seid omid aleyasin; bahman shamsesfandabad; Hamid Toranjzar; abas ahmadi; Shahro Mokhtari
Abstract
Abstract: Wetlands are one of the most productive ecosystems in the world. They provide a unique and rich habitat for creature .they also perform a wide range of economic and service functions such as water conservation, runoff regulation, water quality treatment and recreational services. The aim of ...
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Abstract: Wetlands are one of the most productive ecosystems in the world. They provide a unique and rich habitat for creature .they also perform a wide range of economic and service functions such as water conservation, runoff regulation, water quality treatment and recreational services. The aim of this study was to evaluate the ecosystem health of Meyghan Wetland of Arak based on different methods. To evaluate the Meyghan Wetland of Arak and also to evaluate the status of benthic organisms and other parameters, sampling of sediments of the wetland floor was performed. Sampling was performed at 10 points of the wetland and at 5 replications at each point. Several indicators were used to assess the health of Meyghan Wetland. Which included a biotic-index (BI) based on the work of Borja et al. (2000). In addition to the above, the main framework includes bio-indicators, heavy metal pollution index and water quality index, which have been considered in this study. The ecosystem health of Meyghan Wetland was evaluated based on the mentioned indicators and the map of ecosystem health of Meyghan Wetland was prepared. The results of this study showed that except for the nickel, zinc and lead as well as pH, for other elements (EC, Na, Cl, Mg, Ca, HCO3, SO4 and TDS), the lowest and highest values belong respectively To stations 3 and 6. The high amount of these elements in station 6 can be due to the activity of sodium sulfate factory in the northern part of the wetland, which causes changes in the wetland ecosystem by removing sediments from the wetland floor. In the case of copper, zinc and lead, the lowest concentration is seen in the northwestern part of the wetland and the highest concentration is seen in the western and southeastern parts of the wetland.
mohammad taghi heydari; Hosseinali Bahrami; , alireza aliyari
Abstract
Soil moisture is one of the fundamental parameters of the environment that is directly influenced by plant life, animal and activity of micro-organisms and plays a major role in energy exchanges between air and soil. Determination of the exact amount of soil moisture content in agricultural, hydrology ...
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Soil moisture is one of the fundamental parameters of the environment that is directly influenced by plant life, animal and activity of micro-organisms and plays a major role in energy exchanges between air and soil. Determination of the exact amount of soil moisture content in agricultural, hydrology and geological sciences is very important. Therefore, the use of a method that can achieve soil moisture in normal and non-corrosion conditions with high speed and accuracy is very important and fundamental. The Ground Penetrating Radar (GPR) is a non-destructive method for the subsurface investigation that is evolving and seems to be able to greatly help agriculture to identify soil and protect culture systems. Different studies have been done in the field of soil moisture determination using GPR, but in Iran, there are limited studies on the ability of this method to estimate spatial changes of soil moisture content, therefore, this research has been done with these goals. The results indicate that in the study area, the distribution of humidity at each stage of harvest shows limited changes if the time changes of humidity in the time interval between winter and spring are about 10-15% of the difference. Also, the mean square of GPR method error compared with TDR 13.2 method is also compared to the GPR and weighted 81.3 method and the correlation coefficient in these two comparisons is equal to 0.87 and 0.95, which indicates the high accuracy of the GPR method for estimating soil moisture.
mehri raoofi; Mahmoud Habibnejad Roshan; Kaka Shahedi; Fatemeh Kardel
Abstract
Rivers are the main arteries of watersheds that play an important role in providing water for agriculture, drinking and industry. On the other hand, the reduction of river water quality has been one of the biggest human concerns in the last century. In order to evaluate the quality of running water, ...
