فهرست مطالب محمدرضا اختصاصی

 One of the most important features of any watershed is the threshold of the start of runoff, which can reflect the different characteristics of the watershed and is an important factor in identifying and determining the flood status of the watershed. Accurate estimation of the amount and duration of runoff due to rain events, followed by the starting point of the flood, is one of the main points of interest in hydrological studies of watersheds. The runoff threshold is the amount of effective precipitation that is required during a certain period of time at the level of a certain watershed to start a flood at the outlet of the drainage channel of that level. The purpose of this research is to determine the minimum rainfall, or in other words, the effective rainfall on the start of runoff, in the Sanij watershed in the province of Yazd. By determining the height of the minimum rainfall for the start of runoff in the mentioned basin or other basins, one of the main and effective components in studies related to flooding and flood risk zoning is provided.

 The study area in the current research is the Sanij watershed, 30 km from Yazd city in Taft city, Yazd province, with an area of 153.173 square kilometers and geographic coordinates 31°32°48 to 31°18°42 north latitude and 36°54° north latitude. 53 to ˝54 ˊ03 ° to east longitude. Its annual rainfall is 220 mm, the average annual temperature is 11.2 degrees Celsius and the average relative humidity of the basin is 42%, the maximum height of the basin is 4036 meters and the lowest point is 2020 meters high. The concentration time of the area (Tc) according to the Bransby-Williams method is 5.18 hours. The stations targeted in this research are the Faizabad hydrometric station at the outlet of the Sanij watershed to provide flood discharge data, the Bidakhoud rain gauge station for hourly rainfall data and the Faizabad climatology station to provide 24-hour rainfall data. daily) whose data was available for the period from 1370 to 1400. To achieve the goal of the research, the relationships between maximum 24-hour rainfall and runoff threshold were investigated. Also, the compatibility of the corresponding hydrographs and hyetographs was studied in order to estimate the minimum rainfall for the start of runoff, and the intensity of rainfall was checked in the time base of 1 hour.   Then EXCEL software was used to analyze statistics and information.

 The results of investigating the relationship between the runoff threshold and the maximum 24-hour rainfall, whose data was a combination of 24-hour rainfall and torrential rainfall, showed that their function is y=0.9131x+ 14.01 and the minimum amount of precipitation with 82% of  R2 is equal to 14.01 mm. It also showed the results in the adaptation section of water patterns and corresponding rain charts; The average height of precipitation for the start of runoff is 18.9 mm. Finally, the average value for the minimum precipitation height in both study methods was 16.45 mm. Also, the intensity of precipitation in the time base of 1 hour was estimated as 13 mm; Therefore, if the intensity of precipitation is more than 16 mm in the time bases above 1 hour, it is expected that runoff will be produced at the outlet of the basin.

 The aim of the present research is to determine the threshold of effective precipitation that leads to the flow and start of runoff in a complete basin in the arid regions of central Iran..By knowing the threshold of the start of runoff in watersheds, one of the main components in hydrometric studies and optimal flood management is provided. The results showed that if the duration of rainfall in the basin is more than one hour and its amount is more than 16 mm, the runoff will flow at the outlet of the basin. It is also important to know the threshold of effective precipitation in the beginning of runoff in watershed plans, optimal use and management of precipitation, as well as the design of rain catchment surfaces to absorb precipitation. It should be noted that the results of this research depend to a large extent on the direction of the entry of rain-producing systems as well as its distance from the outlet of the basin, which is suggested to be investigated in future researches.

Providing good quality drinking water is one of the most important concerns of today's societies. Using a proper system for the fair distribution of potable water is very necessary and evidently the type of the system will lead to different amounts of water use per capita. Today, the dispute over good quality water resources in arid regions has escalated, Governments are forced to use separate drinking and sanitation water systems. Understanding the consumption of people in the form of per capita is a prerequisite for the proper design of drinking water distribution networks, the data of which are collected and analyzed in different ways. Quality of groundwater resources in Bajestan region, has led to the plan of separate drinking and sanitation water, with the establishment of government water collection stations since 2014. The purpose of this article is to estimate the per capita drinking consumption by query method by considering 378 samples and random sampling at certain distances from each station. The amount of per capita obtained is estimated at about 3 liters, but its amount has a different distribution in different city districts ranging from 2.5 to 4.5 liters. The highest amount is obtained for the new districts with villa texture and the lowest for the zones with more apartments. The results of the survey of the plan and the problems and consequences of its implementation showed that about 69.03% of people are using the water of these stations for drinking and tea, which is the criterion for determining per capita; The biggest problems of withdrawal stations are the numerous breakdowns of the stations and difficulty harvesting them, which requires the revision of some network operations.

In order to supply the drinking water for inhabitants of arid areas always have several challenges. The main source of fresh water supply in these areas is groundwater, but in recent years, increasing harvests and declining aquifers have increased salinity. Bajestan watershed is no exception of this issue and the main source of drinking water and sanitation is groundwater sources from the Playa, which is of very low-quality water. By decreasing the quality of groundwater resources has created the project to separate drinking water and sanitation by creating “The Government Drinking Water Stations”, since 2014. The purpose of this study is to investigate the rate of realization of this project implementation in order to quality drinking water supply. For this purpose, some of water samples was taken from the network and drinking wells, then the samples were compared with National and International standards and prepared the groundwater resources quality map.

