Hydrology
Mohammad AKBARINASAB; Faezeh Abbasi; Nadia Talebpour
Abstract
Floods play an important role in the flow of rivers, so their investigation and analysis are importance. Studying the dynamics of floods and the water discharged into the sea (plume) is very important in the fields of fisheries, sedimentation, transportation and environment. Babolrud-River originates ...
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Floods play an important role in the flow of rivers, so their investigation and analysis are importance. Studying the dynamics of floods and the water discharged into the sea (plume) is very important in the fields of fisheries, sedimentation, transportation and environment. Babolrud-River originates from the south of Babol city and flows into the Caspian-Sea after traveling about 67 kilometers. In this research, the expansion of the plume entering from the Babolrud-River to the Caspian Sea during the spring flood of 2018 has been investigated. For this purpose, firstly the images of Sentinel-2 satellite were taken, then the required pre-processing including geometric and radiometric correction was applied. According to the spectral behavior of muddy and clear waters, in the spectral range of wavelengths of 0.4 to 0.78 micrometers, this phenomenon can be distinguished. As a result, by using this feature and the optimal index factor (OIF), the best color combination with the largest information was detected. The combination bands of 3, 4 and 8, with the OIF of 0.19, was defined as the best band combination. In the next step, NDVI, NDFI, and MNDWI were applied, and thresholds were applied to the defined indices for better separation of muddy and clear waters. These thresholds were identified by drawing spectral profiles at the plume of river and checking their histograms. Finally, by building the decision tree with all these indicators and applying the thresholds, the amount of muddy water from the flood entering the Caspian Sea from the Babolrud-River was revealed.
Abbas Einali; Masoud Sadrinasab; Mohammad Akbarinasab
Abstract
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, ...
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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.