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Rivers are the main arteries of watersheds that play an important role in providing water for agriculture, drinking and industry. On the other hand, the reduction of river water quality has been one of the biggest human concerns in the last century. In order to evaluate the quality of running water, biological indicators and the study of benthic invertebrates can be used. The aim of this study was to investigate the water quality of the main rivers of Babolrood watershed using the Hilsenhof Biological Index (HFBI). For this purpose, sampling of benthic invertebrates in 5 main river stations was performed using a net frame (sorber) with a cover area of 40 cm2 and transferred to the laboratory for identification. Then, using Pennak (1953) and Mellenby (1963) identification keys, the samples were identified by family and sex and counted and weighed. Also, at the same time as sampling of benthic organisms to study the physicochemical properties of water, samples were taken from river water. Pearson correlation coefficient was used to investigate the relationship between biological samples and physicochemical properties of water. The results showed that Babolk station with the lowest FBI and Babolrood-Babol station with the highest FBI were in the category of non-organic pollution and some organic pollution, respectively. The results of correlation of biological samples with physicochemical parameters in most cases were not significant at 95% confidence level. The highest correlation coefficient between Oligochaeta species was with Diversity biodiversity.Keywords: Benthic invertebrates, water quality, HFBI, Babolrood watershed, Mazandaran province
mohammad Rostami
Abstract
To evaluate the scour depth around cylindrical piles of coastal protection structures under wave impact pressure caused by wave breaking, an experimental study was designed. The study aimed to analyze how variations in wave characteristics, including wave height and period, influence scour depth. It ...
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To evaluate the scour depth around cylindrical piles of coastal protection structures under wave impact pressure caused by wave breaking, an experimental study was designed. The study aimed to analyze how variations in wave characteristics, including wave height and period, influence scour depth. It is important to note that this research focuses on breaking waves that directly impact the structure.In this study, a two-dimensional wave channel at the Coastal Engineering Laboratory of the Soil Conservation and Watershed Management Research Institute was used. To create shallow water conditions and ensure wave breaking at the pile location, as well as to assess the resulting scour depth, a sloped surface and a sediment reservoir were constructed in the middle section of the main channel. The sediment reservoir, with a depth of 0.35 meters, was installed upstream of the metal sloped surface and filled with sand sediments. A polycarbonate cylindrical pile was positioned at the center of the sediment reservoir.The wave channel was filled with water to depths ranging from 0.4 to 0.5 meters, and waves of varying heights and periods were generated using a wave paddle system. Through trial and error, the exact wave breaking location and the pile’s position relative to it were identified. A total of 34 experiments were conducted under initial water depths ranging from 0.4 to 0.5 meters. Wave heights varied between 0.05 to 0.14 meters, and wave periods ranged from 2 to 7 seconds. After each experiment, scour depth at the pile location was captured and measured using imaging techniques.The findings of this study revealed that wave breaking resulted in a 2.37-fold increase in scour depth and erosion compared to the passage of a regular wave near a cylindrical pile structure.Therefore, marine structure designers must carefully consider this issue.
Rouhangiz Akhtari; Hamidreza Hajipoor; Mojtaba Saneie; Mohammadreza Gharibreza
Abstract
This study experimentally evaluates the performance of individual check dams in mitigating flood peaks using a 1:10 scale physical model of Sijan stream, testing 90 scenarios under controlled laboratory conditions. The research systematically examines how stream characteristics (number of check dams ...
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This study experimentally evaluates the performance of individual check dams in mitigating flood peaks using a 1:10 scale physical model of Sijan stream, testing 90 scenarios under controlled laboratory conditions. The research systematically examines how stream characteristics (number of check dams and their sediment conditions) and inflow parameters (peak discharge and hydrograph time base) influence flood control effectiveness. Results demonstrate that check dams reduce peak discharge by 5-16% and increase time lag to peak by 17-21%, with performance highly dependent on flood magnitude and duration. For floods with return periods increasing from 2 to 10 years, the peak reduction efficiency decreases from 16% to 5%, revealing structural limitations against higher energy flows. The hydrograph time base emerges as a critical factor - when exceeding the watershed's time of concentration, peak mitigation drops from 17% to 5% and time lag decreases from 35% to 8%, indicating reduced effectiveness for prolonged flood events. These trends are attributed to flow dynamics: larger floods overwhelm structural resistance, while extended durations lead to control saturation and steady flow dominance. The study develops three robust empirical relationships (R² = 0.81-0.92) through dimensional analysis to quantify check dam impacts on hydrograph modification, providing practical tools for watershed management. However, the derived equations require site-specific calibration for application beyond the Sijan stream due to their dependence on local channel geometry and roughness characteristics. These findings offer valuable insights for designing check dam systems, highlighting their conditional effectiveness and the importance of considering both flood magnitude and duration in watershed management strategies. The research contributes to improved flood control planning by quantifying performance limitations under varying hydrological conditions.
