نشریه مدیریت جامع حوزه های آبخیز
سال چهارم شماره 1 (پیاپی 11، بهار 1403)

Water and soil resources are the most important factors in the production of energy needed for humans. In order to protect water and soil resources, different management methods are applied according to the conditions of each region. The participation of all watershed residents and changing their behavior will be one of the basic tools of any sustainable management plan. Since norms affect the participation and behavior of local communities; the purpose of this research is to investigate the norms affecting the participation and behavior of watershed residents in the implementation of water and soil protection projects.

This research was done by descriptive-analytical method. For this purpose, Benchele watershed in Ravansar city was selected as the study area. A questionnaire was used to collect field data. The statistical population of this research was all heads of households of watershed residents in this area, numbering 569 people. Among them, using Cochran's formula and matching with Morgan's table, 229 people were directly questioned by simple random method and completed the questionnaires. Spearman's correlation tests and stepwise regression were used to analyze the data. The focus of the questions was focused on three independent variables (legal norms, normative beliefs and participatory norms) and two dependent variables (participation and behavior of watershed residents). In the data analysis section, descriptive statistics (frequency, percentage, average, etc.) and inferential statistics (Spearman's correlation test and step-by-step regression) were used. Before performing the regression to check the collinearity test, the degree of collinearity of the independent variables was examined. Also, standardized beta values were used to determine the relative importance of each independent variable in the participation and behavior of watershed residents.

The mean ranking results of each of the items of legal norms affecting the participation and behavior of watershed residents in water and soil protection projects show that the items of "people who damage water and soil resources should be fined" and "existing laws are useful to convince people in the field of protecting water and soil resources" have the greatest and least impact on legal norms with the participation and behavior of watershed residents, respectively. The results of the mean ranking of each of the items of normative beliefs affecting the participation and behavior of watershed residents in water and soil protection projects show that the highest ranking average is related to "society expects me to take care of water resources" and do not destroy the soil" and the lowest rating is related to "experts expect me not to destroy the soil". The mean ranking results of each items of the participation norm effective on the participation and cooperative behavior of watershed residents in water and soil protection projects show that from their point of view, the item "voluntarily participates in the construction of sediment dams" and the statement "I am willing to pay for the implementation of water and soil protection projects", respectively, have the greatest and least impact on the participation and behavior of watershed residents in water and soil protection projects. The results of Spearman's test showed that all three independent variables of legal norms, normative beliefs, and participatory norms have a positive and significant relationship with the participation and behavior of watershed residents. Also, the regression results and beta values showed that, respectively, the indicators of legal norms, normative beliefs, and participatory norms had the highest priority in the participation and behavior of local communities.

The results showed that about 66% of watershed residents have moderate to low participation and cooperative behavior. The mean ranking results of each of the watershed residents' participation and their behavior to participate in water and soil protection projects show that the watershed residents' care of the projects after its completion, participation in the mortar dam construction project Mortar-cement dam has the greatest effect on their participation and cooperative behavior. Also, the items of participation in the construction of gabion dam project and the desire and intention of watershed residents towards water and soil protection had the least effect on the participation and behavior of watershed residents towards water and soil protection. In general, paying attention to the norms, beliefs, behaviors and attitudes of local communities should be on the agenda of managers and planners to pave the way to protect water and soil resources.

Dust storm is one of the desertification and land gegradation consequences especially in arid and hyper-arid regions of the world. Fine particles released from the Earth's surface can be released several kilometers and subsequently over long distances, sometimes even across continents. These particles play a key role in the Earth system by affecting the radiation balance as well as forest and ocean ecosystems. Weather is often considered as the main factor influencing the occurrence of dust storms. Dust storms have increased in recent years mainly due to continued droughts and global warming. Temperature is an important variable in climatilogy in terms of its direct effect on weather variables such as pressure, wind movement, cloud formation and precipitation. Based on previous studies, the increase in temperature along with the decrease in rainfall and the increase in wind speed provide the conditions for the creation of dust storms. In general, the review of the studies conducted in the field of evaluating dust changes and the effect of temperature parameters on it shows that it is possible to conduct these studies from different perspectives and methods. Therefore, it is necessary to find a comprehensive view on dust and factors affecting it by reviewing and evaluating the results of other studies so that the phenomenon can be controlled and managed. The number of dusty days in Khuzestan province is significant and has increased in recent years. The reason for that is its proximity to the great deserts of the neighboring countries. Therefore, this province is one of the challenging areas of the country in the field of dust management and control. The purpose of this study is to evaluate the trend of dust changes and the effect of temperature on this phenomenon. The results of this study help to better understand the phenomenon of dust in Khuzestan province.