In this study, at the first stage, the water samples taken from drinking wells and distribution network in the same period (2014-2019) were collected and compared with National and International standards. These standards included the standard of the Industrial Research Organization of Iran (1053 Report), WHO, the United States Environmental Protection Agency (EPA), the European Union (EU) and Schuler diagram. Then, Prepared the maps based on 1053 and Schuler diagram (The most common drinking water quality standards in Iran) which were selected by choosing the best interpolation method in the field of Geostatistical by choosing the lowest value of RMSE.

The results of this research showed that all of the quality parameters of distribution network’s water samples were within the standard condition, the values ​​of all the quality parameters were equal or even lower than the standard value of the indicators, So the conditions are optimal. While the water quality parameters in drinking water supply wells were of unfavorable quality according to the values ​​of the standards used in the research; These are EC, TH, TDS, Na, CL ​​in the water samples obtained from the wells on the Playa were 4 to 6 times and in other wells on the plain were 1.5 to 2 times the values ​​found in the standard indices. The results of the interpolation of the quality parameters of the plain's groundwater showed that the Co-Kriging method has the lowest Error in the main parameters of water quality determination, including EC, TDS and TH, which shows the high correlation of the parameters, there was a high correlation of groundwater in the plain with each other.

Comparison of the samples in the two parts of the wells and the drinking water distribution network showed that the current plan has sufficient usefulness to providing the quality the drinking water. Also, based on the map of the quality of the groundwater resources of the plain, the playa has the lowest quality of water resources and the wells located in the plain area have better quality.

One of the major challenges in arid regions such as Iran is the supply of water with appropriate quantity and quality. Drought, disputes over water resources, and providing good quality and quantity water for drinking, agriculture, and industrial sector, have forced governments to use desalination technology or transfer water among watersheds, Water desalination is one of the solutions to providing drinking water in Central Iran and coastal areas. Bajestan plain is no exception and has been using this method for about 16 years to provide drinking water and health for residents. Investors have recently been encouraged to build mineral water plants in arid areas; While the socio-economic and its environmental consequences are not yet clear. The results of this study showed that to supply fresh water from desert saline water with EC about 7500 (µs/cm) and reverse osmosis method with a production volume of 1000 (m3/yr), the price per liter of water is equivalent to 45.067 IRR. In this process, around 500 m³ of saline water and more than 6 tons of salt will be produced, too. This amount of salt will increase the salinity of the lands around the pistachio fields and orchards by 2 to 3 times and decrease the yields by more than 60%. Results showed if the bottles are not recovered, more than 18 tons of polyethylene will be produced. The economic evaluation shows that the value of the Net Present Value Index is negative and Internal Rate of Return is not acceptable, and the B/C is 0.46, which indicates that it is not economical to implement. Implementation of this plan in other arid regions with these conditions will have similar results.

One of the integrated water resources management requirements based on participatory management planning is identification and analysis of key stakeholders. Identifying structural aspects of organizational stakeholder's network can be evaluated using social network analysis and their position and role for inter-organizational integration and coordination in water resources management can be determined. In this study, using social network analysis method, stakeholders related to participatory governance of Abhar plain water resources, including 20 organizational stakeholders were analyzed and policy indicators were evaluated at the level of the network of organizational stakeholders. Indices of density, size, reciprocity, transitivity, centralization and geodesic distance in network of relationships at the macro level, core-peripheral index in the middle scale and centrality indicators at the micro scale of network were examined. Rate of network density index is moderate and according to index of reciprocity, moderate amount of bilateral and reciprocal relations among organizational actors, cohesion and organizational capital are assessed as moderate. According to transitivity index, stability and balance of information exchange network is low. Analysis of core-periphery index of stakeholder's network shows a higher density of links and greater organizational cohesion among central organizations compared to peripheral subgroup and amount of information exchange between central and peripheral subgroups was evaluated as moderate. Based on centrality indicators, geometric position of each actor in network was determined. For decision-making, planning, policy-making and participatory governance of water resources in Abhar Plain, key and effective organizations and political forces, as well as organizations with low power and marginalized, were identified.

Lack of rainfall, reckless grow of planting the agricultural products, uncontrolled abstraction of groundwater resources and lack of proper plans to reduce the adverse effects of the water crisis, has caused a sharp decline in the country's aquifers. The main objective of this study is to strategic management of water resources to determine the most appropriate management strategies for aquifer balancing.

Determining the most appropriate management strategies for balancing the Abhar plain aquifer has been done using the SWOT strategy formulation method. The most important internal and external factors (strengths, weaknesses, opportunities and threats) affecting water resources based on statistics and information collected, identified and after completing the questionnaire and survey, using group decision-making, the best strategy and applicable management approaches were explained.

The results of this study indicate that the weakness outweighs strengths as well as threats over opportunities. In other words, from the perspective of the experts present at the brainstorming session, the conditions of Abhar plain are in the quarter of weaknesses-threats (WT) with a defensive strategy that indicates the critical condition of Abhar plain aquifer in terms of the status of available water resources. Therefore, considering the current critical conditions of Abhar plain, the importance of optimal management, prevention of uncontrolled abstraction of groundwater resources, considering the most important weaknesses and main threats in this plain and the results of SWOT analytical model, the most appropriate solutions achieving the goal of balancing the groundwater aquifer of Abhar plain, are consist of focusing on land integration and preventing their fragmentation through integrated pressurized irrigation systems, changing the type of cultivation, irrigation method, benefiting from suitable climatic conditions for species cultivation low water demand, suitable geographical location in order to develop low water demand industries and equip water wells with smart meters to control and manage consumption. On the other hand implement watershed management and artificial recharge measures to prevent floods and loss of water resources and surface runoff harvesting was determined to control, manage and optimally use surface water resources and reduce abstraction from groundwater aquifers.