Mahmoudreza Tabatabaei; Mohammadreza Gharib Reza
Abstract
This study examines the accurate estimation of suspended sediment in the Atrak River, particularly at the Hootan station. Suspended sediment in rivers, especially in semi-arid regions, poses significant challenges for water resource management and sediment control in dam reservoirs. In this research, ...
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This study examines the accurate estimation of suspended sediment in the Atrak River, particularly at the Hootan station. Suspended sediment in rivers, especially in semi-arid regions, poses significant challenges for water resource management and sediment control in dam reservoirs. In this research, a combination of classical and intelligent methods was used to estimate suspended sediment, including sediment rating curves, neural networks, and deep learning models. Key variables influencing sediment were identified using a random forest algorithm, and the data was divided into homogeneous groups. The ensemble learning model, XGBoost, was selected as the best model, demonstrating high accuracy in predictions. Results indicate that XGBoost outperformed other models with the lowest error and highest performance index. This model effectively manages highly skewed data and identifies complex nonlinear relationships. Additionally, the combined approach used in this study improved predictions compared to traditional methods. However, data quality and hydrological changes significantly impact model performance. This research highlights the importance of advanced machine learning techniques in analyzing hydrological data and emphasizes the need for a link between data science and water resource management. The findings of this study can serve as a reference for policymakers and water resource managers in enhancing sediment management and water quality in rivers.
Asghar heidari
Abstract
In this study,the effect of application super absorbent material on growth of rain-fed trees in managed rainwater harvesting systems was investigated and application or non-application of superabsorbent as main treatment, three management treatments including: no change at the level of system,Trench ...
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In this study,the effect of application super absorbent material on growth of rain-fed trees in managed rainwater harvesting systems was investigated and application or non-application of superabsorbent as main treatment, three management treatments including: no change at the level of system,Trench collection and vegetation cover of the system level and Semi-insulated treatment as sub-treatments and Was examined with randomized complete block design two fruit tree including almond and apricot as sub-treatments in a split plot design. During the design, tree growth indices including changes in diameter, height and canopy of seedlings were measured in different treatments of rain water harvesting.Results show that the systematic surface treatment of rain water harvesting systems with vegetation had the lowest diameter and height growth in almond and apricot seedlings and the insulated treatment had the highest diameter and height growth. This is indicative of the effect of creating a system of rain water harvesting systems with different cover levels to produce different runoff amounts and as a result the difference in diameter and height growth of the seedlings planted. Significant level differences between treatments and blocks in the diameter growth rate of almond and apricot seedlings in the year in experimental treatments with and without super absorbent at less than 1% error indicates that the operation performed in each of these treatments.But result of the variance analysis showed that the presence or absence of superabsorbent hadn't significant effect on their growth. So whether significant in plant growth in the use of superabsorbent materials is not a general and permanent state and depends on the climatic conditions of the area, the type of soil and its texture, the type of plant and even the topographical and slope conditions of the planting site. Therefore, any plants or seedlings should be evaluated and evaluated in the area.
Ali Salajegheh; Vahid Payravand; Mohammad Reza Sayyadi
Abstract
Underground dams, as a method for reducing water loss and contamination, offer significant potential for improving groundwater management. However, their implementation in Iran is accompanied by technical, social, economic, and institutional challenges. This study aims to develop a management framework ...
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Underground dams, as a method for reducing water loss and contamination, offer significant potential for improving groundwater management. However, their implementation in Iran is accompanied by technical, social, economic, and institutional challenges. This study aims to develop a management framework for underground dam implementation using a grounded theory approach. This qualitative research was conducted following Strauss and Corbin’s grounded theory methodology. The participants included 14 experts in watershed management and underground dams with at least 15 years of experience, selected through purposive and snowball sampling. Data analysis was conducted in three stages of open, axial, and selective coding; a total of 201 open codes were extracted and organized into 49 axial codes and 22 main categories. Validity and reliability were ensured through expert evaluation and agreement among coders.Data analysis led to the development of a paradigmatic model for the management of underground dam implementation. Causal conditions included the inefficiency of surface dams and livelihoods were introduced as the motivation for paying attention to this technology. Contextual conditions Intervening conditions such as policies, regulations, operational barriers, social participation, and economic justification influenced the process. Key strategies included comprehensive planning, technological improvement, stakeholder engagement, socio-economic planning, and capacity building. Expected outcomes were enhanced water resources sustainability, developed economic efficiency and Sustainable agriculture, and achieves ecological balance. Underground dams in Iran can be considered as a complementary option depending on local conditions, and their success requires simultaneous attention to technical, social, economic, and institutional dimensions. The presented model provides a comprehensive framework for planning and managing underground dams projects, and by integrating effective factors and implementing key strategies, it can help reduce risk and create sustainable projects in the long term.
