on digital height lines of 21 sub-basins after combining three maps. Then, following the preparation of the intended parameters and input data, the model was calibrated for 17 years from 1999 to 2016, and validated over a five-year period from 2017 to 2021. Finally, the model was implemented for the present time based on preliminary data, and then the scenario of improving the pasture conditions from poor to moderate was enacted to determine the influence of vegetation on runoff and sediment.

 The sensitivity analysis revealed that the alpha parameters in the return flow (v_ALPHA_BF) and the initial curve number of American soil conservation (CN-SCS) for medium humidity conditions exerted the greatest influence on the calibration and validation of the simulation. The results obtained from runoff calibration were found to be 0.76 Nash-Satkif coefficient and 0.86 explanation coefficient, and 0.53 and 0.58 for sediment, respectively, indicating acceptable rates for runoff (on a good floor) and sedimentation. Moreover, the results of the scenario concerning the improvement of pasture conditions from poor to moderate suggested a 46% and 15% reduction in the flood volume and total sediment, respectively, indicating the great influence of vegetation increase on Sarbaz River’s stability.

Preserving rangeland plants requires the protection of water and soil, and ultimately maintaining the balance of an ecosystem. However, quantifying the influence of vegetation on runoff and sediment requires modeling and simulation. Accordingly, the current study used water and soil assessment models to construct its intended scenarios. The area of poor pastures in the study area covers nearly 81% of the region. It should be noted that the status of the pastures could be improved through appropriate grazing methods such as modification and flooding, making the flow continue in dry periods and thus reducing the flood damage in the study area.
Generally, this study found that the average amount of surface runoff was decreased by 46.88%, indicating the effectiveness of the enacted scenario in reducing flood discharge. Moreover, the peaks of sediment in the diagram were decreased. Also, the average sediment was found to have decreased by 15.53% at the outlet of the basin, suggesting a significant reduction of sediment in the basin. Therefore, it could be argued that the scenario enacted in the current study worked well and that relevant organizations, especially the General Directorate of Natural Resources and Watershed Management of Sistan and Baluchistan province may play it out in the study area. Such a change could be made with suitable methods to improve the conditions of the pasture, including modification and flooding, leading to the continuation of the discharge flow in dry periods and the reduction in flood damage and loss of water and soil in the study area.

Watershed is the base of human societies interact with their surroundings, which have been affected by various problems. Accordingly, the evaluation of the stability of the watershed areas is inevitable. Considering the existing resources for evaluating and selecting a suitable method and quantifying the stability of the water, it seems a solution to select the appropriate method in evaluating the sustainability of the water. In this regard, to evaluate the sustainability of the Forg Watershed District in South Khorasan Province, based on the Help approach, aimed at determining the stability of this watershed area during 2006 to 2023. 12 variables were determined to investigate the stability of the basin and were based on the nature of the pressure, state and response indicators. The average privileges of hydrology, environmental, life and policy criteria were 0.238, 0.45, 0.50 and 0.57, respectively. The results showed that the stability of the area was classified by 0.40 on the low stability floor. The low stability of the watershed has caused any changes in the status of the watershed area to reduce stability and cause adverse conditions that will cause further destruction of the watershed. Therefore, it is suggested that the management and administrative policies of the Forg Watershed are in order to maintain the current conditions and promote the health of the watershed sub -areas, relying on the control of human activities and its related factors.

Flood is one of the most important threats to human society, which has increased in recent decades with the increase in population and climate change. Therefore, studying the features of the basins, which are related to the level of flooding, can help in the correct management of this riskWatersheds are different in morphological characteristics, so they have different hydrological reactions in the same climatic and environmental conditions. The stability of the morphometric characteristics of the sub-basins has made them used in flood studies. So that the investigation of the morphometric factors of the basins can be of great help to the management and prioritization of flood sub-basins.In this research, an attempt has been made to introduce and prioritize flood-prone sub-basin using morphometric data in the environment of the geographic information system in the north of Birjand Plain, using the maximum entropy method and VIKOR decision-making model.

Location of Birjand plain This plain is located in longitude 58 degrees 45 minutes to 59 degrees 30 seconds and latitude 32 degrees 30 seconds to 33 degrees. The area of Birjand Plain watershed is 3155 square kilometers, of which 1045 square kilometers are plains (33%) and the rest are highlands.In this research, morphometric factors (13 factors), entropy method and VIKOR decision making method were used to prioritize 22 watershed sub-basins in the north of Birjand Plain. Since the morphological factors of the aquifer basin have different effects on the processes of runoff formation, there is a need to determine the effects of the parameters, which Shannon's entropy method is used in this research. In the following, using the VIKOR method, sub-areas are prioritized.