Using the capacity of opportunities and strengths ahead, Abhar plain aquifer strategy can be upgraded to ST strategy as well as WO and will be controlled the decreasing trend of Abhar plain aquifer volume.

Due to the low annual precipitation rate and, therefore, the existence of a weak and fragile ecosystem, arid regions are more subject to drought. Moreover, significant fluctuations in the temporal and spatial distribution of precipitation make drought forecasting in these areas a complicated task. Having a dry and fragile climate, Yazd Province has experienced numerous droughts within the past few decades. Therefore, it is highly important to monitor and forecast drought in this region. Population growth has increased water demand. Moreover, the increase in the concentration of greenhouse gases due to rising fossil fuels consumption has caused global warming and climate change, changing the hydrological cycle components including precipitation patterns (snow and rain). Therefore, climate change has changed the frequency, severity, and duration of droughts in many areas, especially in arid and semi-arid regions. So far, several indices have been developed to assess drought. This study used the RDI, which is based on precipitation (as system input) and potential evapotranspiration (as output), to estimate the drought. Furthermore, there are several methods for forecasting drought, among which projections of global climate models derived from greenhouse gas emission scenarios are quite common.

This study sought to analyze the efficiency of global climate models in predicting drought in arid regions (Yazd Synoptic Station, Yazd, Iran). To this end, 1961 to 2005 was selected as the base period, RDI values of which were imported to downscale the model (SDSM). Moreover, 2006 to 2018 was selected as the forecast period whose data were not imported to the model. Finally, the predictions of the model for the period 2006 to 2018 were compared with the observed RDI values of the same period for time scales of one, three, and six months. Accordingly, first, the climatic data collected from Yazd Synoptic Station (minimum and maximum temperature, relative humidity, sunshine hours, and wind speed) were prepared, and then the potential evapotranspiration (PET) was calculated for the period 1961 to 2018 via FAO-Penman-Monteith method. RDI value for the period 1961 to 2018 was then estimated on a monthly basis.Moreover, to predict drought through global climate models, CanESM2 global model forecasts were obtained based on the RCP8.5 greenhouse emission scenario from 2006 to 2018 for monthly precipitation, minimum temperature, maximum temperature, average temperature, sunshine hours, wind speed, and relative humidity. Using SDSM statistical downscaling model, the observed data for the period 1961 to 2005 and the projections of the CanESM2 model for the period 2006 to 2018 were downscaled. On the other hand, the mean surface temperature predictor was used to a downscale minimum and maximum temperatures and sunshine hours. Wind speed and surface-specific humidity predictors were also used to downscale wind speed and relative humidity outputs, respectively. Furthermore, to increase the accuracy, three predictors of precipitation, surface specific humidity, and mean surface temperature were used to downscale precipitation outputs. Finally, as for the high spatial and temporal variability of precipitation in arid regions, possible biases in precipitation data were corrected using the Linear Scaling bias correction method, which is based on the average difference between monthly observed time series and GCM historical simulations time series over the same period of the observed series. These differences were then applied to the future GCM simulated climate data to get bias-corrected climate variables.

The results obtained from the application of the FAO-Penman-Monteith method indicated that the variable trend presented by PET values during the study period was mostly induced by changes in wind speed fluctuations. Moreover, downscaled precipitation values showed a more significant error rate than those of the downscaled temperature outputs, probably due to the fact that precipitation values had more variability than the temperature ones, especially in arid climates. On the other hand, the application of the Linear scanning bias correction model showed that the precipitation values downscaled by SDSM for the base period (1961-2005) were overestimated compared to the real precipitation data over the same period. Therefore, the overestimation was corrected using the Linear scanning bias correction method. After correcting the probable precipitation biases and calculating the RDI index, the results suggested that the use of the Linear scanning bias correction model remarkably increased the accuracy of CanESM2 precipitation outputs.Then, the RDI was calculated by replacing the predicted precipitation and potential evapotranspiration values with the real data in the period 2006 to 2018 by measuring the potential evapotranspiration based on the data mentioned. Accordingly, R2 between real RDI values and the CanESM2-extracted forecasted RDI values for the 2006-2018 period was 0.472 for the 1-month time scale, while R2 was 0.738 and 0.762for for 3 and 6-month time scales, respectively.

The results indicated that the model presented a good performance at 3 and 6-month timescales. Moreover, considerable fluctuations in one-month precipitation values resulted in high variability of the one-month RDI time series, decreasing the model's performance at this timescale. Therefore, for projecting precipitation in arid and hyper-arid zones, a bias correction method should be applied to minimize probable biases. Furthermore, the comparison of actual droughts that occurred from 2006 to 2018 with the values ​​predicted by the model at 1, 3, and 6-month time scales showed that the CanESM2 model predicted the drought patterns with relatively good accuracy at 3 and 6-month timescales. However, as for the one-month timescale, the model presented lower efficiency than the other two time scales due to more fluctuations. Therefore, it can be concluded that GCM forecasts have a relatively acceptable efficiency for long-term drought prediction in arid climates.