Ahmadreza Karimipour; saleh yousefi; sara mardanian
Abstract
Land subsidence, as a serious natural hazard influenced by the overexploitation of groundwater resources and geological factors, causes extensive damage to infrastructure and agricultural lands. This study was conducted with the aim of zoning subsidence risk in Chaharmahal and Bakhtiari province using ...
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Land subsidence, as a serious natural hazard influenced by the overexploitation of groundwater resources and geological factors, causes extensive damage to infrastructure and agricultural lands. This study was conducted with the aim of zoning subsidence risk in Chaharmahal and Bakhtiari province using the powerful AdaBoost machine learning model. In the first step, from among 30 initial effective factors including topographic, hydrological, geological, environmental, and climatic parameters, and after performing correlation analysis and removing collinear variables, 23 final factors were selected for modeling. The AdaBoost model was trained using 2352 training samples (including subsidence and non-subsidence points) and was validated on an independent test set consisting of 772 samples.The evaluation of the model's performance using valid indicators showed its highly desirable accuracy and efficiency, such that the values for the Area Under the Curve (AUC), Precision, Recall, and Kappa coefficient were obtained as 0.974, 0.936, 0.981, and 0.855, respectively. Based on the model output, the final land subsidence risk zoning map was prepared in five classes: very low, low, medium, high, and very high. The results indicated that the Borujen and Shahrekord plains are at the highest risk of subsidence, and parts of the Lordegan plain also fall into the very high-risk category. The analysis of variable importance using the SHAP method revealed that the three factors of land slope angle, surface sand percentage, and groundwater level changes have had the greatest impact on the occurrence of land subsidence in the region, in that order. Specifically, an inverse relationship was observed between land slope and subsidence intensity. Furthermore, a drop in groundwater level plays a direct role, while an increase in surface sand percentage plays a mitigating role in the occurrence of this phenomenon.
Omid Asadi Nalivan; Gholamreza Khosravi; Ehsan Alvandi
Abstract
The Watershed Sustainability Index (WSI) is one of the valid indicators that quantifies the sustainability status of a watershed. The Atrak River watershed is located in Golestan Province and has an area of 819,000 hectares. The Watershed Sustainability Index is one of the few indicators designed ...
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The Watershed Sustainability Index (WSI) is one of the valid indicators that quantifies the sustainability status of a watershed. The Atrak River watershed is located in Golestan Province and has an area of 819,000 hectares. The Watershed Sustainability Index is one of the few indicators designed specifically for watersheds, developing the UNESCO-HELP model and using the PSR (Pressure-Status-Response) causal model. It evaluates the sustainability of the watershed in question numerically and using a formula in the form of four sub-indices of hydrology (qualitative and quantitative), environment, life (livelihood conditions and human development), and policy. In this method, by considering the information and data available for examining each of the sub-indices, the values of the parameters are determined in three states of pressure, status, and response and are converted into quantitative form in a scoring range from zero to one and in five categories (0, 0.25, 0.5, 0.75, 1). The final WSI value is calculated through the arithmetic mean of the sub-indices at three levels: low, medium, and high. The final results of the WSI method showed that all sub-basins have a poor sustainability status in all four main indicators. Considering the average score (0.448), the Atrak watershed is in the low category in terms of sustainability. Considering the results obtained and the low sustainability level of the Atrak River watershed, it is necessary to take immediate and planned measures to improve the sustainability status. The most important and applicable management suggestions in the basin include the following: Comprehensive water resources management, improving the quality of water resources, including controlling and reducing pollutant inputs, protecting and restoring natural vegetation, and strengthening environmental governance and policymaking.