In this research, three data groups were used including the monthly average temperature of 13 meteorological stations in the study area, the monthly average land surface temperature (LST), and the monthly average aerosol optical depth (AOD). First, the trend of dust changes was evaluated using the Mann-Kendall test. Then, the relationship between temperature parameters and dust was investigated using the correlation between the AOD in a buffer of 5 km around the selected stationwith temperature parameters including monthly average temperature and average monthly LST in buffers of 5, 10 and 20 km around the selected station.

The evaluation of the average changes in the buffer of 5 km around the selected stations showed that in the months of February, July, December and April, no increasing trend was observed in any of the stations and even in the month of April, there was a decreasing trend in two stations. The trend of AOD changes was increasing with a probability of more than 90% in the months of August, September and November in seven, March in five, October in four, January in three, May in two and June in one station. The correlation results of temperature parameters and AOD showed that a very strong correlation between average LST and AOD has occurred only in the three months of May, June and July in different buffers. There are the highest number of strong correlations in the months of May to August between temperature parameters and AOD. Also, the highest number of very weak correlations occurred in April, March, November, and December. The highest number of very weak and weak correlations are related to air temperature (85 and 47 numbers, respectively). This shows that LST is more important than temperature in evaluating changes in dust intensity in the study area.

According to the results of this research, it can be said that air temperature has a weak correlation with dust, and most of the strong and very strong correlations occurred with the average LST in different buffers, which shows that LST is more important than temperature in evaluating dust intensity changes in the study area. In general, evaluation and monitoring of dust changes can be effective in identifying new dust sources as well as evaluating wind erosion, dust control, and management activities. Therefore, it can be suggested that an online and up-to-date system based on remote sensing and artificial intelligence be designed and presented to evaluate and monitor dust changes. In this case, the management of the dust phenomenon in Iran will be more targeted and the dust sources can be identified faster. On the other hand, one should pay attention to the factors affecting these changes and evaluate their effect on dust.

Climate change has a significant impact on water resources and the environment, which is reflected in agriculture, society, and economy. The use of General Circulation Models (GCMs) with downscaling models is a method for assessing climate change. Considering the placement of South Khorasan Province and the city of Birjand in the arid region of Iran, population growth, industrial and mining development, and the pursuit of sustainable agriculture, it is essential to assess the effects of climate change on essential meteorological parameters. The objective of this study is to compare the performance of historical models NCEP and ECMWF in downscaling temperature parameters for the Birjand County and investigate the changes in this parameter until 2030 using the top model and the SSP245 scenario with the CanESM5 model.

In this research, to compare the performance of two GCMs, NCEP and ECMWF, in downscaling temperature parameters, daily temperature data from the Birjand synoptic station for the period from 1990 to 2021 were used as the baseline period. Additionally, to evaluate the performance of these two GCMs, the statistical downscaling model SDSM was utilized. To assess the performance of these two models, evaluation criteria such as NS, KGE, RMSE, and BR2 were employed.

To investigate and compare the performance of two GCMs, NCEP and ECMWF, daily average temperature data from the Birjand synoptic station were used from the January 1990 to the September 2021. The data from 1990 to the January 2008 were considered for calibration, and data from the January 2008 to the September 2015 were used for validation. Both NCEP and ECMWF models had 26 parameters, and for downscaling, the parameters with the highest correlation with observed temperature were selected among these 26 parameters using the R software and the HydroGof package. Additionally, evaluation criteria such as NS, RMSE, KGE, and BR2 were used to assess the models' performance in calibration and validation sections. The closeness of variance and mean values of time series generated by the NCEP and ECMWF models to the variance and mean values of observed time series in the entire simulation period was examined using F and T tests. The results of the calibration section showed that the two models, NCEP and ECMWF, exhibited similar performance since the values of evaluation criteria NS, RMSE, KGE, and BR2 for the ECMWF model were calculated as 0.69, 4.86, 0.85, and 0.7, respectively, and for the NCEP model, they were 0.70, 4.79, 0.85, and 0.7, respectively. Since box plots, mean values, and standard deviations have a high capability in deciding the degree of dispersion and similarity between two time series, box plots, mean values, and standard deviations of the generated time series and observed time series in the calibration and validation periods were used to assess the similarity and closeness of the time series. The results of the evaluation criteria in the validation section showed that the ECMWF model outperformed the NCEP model, with values of evaluation criteria NS, RMSE, KGE, and BR2 for the ECMWF model being calculated as 0.69, 4.9, 0.85, and 0.73, respectively, and for the NCEP model, 0.67, 5.3, 0.83, and 0.7, respectively. Overall, the results indicated that the ECMWF model had a better performance and was selected as the superior model. Therefore, to simulate and predict the average temperature parameter, the parameters mslp, P500, P5-f, P5-u, P850, and P8-u from the ECMWF model were used. Consequently, it is predicted that the average temperature will increase by approximately 3 degrees Celsius compared to the statistical baseline period in the next 8 years.