Since there are not enough tools to measure flood, erosion and sediment in many watersheds of the country, it is necessary to use indirect methods such as fractal geometry to estimate them. There is very little accurate information about erosion in our country (Mohammadi et al. 2008). Understanding the sedimentation status and sedimentation of basins provides an accurate understanding of erosion and its consequences (Piri et al. 2005). Some parameters of watersheds have a special geometric shape that can be examined with fractal geometry. Mathematically, the basins that have the same fractal dimensions are equivalent to each other and are very similar in terms of geomorphological and hydrological characteristics (Adl and Mehrvand, 2004). The aim of this study is to obtain a significant relationship between fractal drainage network and erosion and sedimentation rates, and to generalize the results to unmeasured areas. 2. Introducing the studied area The studied area consists of 12 basins of Ilam province, which are in the western foothills of Zagros Mountain. Figure 1- The position of studied basins in the country and in the Ilam province Table 1- Specifications of basins and their stream gauging stations

These networks were provided based on 50DEM coordinates that in many cases, there isn’t enough accuracy and some channels are not displayed. Therefore, after transferring data to Google Earth, it was fully matched with the natural drainages and with a 5-meter accuracy, hydrographic network map was drawn and completed to reflect the full details of the network.Thence one cannot scale maps via “Fractalys”, fields with the same space of 25 kilometers on similar formations in different areas were accidentally chosen via “Fish Net” –in Arc GIS, to fix this problem. For each study formation, three 25sq.km. Fields were chosen and by the accuracy of 5 meters. These maps that had the same drawing accuracy and space, were drawn in the same scales via GIS on an A4 page in .bmp” and then were brought to Fractalys and finally, their fractal dimensions were calculated and extracted by the geometric method of counting boxes.

Figure 2- Hydrographic network and fractal dimension of the nazarabad watersheds before hydrographic network modification Table 2- Fractal dimension of watersheds before and after hydrographic networks modification In the following figures, the calculated fractal dimensions are observed for several samples of 25 km units before and after the hydrographic network modification. After the modification before the modification Amiran Aghajari 1.134 1.481 1.149 1.435 Figure 3- Fractal dimension of a hydrographic network of Aghajari and Amiran formations before and after hydrographic network modification. Quaternery Gachsaran Figure 4- Hydrographic network modification in the 25km unit on Google Earth Figures (3) to (4) show that after hydrographic network modification, the density of the hydrographic network and consequently the fractal dimension are increased in units of 25 km. Also, hydrographic network density changes in more sensitive formations are more than resistant formations, so their fractal dimension changes are also higher.Figure 5- Investigating the correlation of fractal dimension with hydrological indexes of Ilam watersheds the R2 value that is representing the correlation value is 0.0905. Therefore there is no significant relationship between the specific flood discharge of watershed and its fractal number. Table (3) Correlation test of specific flooddischarge data (Qw) in terms of (m3/s/ Km2) and fractal number (Fr) of the basins after modification of 25km units In Table 3, the specified number (-.240) indicates the correlation value of the data. Due to the obtained value, there is no correlation between the specific flood discharge and the fractal number of the basin.Figure 6- Correlation line chart of specific flood discharge data and fractal number of basins after modification of 25km un its Figure 7- Investigating the correlation of fractal dimension with the sedimentation index of Ilam watersheds In Figure 8, Due to the R2 value (0.939), it can be also concluded that there is a significant and direct correlation between the specific sediment discharge value and fractal dimension of the watershed. The following tables show the results of the calculations performed in SPSS software. Table 4- Correlation test of specific sediment discharge data (Qs) and fractal number (Fr) of basins after modification of 25km units The results of SPSS in Table (4) show that there is a high correlation between the specific sediment discharge data and fractal number. Because the number of 0.996 equals the correlation value between the two variables of the specific sediment discharge and the fractal dimension of the basins. The dispersion of data in the figure represents a high correlation in the data. Because the data are not scattered.

The fractal dimension gives more accurate results by the box-counting method than the magnification and radial methods..The results of the research show that there is a significant and inverse relationship between the fractal dimension of the formations and their resistance to erosion.As the strength of the formation increases, its fractal dimension decreases and therefore the density of the hydrographic network is lower.There is no regular trend between the hydrographic network density and the fractal dimension of the basin with the specific flood discharge of basins.Also, there is no significant relationship between this index and the fractal dimension of the basin.There is a significant and direct relationship between the fractal number and the specific sediment discharge (at a level of 5%), which indicates the erosion and roughness rate in the basin The highest value of fractal dimension can be observed in areas that are very sensitive, including Doiraj basin to 1.49.The least value of fractal dimension can be observed in areas that are resistant to semi-resistant in terms of geological formations, such as Kolm and Chamagaz equal to 1.14 and 1.11, respectively.

It is necessary to determine the appropriate probability distribution for fitting the flood data. There are several methods for estimating the parameters of probability distribution functions. In the present study, L-moments approach is used for flood frequency analysis in Gavkhouni Basin, Abarkouh- Sirjan Basin and Yazd- Ardakan Basin. Some stations were selected and their data were analyzed to find out peak discharge. Then, Hosking and Wallis homogeneity criterion were used to identify the homogeneous region. Examining the homogeneity criterion closely shows the discordant region. Eliminating and transferring some selected stations, leads to determining a homogeneous region of flood frequency. Parameters of the regional frequency distribution were evaluated using L-moment, moments, and maximum likelihood methods. The results of this analysis were compared using RMSE, R, and RRMSE statistics. The goodness of fit tests such as Chi-square, Kolmogorov-Smirnov were applied for checking the adequacy of fitting of probability distributions to the recorded data. The study reveals that the Pearson Type-3 distribution (using LMM) is better suited amongst the ten distributions used in estimating the peak flood. In general, the L-moment method estimated the peak flood for return periods of 10, 25, 50, and 100-year, and moments method at return periods of 2 and 5-year.