Mehri Dinarvand; saba peyrov; seyed hossein Arami; behzad tajari; kohzad heidari
Abstract
Iran is located in the arid and semi-arid belt of the world and is very far from moisture sources. Arid and desert areas, due to a lack of moisture, high temperatures, strong winds, soil erosion, and land degradation caused by human activity, have created tough conditions for plant growth and development, ...
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Iran is located in the arid and semi-arid belt of the world and is very far from moisture sources. Arid and desert areas, due to a lack of moisture, high temperatures, strong winds, soil erosion, and land degradation caused by human activity, have created tough conditions for plant growth and development, such that only a relatively limited number of plant species can survive. Native plants of such areas are considered highly valuable species due to their ability to adapt to harsh environmental conditions and play a crucial role in the region's climate, soil formation, and hydrology; therefore, their identification is of great importance. With the aim of monitoring and recording spatial data statistics of meteorological, hydrometric, erosion and sedimentation, vegetation cover, soil and groundwater climatic parameters, the Shush representative basin station was established in 2007 by the General Directorate of Natural Resources and Watershed Management of Khuzestan Province. In this area, in addition to the Moorlands, shallow depressions and old gullies are observed in this basin, some of which have been stabilized due to enclosure and reduction of livestock pressure. These stabilized depressions themselves act as natural micro-reservoirs and have provided suitable conditions for the establishment of permanent species by increasing infiltration, reducing surface runoff, and trapping plant seeds. In this study, the floristic composition, richness, and species diversity were compared in plots located in stabilized micro-watersheds (treatment) and hills (control).Materials and methods:In this study, vegetation cover analysis was conducted in the Shoosh representative basin area using biodiversity indices. During the appropriate growing season (early February to late March), during field visits, a list of plant species in the area was taken, and typification was performed based on the presence of shrub and perennial species.
Mohammad Rostami Khalaj; Hamze Noor; Ali Bagheryian Kalat
Abstract
Drought propagation refers to the transmission of moisture deficits from meteorological to hydrological drought, representing a central issue in water resource management in arid and semi-arid climates. This study was conducted to analyze the spatial propagation of drought and examine the role of environmental ...
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Drought propagation refers to the transmission of moisture deficits from meteorological to hydrological drought, representing a central issue in water resource management in arid and semi-arid climates. This study was conducted to analyze the spatial propagation of drought and examine the role of environmental characteristics in Khorasan Province. Meteorological and hydrological droughts were identified using the Standardized Precipitation Index and Standardized Streamflow Index , Drought events were extracted using a threshold of ≤ -1, and paired events were determined. For each event, the severity and intensity of meteorological and hydrological droughts were calculated, followed by the derivation of propagation ratios for severity and intensity and their normalized versions. A set of physiographic and climatic variables including slope, NDVI, precipitation seasonality index , snow fraction , aridity index , and available water capacity were extracted as basin-wide averages and subjected to correlation analysis.Spatial analyses revealed that the mean severity of meteorological drought ranged from 0.23 to 2.17, with an approximate average of 2.1, whereas hydrological drought severity ranged from 0.14 to 1.16, with a mean of 0.65. The coefficient of variation for hydrological drought severity was approximately 63%, compared to 37.7% for meteorological drought severity, indicating greater spatial variability in hydrological drought. At the basin scale, 54% of basins exhibited a decrease in severity propagation, and 67% showed a decrease in intensity propagation, with mean severity and intensity propagation ratios of -0.03 and -0.1, respectively. This pattern reflects a general attenuation of drought effects as they transition into hydrological systems. Significant negative correlations were observed between meteorological drought characteristics and propagation ratios for severity and intensity (-0.48 and -0.67, respectively), indicating that meteorological events with higher severity and intensity tend to experience greater attenuation during propagation. In other words, high-intensity atmospheric drought does not always translate into corresponding hydrological drought severity.
Negar Arjmand; علیرضا Sepahvand; Omid Rahmati
Abstract
This research was conducted with the aim of mapping the susceptibility to gully erosion using artificial intelligence models in the Alashtar watershed, Lorestan Province. The study area, covering 797.64 km2, is part of the Karkheh watershed. In this study, 12 effective factors were used as input data, ...