The results indicate that based on the evaluation criteria, the ECMWF model performs relatively better in estimating the average temperature of Birjand County compared to the NCEP model. Moreover, the analysis of box plots, mean values, and standard deviations of the generated time series in the calibration and validation sections showed that both models produced similar patterns of dispersion, minimum, maximum, and mean values compared to the observed time series. However, the ECMWF model exhibited relatively better performance in terms of mean and variance values of the generated data on a monthly basis in the calibration and validation periods. As a result, the ECMWF model was selected as the superior model for simulating and predicting the average temperature of Birjand County for the years 2022 to 2030 under the SSP245 emission scenario using the CanESM5 model. The predicted results indicate that the average temperature of Birjand County is expected to increase by approximately 3 degrees Celsius compared to the statistical baseline period.

The growing global population and increasing demands have significantly intensified the pressure on natural resources and created inherent instability in watershed ecosystems and the complex ecological processes essential for habitat preservation, biodiversity conservation, erosion mitigation, soil formation, water retention, environmental stability, and cultural fulfillment have encountered disruptions. The inter-connected adaptability challenges within human-natural systems, intensified by climate change, bring more uncertainty that complicates the planning and management of ecosystem services in the watersheds. This uncertainty often results in flawed decision-making in water resources utilization and environmental management, contributing to instability and a shift toward critical thresholds in watersheds. This study adopts a systemic approach to analyze the Karoun Basin as a dynamic human-nature system, exploring five systemic analysis patterns and their impacts on water resource management paradigm.

The research progresses through three crucial steps. Firstly, the current status of the Karoun Basin is outlined based on extensive literature studies, characterizing the water system as a complex, adaptive entity. Secondly, leveraging a diverse range of research literature, five recognized structures in dynamic system analysis are explored. These structures offer a detailed understanding of the interconnectedness of human-nature systems, providing insights into the impact of human behavior on water resources management in the Karoun Basin. In the final step, using a systemic thinking approach, the study explores the occurrence of extreme events. This approach enhances the understanding of how extreme events interact with human activities, influencing the sustainability of the Karoun Basin.

The outcomes highlight the inherent risk of a linear approach to water resource management in the Karoun Basin, which is because of the lack of systemic thinking. This approach disrupts various relationships within the water system, leading to instability and worsening extreme events such as floods, droughts, and water disputes. The systemic investigation reveals recurrent behaviors that align with recognized structures in dynamic systems analysis, referred to as ancient patterns. Understanding and addressing these patterns are crucial for achieving sustainability and ensuring the continuous provision of ecosystem services.

Depending solely on short-term solutions, without considering long-term consequences in water resource management worsens water scarcity issues and intensifies social conflicts within watershed units. Solutions for Karoun Basin can be categorized into mitigating (hard) and adaptive (soft) scenarios. Mitigating measures address immediate needs, including advanced water storage and distribution infrastructure, while adaptive solutions incorporating policy measures are crucial for aligning the managed system with fluctuating water availability levels. A comprehensive resolution requires the simultaneous implementation of both strategies, recognizing the interconnected nature of human-nature systems and embracing sustainability principles.

Eskandari sub-watershed is one of the most important water supply sources for agriculture, drinking and industry in Isfahan region and province. Therefore, better understanding of the problems within this watershed is crucial for planning and proper management. Moreover, a concerted effort to engage all stakeholders in the integrated management of this watershed is necessary. This research aims to investigate the reasons for the increase of runoff in the years 2011, 2021, and 2031, providing management solutions with the active participation of stakeholders.

First, the height of the runoff was estimated using the curve number method. In this regard, Landsat 5 and 8 satellite images from 2011 and 2021 were used to prepare a land-use map of the Eskandari sub-watershed. Additionally, the prediction of land-use changes in the future (2031) was done using the Markov model. To prepare the curve number map, the combination of the land-use map and hydrological groups was used, and then the runoff height was estimated in the studied years. Following this, through collaborative workshops, stakeholders were asked to create a problems and objectives tree based on the main reasons for the runoff progress in the watershed, consulting with each other. Subsequently, based on the objective tree, the initial list of proposed solutions for the Eskandari sub-watershed was presented. The proposed solutions were then refined, classified, and prioritized by experts. Continuing with the goals of the current research, the most important indicators affecting the current situation of the Eskandari sub-watershed were selected based on the opinions of experts and stakeholders. To model, the multi-criteria decision-making method was used to select solutions and prioritize them. Therefore, initially, the researcher's questionnaire was distributed among stakeholders for scoring the selected solutions according to the assessment criteria. Finally, the results obtained from experts' scoring were prioritized using the TOPSIS method.