Digital elevation models and its derivatives are important factors for watershed modeling. It is obvious that DEM errors adversely affect the accuracy and thereby modeling of natural processes. This problem along with the impossibility of measuring all elements of nature, has led to a major evolution in the way of understanding and explaining phenomena. In this way, we can use the fractal geometry as a quantitative tool for modeling many complex natural phenomena. In fact, geophysical phenomena such as drainage networks are fractal phenomena with fractal behavior. The purpose of this paper is to evaluate sensitivity of the drainage networks based on DEMs (ASTER & SRTM), flow direction algorithms (Single Flow Direction (D8) and Multiple Flow Direction (MD8)) and topographic maps of 1:25000 in order to study the fractal dimension of drainage network on geological formations of Yazd-Ardakan basin. The results showed that the least difference in the length and the rank of the stream belonged to the drainage network obtained from the topographic maps of 1:25000. After the topographic maps, ASTER and the multi-flow direction algorithm are close to real ground map. Even though the multi-flow direction algorithm shows more detail on the drainage network. But it is not close to real ground map. The difference is particularly noticeable in the first rank of streams. Due to the very high sensitivity of the fractal dimension to the smallest change in drainage network conditions, the drainage network obtained from topographic maps were used to calculate the fractal dimension. The mean fractal dimension of 1.149, 1.16 and 1.207, respectively, represents Taft, Granite and Kahar formations. There is a significant correlation between fractal dimension and sensitivity to erosion of geological formations (level 0.99). In fact, the fractal dimension increases with increasing the sensitivity to erosion along with the drainage density in geological formations. The results showed that fractal dimension allows for a quick and accurate analysis of sensitivity to erosion of the formations of this area.

The increasing exploitation of groundwater reserves and consequently the drop in the water level and reduction of the reserves have seriously caught the attention of officials and planners to the integrated management of groundwater and surface water resources. The evaluation and management of water resources are considered as one of the key factors in comprehensive development. Boein Aquifer in Isfahan Province located in the Gavkhooni Basin is studied in this study. The Standard Precipitation Index (SPI), Reclamation Drought Index (RDI) and Groundwater Standard Index (GRI) in the time scales of three, six, 12, 24 and 48 months and Cultivated Land Index (CLI) in annual time scale are calculated. Results showed that the highest correlation between the SPI and GRI is in 18 and 24 months' time scale, and there is a delay of 1.5 to 2 years between these two droughts. Contrary to the results of some references, the correlation between meteorological drought index and GRI does not always increase with increasing the time scale. A synchronic study of the SPI, GRI and CLI shows a large difference between the SRI and the other two indicators in 2004-2008 periods that may be related to the poor management of the region. However, more close values obtained for these three indices in the recent years mainly due to the better management of water consumption by relevant organizations. To determine homogeneous drought regions, different combinations of temporal and spatial scales were used by creating 39 different scenarios and running 390,000 simulations. None of the heterogeneity measures were met in 90% of cases. This indicated that the linear moment technique is not a suitable method for determining homogeneous arid regions of groundwater probably due to the non-random data. Therefore, the linear moment technique will be more useful if the data is random.

In natural resources, economic evaluation is poor in terms of study due to the uncertainty of non-consuming value of resources. In the present study, the evaluation of water, soil and plant resources in watershed management projects and expert questioning was done to enable the projects to be evaluated and prioritized economically. Three sub-watersheds were selected from the Parcel A watershed of Gheshlagh Dam basin in Sanandaj, that the mechanical, biological and biomechanical operations in each of them was executed. The amount of water, soil and plant resources of each project according to the guidelines of Forests, Rangeland and Watershed Management Organization was estimated. The ratio of income to cost and the cost of each unit of resources were obtained by calculating the value of each unit of resources and calculating revenues and costs in each project. Then, water, soil and plant economics as criteria and watershed projects as sub criteria were determined with paired comparison matrix questionnaires. A project has priority that protects more resources at a lower cost than another. Questionnaires were distributed among experts and data were analyzed by Analytical Hierarchy Process. The results of the expert questionnaire and the valuation of the sources were compared. The results showed that, the cost per cubic meter of water in the mechanical project is higher than biological projects, although experts prioritize mechanical methods economically but biological with an income-to-cost ratio of 2.2 is the top priority .The cost of water in the mechanical, biological projects was respectively 1.4, 1.2 times the price per cubic meter of water in the area. Soil and plant prices were also calculated and the biological project became the top economic priority. Therefore, priority should be given to biological projects that have less cost and more impact on resources, contrary to watershed experts and detailed-executive studies. As well as the mechanical projects should be limited to areas in critical flood situations, provided that operate biological projects in upstream.

