نشریه هیدروژیومورفولوژی
پیاپی 31 (تابستان 1401)

Identification of landforms and the way of their distribution is one of the basic needs in applied geomorphology and other environmental sciences and landform maps show the shapes of the earth's surface. This project aims to identify the landforms of the Qaranqu catchment area using object-oriented classification methods including nearest neighbor algorithm and thresholding. Landsat satellite imagery for 1990 (TM) and 2020 (OLI) was used for this purpose. First, to apply the classification, atmospheric and radiometric corrections were applied to the images, then to better identify and extract the phenomena, principal component analysis (PCA), and MNF algorithms were used to classify satellite images using classification methods. Object-oriented, which included the nearest neighbor method and thresholding was used. For the accuracy of the maps produced using the two methods of Kappa index and the overall accuracy of the use, the results revealed that the nearest neighbor method is more accurate than the thresholding method. The classification results showed that the highest rate of decreasing changes during 1990-2020 is related to dense rangeland because it has decreased by 12.49 percent and the highest rate of incremental changes is related to irrigate agriculture which is 10.83 percent. The most important reason for this increase is the construction of Sahand Dam over time. In the absence of well-organized planning and the adoption of appropriate policies, the destruction of rangeland will continue and turning it into arable land, which leads to irreparable environmental and economic losses in the region.

The purpose of this study is to simulate and sedimentation status of Ebro River of Ekbatan Dam in Hamedan using GSTARS 2.1 mathematical model.For this purpose, they measure the hydrodynamic part of the sediment from the water and hydrometry of the measuring station Ebro and data on water level cultivar changes in 2006 and cross-sectional geometric data collected in 2006 and 2019 and sediment transport equations in 13-year production period have been used.Studies show that the cross section of the river is changing from V-shaped to U-shaped from 2005 to 2019..Examination of sedimentation rate during 13 years (2006-2019) shows that the cross-sectional level of the river is about 24.6 cm and using Wyang's sedimentary relationships changed by 22.8 and 20.2 cm, respectively, which indicates a good agreement of the model in the evaluation and Simulation of cross-sectional change due to erosion and sedimentation.Studies show that the values of slope and velocity in the middle of the study area are less than the beginning and more than the end, so the amount of sediment in the middle is more than the beginning and less than downstream of the region.It is recommended to use FLUVIAL 12 and HEC-RAS methods to select and apply the most practical method.

the object-oriented method in preparing the land use map of Darre Rood catchment area using Landsat 5 and Landsat 8 images in a period of 30 years, from 1990 to 2019 and its effects on changes in Darre rood river discharge it placed. The images were classified into fourteen classes and the changes in the area of ​​the classes revealed that the classes of irrigated agriculture, rainfed agriculture, rocky areas, residential areas, gardens and lakes with increased area and barren lands, pastures, forest lands and riverbeds decreased They were. To find out the changes in the river flow trend, SCS method was used which was implemented in SWAT model and according to land use in 1990 and 2019 in SWAT model was determined according to the digital elevation layer of the basin and all the necessary parameters to the model. Which included soil layers and land use changes and climate data were called into the model and two separate scenarios for 1990 and 2019 were used. The results showed that with the change of land use, the amount of CN in the second scenario compared to the first scenario increased by 5% and increased from 02.70 to 5.73, which due to the change in land use in favor of the basin becomes more impermeable to rain. Compared to 1990. Also, due to the increase in the type of vegetation, the amount of deep penetration has decreased from the first scenario to the second scenario from 257.09 to 97.9.

The Tamtaman area is located between 37◦38/00//-37◦44/00//north and 44◦40/30//-44◦59/30// east in northwestern Iran, approximately 15 km northwest of Urmia. This study aims to identify and zoning the potential development of karst in the area of Tamtaman cave in west Azerbaijan province using the AHP method. In this study, the information layers of lithology, tectonics, topography, slope, aspect, hydrology, land use, and climate have been considered as factor maps. The above layers have been called to extract the karst potential model in the GIS environment. Different information layers were classified as Criterion maps by applying expert judgment and assigning the weight of each layer in Expert Choice software and field visits. Finally, according to the obtained weight, the karst development zoning map in the Tamtaman area was obtained. The results obtained in this region exhibited a total area, of 6.68% within the very poorly developed class, 15.64% in the less developed class, 42.50% in the normal developed class, and 35.18% in the developed floor are located. The results show that in the Tamtaman region, the lithological and tectonic factors have the highest weight and are the most important factors controlling potential karst growth, while the land-use factor has the least impact on karst formation.