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This research was conducted with the aim of mapping the susceptibility to gully erosion using artificial intelligence models in the Alashtar watershed, Lorestan Province. The study area, covering 797.64 km2, is part of the Karkheh watershed. In this study, 12 effective factors were used as input data, including slope, aspect, precipitation, distance from road, distance from river, distance from fault, soil type, land use, geological formation, Topographic Wetness Index (TWI), Topographic Position Index (TPI), and Normalized Difference Vegetation Index (NDVI). Out of a total of 151 observation points (89 gully points and 62 non-gully points), 70% were used for training stage and 30% for testing stage. The performance of three AI models—Multilayer Perceptron Artificial Neural Network (MLP), Maximum Entropy (MaxEnt), and Flexible Discriminant Analysis (FDA)—was evaluated using the ROC curve and the Area Under the Curve (AUC) index. The results showed that the MLP model, with AUC values of 0.98 in the training phase and 0.92 in the validation phase, had the best performance in predicting gully erosion susceptibility. This was followed by the FDA (AUC = 0.87) and MaxEnt (AUC = 0.5) models, respectively. Analysis of the influencing factors revealed that most gullies were located in precipitation classes of 600-700 mm, distances greater than 300 meters from faults, roads, and rivers, slope classes of 0-5% and 5-15%, northern aspects, dry farming land use, and geological formations of old alluvium and marls. Furthermore, a direct relationship was observed between the TWI index and gully occurrence, while an inverse relationship was found for the NDVI index. Finally, the gully erosion map was prepared using the MLP model. Result shown that artificial neural network, is an effective tool for identifying areas susceptible to gully erosion and helps to planning and management to control this phenomenon in similar regions.
Seyed Morteza Seydian; Hossein Emami
Abstract
Any modeling and decision-making process in watershed management fundamentally depends on accurate discharge data at the basin outlet. However, direct measurement of discharge is both costly and time-consuming. Therefore, at hydrometric stations, water stage is routinely recorded, and discharge is estimated ...
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Any modeling and decision-making process in watershed management fundamentally depends on accurate discharge data at the basin outlet. However, direct measurement of discharge is both costly and time-consuming. Therefore, at hydrometric stations, water stage is routinely recorded, and discharge is estimated using the rating-curve equation corresponding to the observed stage. Nevertheless, several sources of uncertainty, including errors in measuring flow velocity, cross-sectional area, and stage height, as well as model limitations in estimating extreme flows and temporal variations in channel morphology caused by erosion, sediment deposition, and vegetation growth, result in inaccuracies in rating-curve-based discharge estimations. Such uncertainties propagate through hydrological model outputs and management decisions, potentially leading to considerable economic and environmental losses. Consequently, it is essential to quantify the uncertainty bounds of rating-curve-derived discharge estimates in order to mitigate risks associated with measurement and estimation errors. To date, both classical statistical and Bayesian approaches have been employed for uncertainty estimation in rating curves. The Bayesian framework, in particular, offers significant advantages: in addition to incorporating observational data through the likelihood function, it allows prior hydraulic knowledge of the station to be embedded in the model through prior distributions. With recent advances in computational power and the widespread application of Markov Chain Monte Carlo (MCMC) sampling techniques, Bayesian methods have become a powerful and flexible tool for rating-curve uncertainty estimation, and various model structures have been introduced in recent years. Accordingly, the present study estimates rating-curve uncertainty using a Bayesian approach for three hydrometric stations located in Golestan Province.
Ramtin Tavoosi Rad; Mohamad ansarighojghar; Arash Malekian
Abstract
Accurate runoff prediction plays a crucial role in water resource management, flood control, and climate change adaptation planning. Given the nonlinear, complex, and multifactorial nature of hydrological processes, the use of data-driven methods and machine learning algorithms has become an efficient ...