Today, various watershed management projects are being implemented in watersheds which sometimes, despite high study and cost, they are inefficient for various reasons and face economic failure. In the present study, first, different watershed projects in the Parcel A of Gheshlagh Dam in Sanandaj were evaluated. Then, their evaluation was examined by determining internal and external factors. The aim is to extract the most important factors and provide strategies that make projects economically viable and functionally effective. Weaknesses, strengths, opportunities, and threats of the region were extracted by experts and, using the SWOT analysis model and quantitative matrix of QSPM, economic-applicable solutions were presented. Results showed high value of management factors, so that the highest final value in external factors was inefficient study projects and the lack of funds for maintenance and repair of projects after implementation with scores of 0.50 and 0.43, respectively, and internal factors had the highest final value related to destruction and burial of dams due to the low quality of construction with a score of 0.59 which had the most impact on strategy selection. Based on the results of the model, the strategies are located in the ST quarter and are of a conservative method, in order to reduce the damage caused by threats and weaknesses by using the strengths of the domain. In accordance with this strategy, solutions were given by experts and prioritized by the quantitative matrix QSPM. The implementation of projects on land owned by individuals or the assignment of the right to maintain them to the owners with a final score of 8.76 was ranked first. The results of this research in the present economic situation of the country are very useful for informing authorities about how to optimize the implementation of watershed projects and will improve the instructions and implementation and the best use of projects.

Dust is one of the phenomena of atmospheric and natural disasters that poses adverse environmental effects and impacts. Due to the wide distribution of dust, this phenomenon can also change the soil and its biology trends. Typically, dust particles have a diameter of less than 100 microns, which can be transmitted horizontally or vertically to the ground after miles. The aim of this study was to determine the amount of dust falling and heavy metals lead and cadmium concentrations in dust samples to evaluate these elements is the urban pollution.

In this study, samples were collected using mild sediment trap for six months. A total of 180 samples were collected. Samples were weighed accurately using a scale of 0.001 g. The analysis of samples was performed using ISO11466. The samples were extracted by the Institute of Water and Soil Research, and the concentration of heavy metals was measured by the atomic absorption spectrometry of the Analyti jena-951 model.

The results showed that in the winter of March and in the spring of June, the highest rate of dust was observed. The mean lead concentration in winter was 97.32 ± 5.40 mg.kg and 90.16 ± 5.93 mg.kg in spring. Also, the average cadmium concentration in winter was 37.19 ± 3.60 mg.kg and 29.62 ± 2.42 mg.kg in the spring. According to the pollution index (PI), the level of contamination of lead is high in the floor, however, according to this index, cadmium contamination in both seasons is more than the level of contamination of lead and is higher than the limit, which is the risk index The ecology of cadmium, with an average of 1673.98 and 1333.03, also confirms this and is in the hazardous area of contamination. Also, the ecological risk of lead metal in winter was 18.14 ± 1.01 and in the spring with a mean of 16.91 ± 1.11 in the low pollution class. According to the values obtained for the pollution load index (PLI), this contamination rate is Cdwinte r˃Cdspring˃Pbwinter˃Pbsprin, and both of these elements are highly polluted in the classroom.

The results of statistical calculations and contamination levels indicate that the amount of dust pollution to lead and cadmium is higher than most of the calculated indices in the classes with high to high contamination.Therefore, these elements have been brought into the environment as a result of human activities and have less natural origin.

Drought is a natural hazardous phenomenon occurring in all climate types. However, it affects arid and semiarid regions more intensely than other areas. It also severely affects both the quantity and quality of water resources in arid zones. Moreover, land-use changes and urban and agricultural development also adversely influence water resources in these regions, especially groundwater resources.The extraction of a significant portion of drinking and agricultural water from groundwater resources has led to a sharp decline in groundwater storage in Iranchr('39')s arid and semiarid regions. Furthermore, as mentioned before, frequent droughts and land-use changes have affected these resources. This study, therefore, sought to investigate the effects of meteorological drought and land-use changes on groundwater quantity and quality in Darab plain, Fars Province, Iran.

Darab Plain is located in the south of Iran. The water supply in this plain is highly dependent on groundwater. The mean annual rainfall is 275 mm, and the mean annual temperature is 22 0C. In this study, data regarding precipitation, groundwater level, and salinity were used to estimate SPI (Standardize Precipitation Index), GRI (Groundwater Resources Index), and SECI (Standardized Electrical Conductivity Index). SPI is considered as the indicator of meteorological droughts. GRI quantifies changes in groundwater levels as a standardized index. SECI is applied to estimate any potential shifts in groundwater quality. Land-use maps of the basin for 2001, 2009, and 2017 were prepared using satellite imagery. Moreover, Landsat TM, ETM+, and OLI sensors were used. It should also be noted that land-use maps were created using the Supervised Classification method (Maximum likelihood algorithm). The produced maps included five classes: urban area, farmlands, gardens, rangelands, and bare lands.

SPI results showed normal classes for most of the years throughout the study period (-0/99 to +0/99). However, the trend line indicated an apparent decreasing trend for SPI during the period. Therefore, it could be concluded that the region is experiencing more droughts. A study of groundwater level changes suggested a continuous reduction of 36 m for the entire study period. While the comparison of SPI and GRI showed a general decreasing trend for GRI, it could be seen clearly that SPI changes caused GRI shifts. Moreover, droughts accelerate GRI reduction, and SPI growth either reduces GRI decreases or increases it slightly.On the other hand, SECI results indicated the salinity growth and quality reduction in the region. During the study period, the plain experienced a 293.6 µmho/cm increase in salinity. Furthermore, the comparison of GRI and SECI showed that any reduction in groundwater level would result in more saline. The comparison of land-use maps during the three years (2001, 2009, and 2017) also proved that agricultural uses increased by only 0.26% in 2009 compared with 2001. However, in 2017 compared with 2009, such uses decreased by 1.62%.The relationships between SPI and land-use changes with GRI and SECI were also investigated, indicating that droughts and land-use changes directly affect the quantity and quality of groundwater in Darab Plain.