The results reveal a significant reduction in natural lands in the region. Consequently, by 2031, rangelands with good and mediocre cover have been completely destroyed, while those with poor cover, irrigation, and rainfed agriculture dominate the region. Based on soil science information, 57.18% of the area is related to hydrological group B with a medium runoff production capacity. Hydrological groups C and D, with percentages of 24.98 and 17.82, respectively, are the next priorities. Following this, by combining the hydrological group map of the watershed with the land-use map in GIS environment, the CN map with curve numbers ranging from 61 to 96 was obtained. Finally, the average infiltration in 2011, 2021, and 2031 was 79.15, 62.82, and 55.12 mm, respectively, while the average runoff in those years was 10.99, 13.15, and 13.38 mm, respectively. According to the results, the losses decrease over time, while the runoff increases. Residential lands and rocky outcrops have the highest amount of runoff production, i.e. 34.38 mm, whereas rangeland with good cover (0.33) has the lowest amount of runoff. In subsequent collaborative workshops, based on the opinions and consensus of stakeholders and experts, improper agriculture was identified as one of the main reasons for increase of runoff in the studied area. Due to a lack of water, insufficient income, and a lack of laws and supervision in the region, watershed farmers and residents are changing land use and cultivating low-yielding lands in an unprincipled manner. Also, in line with the research goals, 11 management solutions and 12 effective indicators (economic, social, and environmental sectors) were identified for the current situation of the watershed. The prioritization results based on the TOPSIS method showed that the solution of creating cover farming to increase surface coverage has been assigned the highest priority.

In this research, efforts have been made to address and mitigate the runoff in the study area. Management solutions have been presented based on the preferences and participation of stakeholders. Therefore, to prevent further runoff in the region, it is suggested to establish institutions tailored to the watershed's situation, considering patterns of cultivation and conservation agriculture, and integrating the cooperation of subordinate institutions and organizations.

The study of erosion and sedimentation is a crucial aspect and an integral part of watershed studies in a basin. The methods employed to prevent erosion and sedimentation play a significant role in basin management planning. However, due to the lack of accurate statistics on erosion and sediment amounts, it becomes necessary to utilize estimation models for assessing erosion and sedimentation. These models are often region-specific and may have a wide range of uncertainty in different areas. One notable benefit of modeling, regardless of its type, is its ability to analyze natural processes within the basin. On the other hand, understanding erosion and sedimentation processes in a region can be an effective step in managing, planning, and prioritizing available resources. In this research, the aim was to determine the sensitivity of the MPSIAC model to the relationships among its parameters. Additionally, the goal was to assess the model's sensitivity to changes in these parameters and their impact on sedimentation. By identifying the influential ground and atmospheric parameters, it becomes possible to prioritize their effect on water sedimentation in the region.

Through the sensitivity analysis of the model, it is possible to identify the flexibility of the model to the changes of its various parameters. It is also possible to determine the relationships between model variables and prioritize the parameters affecting the model output. Sensitivity analysis can be used in the calibration stage, in such a way that results are accurate, and time and cost are saved. In this study, to analyze the sensitivity of the MPSIAC model, first, the nine parameters of the model were examined. Then, according to the arrangement of different parameters in the structure of this model, the parameters were numbered from X1 to X9. Then, the score range of each parameter was entered in its calculation table according to the modified model of PSIAC. In this step, the average of each parameter was calculated according to its upper and lower limits. To achieve this, the nine parameters of the model were standardized, and the sedimentation rate was estimated by varying each parameter within its lower and upper limits while keeping the other parameter(s) fixed at their averages. With each change, the sediment discharge was calculated.

In the analysis of the results, the slope of the curves of the standardized parameters relative to the dependent variable (specific sediment) is considered. So that, any part of the curve that has more slope changes means that the model is more sensitive to minor changes in that parameter in that interval. In this study, the results of this sensitivity analysis reveal that the slope factor and runoff volume have a considerable influence on sediment yield. For slopes up to approximately 15%, the slope parameter has a relatively smaller impact compared to other parameters. However, as the slope value increases, its effect becomes more pronounced, indicating that high slopes (greater than 15%) have the greatest impact on sedimentation. The runoff factor exhibits a sudden increase in sensitivity at higher flow rates.

In examining the effect of different parameters on the model performance, the parameters that had the largest slope of changes can be considered as the most effective parameters in sedimentation of the basin. In other words, the model demonstrates high sensitivity to slight changes in specific peak discharge values above 20 m³/s/km2. Therefore, implementing integrated (biomechanical) management measures to control slope steepness and reduce runoff volume can be an effective strategy for mitigating sedimentation. Therefore, based on the results, the role of land factors is very important, such as slope and then runoff, in the erodibility and sediment production in basins. Of course, it should be noted that climatic parameters directly and indirectly affect the amount of peak flood discharge and should not be neglected for their importance and influence in flooding and subsequently the erodibility of the watershed.