Morphometric factors are important in identifying and determining flood risk areas. The effect of morphometric factors on flooding is not the same, so it is necessary to determine the importance of each parameter. Shannon's entropy method was used to determine the impact of different morphometric factors (14 parameters) on flooding in the northern Birjand plain watershed (Table 2, row 2). The results showed that the index of the Vf parameter with a relative importance of 0.51 had the greatest impact on flooding and prioritization, which is consistent with the results of Shirani and Chavoshi (2017), Rahmati et al. (2014) and Amiri et all (2017) does not match, and it is consistent with the results of Beheshti Javid et al. (2017) that different areas are different in terms of flooding and are influenced by morphometric factors and land cover. The indicators of channel maintenance and meandering index of the river had the least impact on the flooding of the sub-basins of the studied area.In prioritizing the flooding of sub-basins, all factors are not the same in terms of influence, so some factors have a positive effect and some have a negative effect on flooding, for example, the more the amount of drainage density increases, the more it has a positive effect and causes an increase in flooding. It is possible that if the parameter of the channel maintenance index is lower, the flooding will be more. This attitude and point of view has not been seen in many studies, but in this research, the nature of the parameters was determined based on the opinions of experts and previous studies. In this study, the increase of basin asymmetry indices, tissue ratio index, channel maintenance index, and valley width to height ratio index have a negative effect, that is, with their increase, there is less flooding, and other factors have a positive effect, that is, with their increase, flooding and runoff production also increases, which is consistent with the research of Esmaili et al (2016).

Watershed projects are one of the most important strategies for flood control. The implementation of watershed projects for flood control requires the determination of flood producing areas and their prioritization. Considering the lack of sufficient hydrometric stations at the level of the sub-basins and the lack of recorded statistics and information about floods in the country's watersheds, it is practically impossible to infer the severity of sub-basin floods from the available data alone. Therefore, it is appropriate to use methods such as morphometric factors that require less hydrometric and quantitative data. There are various methods for determining the amount of runoff and prioritizing sub-basins in terms of flooding, and most of these methods are based on graphical methods and the use of empirical formulas, statistical analysis of flood data, and basin separation. In this research, 14 morphometric parameters were used to prioritize floods in the north of Birjand Plain, because the morphometric characteristics of each watershed sub-basin is like its fingerprint, and it is possible to prioritize sub-basins for flood control based on that. In this research, subareas 9, 22, and 14 were prioritized 1 to 3, respectively, based on morphometric criteria.

The lives of both human and non-human societies are greatly impacted by healthy watersheds today. Improving watershed conditions can improve the lives of dependent communities, in addition to preventing the waste of water and soil resources. To improve the conditions, it is necessary to evaluate the available resources and choose a suitable method to quantify the health of the watershed. The PSR conceptual model approach was used to evaluate the health of the Forg watershed of the Madan city in this research. The fog watershed's health was determined by determining various variables after visiting it and identifying its problems. Subsequently, these variables were measured. In order to eliminate correlation between different variables, the VIF test was used to determine and remove correlated variables before implementing the PSR conceptual model. At the end, according to the remaining variables, pressure indicators, condition, response, and health of the Forg watershed were determined. According to the watershed health assessment of Forg basin, the pressure index falls within the range of 0.44 to 0.79. The condition index is in the range of 0.49 to 0.80, the response index is in the range of 0.20 to 0.69 and the heat index is in the range varies from 0.45 to 0.69. The pressure, condition, and response indicators have average values of 0.61, 0.67, and 0.43, respectively, and are classified as healthy and average. With a value of 0.57, the total health index falls under the average health category. The results indicate that the fog watershed is in a healthy state. To maintain the current situation and improve its health and performance, it is necessary to take proper management and executive actions, taking into account the influencing variables in each subwatershed.

Flooding and soil erosion are a significant issue in the watershed areas of Iran. The result of this is soil lost, soil fertility decreases, vegetation decreases, run-off increases, and severe floods. There are various watershed operations, including biological and mechanical, which protect water and soil, however, it is necessary to investigate which method and how many structures should be used in an area to be more effective. In this research, SWAT hydrological model and scenario building of watershed structures in waterways were used to investigate the impact of watershed management projects on erosion and sedimentation in Sarbaz River watershed, Sistan and Baluchistan province. After preparing the input parameters, the model was recalibrated for a 17-year period (1999-2016) and then validated over a five-year period (2017-2021). The results of the sensitivity analysis showed that the alpha parameters in the return flow and the initial curve number for medium humidity conditions in the SCS method had the greatest effect on the calibration and validation of the simulation. The results obtained from runoff calibration were 0.76 Nash- Sutcliffe coefficient and 0.86 explanation coefficient, and 0.53 and 0.58 respectively for sediment. The scenario's results have regulated the impact of watershed structures on nearly 15% of the sediment. Watershed measures are capable of reducing and controlling runoff, soil erosion, and sediment transfer in the region, as demonstrated by these results. In the meantime, attention should also be given to the financial issues of the plan when selecting watershed scenarios.