Climate change has affected many parts of the world, changing drought characteristics in many regions. Therefore, the subsequent changes in water resources could be considerable. Furthermore, water resources are under pressure for population growth and land-use change. In this study, the collected data was divided into three 8-years periods (1993-2001, 2002-2009, 2010-2017), and the averages of SPI, GRI, SECI, and land-use were calculated for the three periods. The results showed that the increase in the severity of drought and the rise of the agricultural lands in the second period compared to the first one caused a decrease in water quantity (GRI decrease) and quality (SECI increase). However, a decrease in the severity of drought and the fall of the agricultural land-use in the third period compared to the second one lowered the rate of groundwater level decline (compared to the rate of GRI decreasing in the second period). In the third period, SECI increased (less quality) in response to the GRI decrease. The results showed that groundwater resources in Darab Plain were strongly dependent on both drought and land-use changes. The groundwater quality in the region was also directly affected by changes in groundwater level.

Seasonal floodwater has been kept in the lands by using watershed projects so that it penetrates into underground beds, but this case causes different influences on graining, permeability, underground water and vegetation. Three sections were chosen as experiment sites to measure soil changes of watershed projects in Nodoushan watershed area of Yazd province. Seven permeability experiments with double cylinder inside every section and three experiments in the control group were performed. Along with each of these experiments, one sample was collected from 0.5 meter of the surface soil and graining experiment was performed on it. The significance of permeability was investigated by the use of non-parametric Mann-Whitney test and Kolmogorov–Smirnov test. The results show that permeability in Sadrabad, Nodoushan and Alaviyeh in control group were 4.92, 3.52 and 5.89 cm/ hr, respectively. After some periods of dewatering they were reduced 94 percent, 89 percent and 92 percent, respectively. And finally reached to 0.28, 0.37 and 0.47, respectively. Also, the average diameter of the particles decreased about 90 percent. The results of experiments showed that the decrease of permeability was significant in the level of 95 percent.

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.

Given the reduction of quality and quantity of water sources in Yazd province, the consumption management approach should be considered. Separation of drinking water from sanitary water is one of the important components of quantitative and qualitative management of consumption. In the present study, scenario of dual water distribution network were evaluated in Gazorgah (old texture) and Safaieh (new texture) regions of Yazd province using EPAnet software in both technical and economic perspective. Investment costs of dual water distribution network in new and old texture are respectively 12595.1 and 20366.66 million rials. Current costs in new and old texture are respectively 736.80 (11.9% primary investment) and 1308.72 (6.4% primary investment) million rials. The cost of distributing each cubic meter of drinking water for dual water distribution network in old and new texture are respectively 113930 and 87630 rials. The results of economic analysis of the methods using Net Present Value (NPV) showed that both methods have positive NPV index, which shows the success of projects from an economic point of view. In relation to the comparison of the sales price of drinking water, the dual  water distribution network method in new texture with price of 46000 rials per cubic meter, relation to old texture with price of 60500  rials, has higher NPV and more economical. Estimated costs of dual water distribution network showed that in new texture was more costly than in old texture. The cause can be searched for in population density. As a result, dual water distribution network method is more economical in new texture. Because demand is higher in new texture. But since other parameters such as ease of access to drinking water distribution network, the age of the people, social acceptance is important, so in the old texture, dual water method is suggested. Therefore, by the implementation of this project, water conservation culture can be managed in a fair way through stable tariffs for drinking water and sanitary water rationing.

In desert area, limiting factors such as salinity reduce the diversity and density of vegetation and consequently reduce the use of these soils, which can make the most reasonable use of these natural substrates if proper management is implemented. Cultivation of species adapted to the region's conditions is one of the managerial corrective measures to achieve this aim. The present study done with the aim of investigating the economic and social effects and environmental welfare of the planting three species of Tamarix aphylla, Haloxylon aphyllum and Atriplex lentiformis and investigated the view of residents and resource management experts of Yazd and Ardakan as experts, in Chah Afzal village located on the edge of the Siahkouh desert, Ardakan, Yazd, Iran. The results showed that from the views of experts the cultivation of the mentioned species had no effect on reducing runoff and increasing infiltration of surface water whereas it had a high impact on ground water, soil, pests and diseases, regional vegetation and climate and also had a low impact on livelihoods, utilization and satisfaction. From the perspective of the residents it had no impact on pests, diseases, vegetation and utilization and had a significant effect on other parameters.