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Accurate runoff prediction plays a crucial role in water resource management, flood control, and climate change adaptation planning. Given the nonlinear, complex, and multifactorial nature of hydrological processes, the use of data-driven methods and machine learning algorithms has become an efficient approach for runoff analysis and modeling in recent years. Two individual models, XGBoost, CatBoost, and a hybrid model Boost(Cat-XG) were evaluated to predict runoff in the Karaj watershed. The models were measured with 4 evaluation criteria NS, R, RMSE and MAE. The prediction results showed that the hybrid model (Cat-XG)Boost with a significant difference provides the best performance in predicting monthly runoff of the Karaj watershed compared to the two individual models evaluated. This model recorded NS above 0.957 and correlation above 0.939 in all stations studied. In addition, it recorded significantly fewer errors than the other two models. While the individual models XGBoost and CatBoost, especially in stations with more extensive data, faced increased errors. The two individual models studied provided average performance in predicting values related to extreme climate events, but by combining the two individual models and introducing the hybrid model Boost(Cat-XG), the defects in the individual models were covered and also by eliminating existing errors, much more accurate predictions were recorded.
Bagher Ghermez-cheshme
Abstract
Knowledge of temporal variation of base flow and its change trends in arid and semi-arid regions such as Iran is essential for developing basin water resources management plans. In this study, the Barun-chay River basin was selected with daily stream flow discharge for the period of 1976-1997. Using ...
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Knowledge of temporal variation of base flow and its change trends in arid and semi-arid regions such as Iran is essential for developing basin water resources management plans. In this study, the Barun-chay River basin was selected with daily stream flow discharge for the period of 1976-1997. Using a topographic map with a scale of 1:50,000, the location of the station and the area under study were determined, and the initial parameters of the basin were extracted. Then, the base flow index (BFI) was extracted using the time series of daily stream flow data and the one-parameter Recursive digital filter method. Monthly, seasonal, and annual time series of BFI were prepared, and trend analysis was conducted before and after the dam was constructed upstream of the hydrometric station using the Mann-Kendall method. The results showed that the average long-term annual BFI was 0.552. On a seasonal scale, the highest BFI was related to winter and summer, and the minimum was related to spring. The maximum long-term monthly BFI was related to January at 0.651 and the minimum was related to May at 0.470. The distribution of BFI data indicates that 50 percent of BFI in spring was between 0.47 and 0.53, in summer between 0.55 and 0.62, in autumn between 0.49 and 0.55, in winter between 0.52 and 0.64, and annually between 0.52 and 0.57. The trend of BFI in all time steps of the month, season, and year, except for June and October, was negative. The long-term average BFI before the construction of the dam, 1976 to 1995, was 0.542, and after the dam construction, 1995 to 1997, it was 0.562. It is noteworthy that the impact of human interventions resulting from the construction of the dam on the long-term annual BFI was 0.02.
Amin Salehpour Jam; Noredin Rostami; Shokoufeh Abdali
Abstract
In this study, aimed at assessing managerial-institutional resilience across different sub-watersheds of the Sang Sefid watershed, the indicators for each of the aforementioned components were first identified based on a review of the literature, library studies, interviews with experts, and field observations. ...
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In this study, aimed at assessing managerial-institutional resilience across different sub-watersheds of the Sang Sefid watershed, the indicators for each of the aforementioned components were first identified based on a review of the literature, library studies, interviews with experts, and field observations. In this research, using a multi-response coding method, the questionnaire variables were qualitative ordinal variables, consistent with the Likert scale (Very Low = 1, Low = 2, Moderate = 3, High = 4, and Very High = 5). Following the assessment of the questionnaire's validity and reliability, a survey was conducted among the watershed residents. In this regard, the validity of the measurement instrument was confirmed by a panel of experts, and the sample size was calculated using Cochran's formula. It should be noted that 14 expert specialists were consulted to assess the validity of the questionnaire and the indicators for measuring resilience, and finally, the validity of the measurement instrument was confirmed by them. Regarding reliability, Cronbach's alpha coefficient was employed to calculate the reliability or dependability of the measurement instrument. Furthermore, the managerial-institutional resilience of local communities exposed to flood risk within the hydrological units of the Sang Sefid watershed was assessed using one-way analysis of variance (ANOVA) and the K-means cluster analysis method. The comparison of the two methods—one-way ANOVA and K-means cluster analysis—demonstrated a significant convergence in assessing the managerial-institutional flood resilience potential of the hydrological units. The identification of Units S-int3 and S9 as the least and most resilient units, respectively, in both methods reinforces the internal validity of the findings. Moreover, the similar grouping of the other units into three distinct classes (with the exception of Unit S-int5) reveals a clear pattern of spatial distribution of resilience across the region, which can serve as a basis for prioritizing management interventions.