Bandsar is a traditional and Intelligently method of exploiting floods in arid and semi-arid areas, which can be implemented in a wide area with the participation of watershed residents. This structure, in addition to controlling floods and feeding the aquifer, expands flood agriculture in the region, and by collecting sediments from floods, it leads to soil enrichment. To this end, in this research, the structure and function of Bansadrs in the Shahid Parsa Dam watershed in the north of Sarayan city in South Khorasan province were investigated. First, using topographic maps and satellite images, the Bansadr's location was determined. Then, with field visits, measuring the dimensions of the Bansadrs, the way of construction, and land use, samples were harvested from the soil inside the Bansadrs. The results showed that Bandsars in the region are divided into two groups, mountain and plain, and according to their structure, they are divided into four types. Thus, the dewatering of Bandsars started in March, and usually, it is done two to three times a year. The time for land preparation and planting is from mid-May to mid-June. The amount of crop production in the years of relatively good rainfall is at least 3.5 t of plantation product and 1 t of fodder per ha, the average annual income is up to 6.11 billion Rials from all farms. The depth of sediments in Bansadrs varies from upstream to downstream and has a decreasing trend so that the thickness of sediments was 25 cm in one year in the beginning and less than 2 cm in the end dams. Therefore, Bansadrs can be suitable structures for flood and sediment control, flood irrigation, and soil regeneration in the region.

Floods occur in arid and semi-arid regions due to heavy rains and lack of vegetation which cause great loss of life and property throughout the world. Therefore, determining flood-prone areas and high-risk areas can be of great help in flood management and control. This study was conducted to determine flood-prone areas using multi-criteria decision making methods in Bagheran area of ​​Birjand City, South Khorasan Province. First, 10 effective parameters in floods were selected based on the opinions of experts and their relative importance was obtained using AHP and BWM methods. The results showed that the parameters of topographic moisture index and distance from waterway had the lowest score in both AHP and BWM methods, so that the rain parameter with relative importance of 0.265 and 0.137 had the highest score in AHP and BWM methods and had the highest impact. The zoning results were divided into five classes: very low, low, medium, high and very high. In both methods, high class had the highest area and very low class had the lowest area. The high class in the BWM method covers about 48% of the area, which can cause irreparable damage to residential areas downstream of Birjand.

The trend of river discharge changes in arid and semi-arid regions is mostly decreasing and this trend can be influenced by climatic factors and rising temperatures in recent decades in these areas. This reduction in discharge could have a significant impact on the water storage of the Nahrin Dam and agriculture, industry and drinking water in Tabas City, which should be considered by experts. The aim of this study was to determine the trend of discharge, precipitation and temperature in the watershed of Nahrin Tabas Dam using Mann-Kendall method, Sen's slope and linear regression. After data investigation and validation the data, the statistical period of 1987 - 2017 was selected. The results of all methods showed that the discharge decreased in all scales of annually, seasonally, and monthly. Precipitation has also decreased and in this 31-year period, it has annualy decreased by 0.8 mm, in average. The temperature has been increasing and on average, it has warmed up to about 1.5 °C during this period. The declining trend of river discharge has been due to climatic factors such as drought and rising temperatures. So that, according to the standardized precipitation index (SPI), the region suffers from severe drought in the last years. There is no water extraction for agriculture and industry above the hydrometric station, and the land use of the region has not changed. Therefore, declining trend of river discharge reduces  the agriculture and other exploitations at the downstream of the Nahrin Tabas Dam, which already exists.

Flood spreading schemes have been implemented in Iran to control floods, feed groundwater aquifers, improve vegetation, and increase pasture production. The proper evaluation of these projects is possible when the scheme is evaluated based on the opinions of residents and users. The purpose of this study is to evaluate the effectiveness of the Jajarm flood spreading from the neighboring villageschr('39') viewpoints. This study is an applied and field research in terms of control and supervision. The statistical community of this research is villagers living in the margins of the aquifer in the Jajarm flood spreading. The data collection tool is a questionnaire. To assess the validity of the questionnaire, the opinions of watershed management experts were used, and to evaluate the reliability of the questionnaire, Cronbachchr('39')s alpha was applied. The results show that the inhabitants of neighboring villages have positive viewpoints about implementing flood-spreading projects. Also, the outcomes show that the highest effect of flood spreading in villagerschr('39') opinion is in reducing the flood damages on residential buildings, farms, and gardens.