Groundwater is one of the most important natural resources in arid and semi-arid regions. The purpose of this study is to identify areas that have groundwater capacity and to prioritize the factors affecting it. In this study, 11 indicators affecting groundwater capacity including Slope, Elevation, Aspect, Distance from River, Drainage Density, Distance from Fault, Topographic Wetness Index, and Topographic Position Index, lithology, Land use and Relative Slope Position were used. 30% of the totals of 230 wells were randomly placed in the validation data group and 70% in the training data. To prioritize the effective factors and zoning of groundwater potential in Ghorichay watershed, the random forest method was used using ArcGIS and to evaluate the model of relative performance curve (ROC) and Area Under the curve surface (AUC). The results showed that the groundwater capacity of about 8% of the watershed is higher at the outlet of the watershed. According to the VIP diagram, the TWI layer with a value of 0.329 and the distance from the river layer with a value of 0.175 was the most and the least influential factors on groundwater capacity, respectively. The area below the AUC curve showed an accuracy of 87% in the training phase to identify areas with groundwater potential. The result of this study can be used in groundwater management in the Ghorichay watershed.

Ecological indicators have become important tools for evaluating and monitoring natural resources. Understanding the relationship between biological activities and ecological interactions is essential to their structure. On the other hand, human activities have significant effects on landscape evolution through changes in sediment production, transport, and storage. Therefore, this issue should be considered in the comprehensive management of different watersheds and ecosystems. Accordingly, the present study was conducted to evaluate the spatial heterogeneity of the hydro-sedimentologic disturbance index (HSDI) in the watershed located in the central part of Ardabil province. For this purpose, sediment transport (ST), hydrological stress (HS), recharge potential of groundwater (Rec), and soil erosion potential (SEP) were first calculated for 27 different sub-watersheds. Then, these factors were weighted using the Shannon entropy method. The hydro-sedimentologic disturbance index (HSDI) was calculated and zoned using the weighted average. The results showed that the mean, maximum and minimum values of the HSDI index in the Samian watershed were 10.17, 45.67, and 0.20, respectively. In addition, 87.67, 5.33, 5.32, and 1.68% of the watershed area were classified into very low, low, medium, and high levels of disturbances, respectively. Sub-watershed 19 located in the northern part, and sub-watersheds 20 and 21 located in the central part of the Samian watershed have the most disturbances, so they are prioritized for management actions. The present research framework can be used as a potential tool to support decisions that should focus on improving natural resource management.

In rivers, sediment load monitoring is mainly confined to suspended load measurement; as a result, maximizing resources and reducing the damage caused by river flow is critical. The goal of this study was to use Mike3D.2018 software to create a three-dimensional simulation of the Kashkan river flow in the spring of 2019. For this objective, HEC-RAS5.0.7 software is introduced and input according to the production of altitude cultivar (coming from mapping) from the bed and floodplain of the analyzed river with a length of 1200 meters and a scale of 1: 1000 for numerical modeling. Flood, suspended sediment, and transition sediment were estimated using data from the Kashkan-Poldakhtar hydrometric station for return periods of 25, 200, 1000, and 1250 years. Floods were highest at 1200 and 1100 cross sections and lowest at 50 and 350 cross sections, according to the model's findings. By comparing the values with the observed values, it was discovered that the simulation at Kashkan-Poldakhtar hydrometric station performed better. Total sediment simulated 207.45 million tons per day and suspended load utilizing Young’s relation with + 11.87 percent error. The amount of transitional suspended sediments in April (5132779/31) was also higher than in January (9890/55), February (41083/73), March (149629/75), and May (15/112617), according to the findings. In addition, compared to the typical silt in the Kashkan River, the amount of sediment in this month is quite large.

The river plume can be categorized into two general types surface-advected and bottom-trapped and also intermediate type. The river plume classification affects seawater's biological and non-biological characteristics in the river mouth. Given the importance of this issue, using numerical simulations, the plume type of the Arvand river was revealed in this study. The river plume has apparent effects on seawater characteristics of the northwest of the Persian Gulf. For this purpose, the FVCOM model is used for the temperature, salinity, and circulation modelling of the Persian Gulf's water. The model used a horizontal grid of variable triangular elements and a vertical network with 20 Sigma layers. Temperature and salinity at the open boundary were used from the outputs of the HYCOM model. Also, four main tidal components were applied to the model in the open border. After model stability, water column stratification and the shape and width of the river plume were investigated. Several different regional winds were applied to the model to study the wind effect on the plume structure. In no wind, the plume was inclined to the south. The shape and width of the plume change with wind; Thus, the difference between the area of the plume in the two wind modes of 4 meters per second north and south is 300 square kilometres. According to this apparent stratification and the powerful influence of the wind on the plume, the Arvand river has a surface-advected plume that is significant in the fishery, environment, and contamination aspects.