Specific climatic and geographical conditions of Yazd province have always exposed this region to a severe storm, and air pollution. Low visibility is the primary impact of air pollution due to atmospheric phenomena. Increasing dust density, along with a severe decrease in visibility, has harsh effects on the health of living things, socio-economic sections, and transportation systems. Therefore, identifying hazardous areas considering low visibility during dust events is important to manage and conserve the health of area residents. This study aims to evaluate the trend of changes in horizontal visibility of areas affected by dust storms in Yazd province, Iran. For this purpose, the quantitative model of horizontal visibility based on the relationship between Aerosol Optical Depth (AOD) of MODIS sensor derived from Deep Blue algorithm and horizontal visibility data derived from meteorological stations in the study area was introduced the horizontal visibility of dust events from 2015 to 2017 was mapped using geostatistics Kriging method. Results showed a significant relationship between aerosol optical depth and horizontal visibility data at the 99% level. The AOD value ranges from 0.1 in areas with no dust to 1.9 in areas with severe dust at six studied events, and the visibilities coincide with AOD values from 64 m in dust centers to 19951 m beyond these centers were estimated. Therefore, AOD image measures with more than 0.8 have horizontal visibility less than 1000 m. Determining of horizontal visibility extent without spatial limitation and identification of areas affected dust events are advantages of the quantitative model of horizontal visibility and its mapping. According to land cover/use map in Yazd province, mineral and constructing sites, high-density dirt roads, sand dunes, poor rangelands are the most effective factors in increasing of dust density and low horizontal visibility in pathways of dust storms of this province.

The drainage networks as the most prominent landscapes on earth are basis of many hydrological and geomorphological models. Due to the geomorphological properties of the region, the drainage network shows its own fractal properties that are saved as code in it. In fact, drainage networks are fractal phenomena with fractal behavior. Fractal dimension is a parameter used to indicate the complexity of data. The analysis of fractal dimensions of drainage networks and their morphometric properties facilitate the perdition of their behavior in the future. This paper focuses on the relationship between fractal dimensions of drainage networks and their morphometric properties of drainage networks in Yazd- Ardakan basin. Therefore, through an analysis of fractal dimension of drainage networks and its comparison with morphometric properties, the fractal behavior of these drainage networks are investigated. Results showed Pck and Ktl formations indicate highest and lowest fractal dimension respectively. The results indicated a significant relationship between fractal dimensions of drainage networks and morphometric properties. In this research, a positive relationship was observed between morphometric parameters and fractal dimension, so that the greatest correlation coefficient was found between the fractal dimension and the drainage density (0.99).

In this study, the quality of groundwater resources and their correlation with geology formation was considered. For this purpose, using the geological map of the area and geological formation were extracted. Then the qualitative data of 40 operation well and piezometer, to determine the water brigade was entered to the software chemistry. The following formations according to the type of production and the effects of quality, were classified; In the next step, buffers in intervals of 1, 3, 5, 7 and 10 kilometers was created around wells and layers were cut with geological maps. The results obtained using the t-test showed that at 95%, at 1, 3, 5 and 7 kilometers of wells, The impact dissolution of formation on operation wells, is significant but at a distance of 10 kilometers and with increasing distance, this effect was less and significant effect there is not in this respect, But their total impact of non-Quaternary on the wells increases. The results of the Boolean logic also showed that the Qt2 Formation has the most expansion in the proximity of wells, including alluvial fans and young alluvial sediments and are the main aquifer feeding site. But as the distance from the wells increases, the impact of non-Quaternary formations, such as Asmari Lime and the Gachsaran Group Formations, which have the potential to produce carbonate and chlorite types, increases.

Quantitative description of valley profiles can help us to identify its geomorphologic and dynamic properties and a useful tool for separating the valleys created by various processes. In this study, the Longitudinal and Cross-sections of 15 valleys were investigated in three geological formations of Kahar, Taft and Granite. Fractal properties of valleys along with the mathematical functions and two Vf and Fr indicators were used to study valley morphology. The average of Vf index was calculated in Kahar, Taft and Granit formations 5.56, 3.52 and 1.38, respectively. Also, the average of Fr index in three formations was calculated 0.07, 0.20, and 0.17, respectively. The results indicated heterogeneity in the lithology and structural status of valleys. According to the results, the shape of the valley, from Kahar to Taft formation, is U profile to V-shaped profile. The results showed that less curvature profiles are fitted with linear functions and profiles with more curvature fitted with polynomial functions. In fact, the polynomial functions, especially the fourth order, have high ability in modeling the Longitudinal and Cross-sections of the valleys. Subsequently, multifractal analysis of cross-sectional valley, Using the general multifractal dimensions (Dq) and the technical spectrum f(αq), showed that these sections are transmitted from mono-fractal to multifractal. None of the valley sections in Taft formation has multifractal properties. In a number of Cross-section valleys of Granite and Kahar formations, the multifractal approach seems to be more appropriate. Because of the fractal parameters may vary depending on the locations.

In the current situation, we face the limited quantitative and qualitative water resources. We have no choice except to change the perspective towards consumption management. Separating drinking water from sanitary water is one of the components of the quality management of consumption. Two senarios are water harvesting stations and dual water distribution network.The scenarios of separation of drinking and non-drinking water were analyzed using the EPANET software in Safaieh region. The estimated cost of the pilot region showed that the first method was more costly than the second method. The results of the economic analysis of methods of separation of drinking and non-drinking water using the Net Peresent Value (NPV) showed that all methods have positive NPV index, which indicates that the projects are successful economically. In relation to the comparison of the sales price of drinking water, the first method, ie, plumbing to the home with a price of 4700 toman per cubic meter, is higher NPV and more economical than another method. But since other parameters such as the accessibility of people to the drinking water distribution network, the age of the people, public acceptance is important in selection of the best method of the separation of drinking water from non-drinking water. Dual water distribution network method is suggested. By implementing this project can be managed water consumption through the quota of sanitary water and correcting the price of drinking water.