Controlling and managing of seasonal and sudden floods in arid and semi-arid regions, especially in areas where surface water is out of reach is necessary. Flood spreading is one of the best ways to control surface runoff and recharge groundwater resources. In the present study, the appropriate sites for flood spreading project in border area of Taybad county in Khorasan Razavi province is selected using Boolean logic .For prioritization the suitable locations, TOPSIS and VIKOR multi-criteria decision making methods were used. Firstly, using Boolean logic inappropriate areas based were removed on criteria (slopes greater than 8%, urban area, agriculture and covered pediment). Then, 11 zones were selected as the suitable areas of using TOPSIS and VIKOR models based on the criteria  of slope, groundwater quality, geology, alluvium thickness, transmission capability, drainage density, surface permeability, groundwater loss, distance from the village, distance from wells and land use.. Results showed that most suitable areas are located in alluvial fans. Based on the TOPSIS model, location J with value of 0.75 was selected as the best site, and using the VIKOR model, location K with a value of 0.96 was selected as the best location for flood spreading projects.

Evaluation of watershed management projects today is one of the most fundamental issues being addressed in countries for future planning in the field of natural resource management projects. The results of evaluating watershed projects by presenting a strategy and strategy should reduce future problems and costs. In this study, hierarchical analysis method and SWOT analytical model were used to evaluate and present the strategy. In this study 4 main criteria (reduction of erosion, flood reduction, increase of vegetation covers and increase of sewage discharge) and 8 sub-criteria were used. Then the final weight of each criterion and sub-criteria were determined using Expert choice software. The results showed that erosion reduction criterion with relative importance of 0.482 had the most impact on watershed projects. SWOT model results in the region indicated that the region's conditions were in the fourth quarter, WT or defensive strategy. To this end, strategies for mitigating threats and addressing regional weaknesses were presented using the region's potentials and opportunities, and prioritized using expert opinions. 8 strategies were identified and evaluated based on the potential of the area and the evaluation of implemented projects. The best management strategies to build coastal walls around the gardens in collaboration with locals with a final score of 0.28 were the first priority and a strategy to improve and increase the height of the dam overflow. Constructed with 0.02 points was the last priority.

Controlling and maintaining surface runoff for optimal use and recharge of groundwater resources is one of the important strategies in arid and semi-arid regions. Short earth dams are one of the least costly and most successful methods of flood control, water storage, groundwater utilization and sediment control. In this research, the Boolean model was used to locate these dams and the methods of network analysis process and VIKOR were used to prioritize it. In the first stage, using the Boolean model, inappropriate areas were removed and 43 potential areas were selected for the earth dam construction. Then using Google Earth and field views, 11 axes were designed to construct an earth dam in potential areas. Finally, these sites are used by network decision making process based on natural factors (rainfall, slope, geology, drainage and Erodibility) and socioeconomic factors (distance from city and village, distance from the road, distance from lending resources and water requirement), the results showed that the criterion of geology with relative importance of 0.472 had the most effect on the choice of dam axis. Finally, the 7rd place with a score of 0.115 in ANP method and 0.035 prominences in Vikor method was the first priority (Rank) for Earth dam construction.

Site selection is the first and most important stage in implementation of natural resources management projects. It can be effective in reducing the cost and timing of projects. The underground dam is one of the structures that reservoir is created in the underground, and its extraction depends on the topography and geology conditions of the area, so its location is very important from the hydrological, economic, and social points of view. In this research, the ARAS multi-criteria decision-making model and geographic information system (GIS) were used to select the most suitable sites for the underground dam construction in Kajbid-Balaghli Watershed, Garmah, North Khorasan. First, suitable sites were determined by using an exclusion method based on criteria (stream order, slope, geology, land use, fault, qanat, and spring). To prioritize suitable locations, water quantity criteria, water quality, reservoir slope, reservoir permeability, reservoir depth, reservoir surface, structural height, structural length, anchorage, water requirement, and access to the structures were used to determine the appropriate locations. The relative importance of the criteria was done using AHP method. Finally, the ARAS decision method was used to prioritize the suitable sites. Results showed that the water quantity criterion with relative importance of 0.23 and the criterion of underground dam anchorage with the relative importance of 0.02 gain highest and lowest score in views of the experts, respectively. The most suitable sites for the construction of underground dam was location A with Si = 0.36 and Ki = 1.