Zohreh Talebi; Seyyed Ali Ayyoubzadeh; Hossein Mostafavi; Mohammad Mehdi Hoseinzadeh; Hossein Shafizadeh
Abstract
ABSTRACTBackground and Purpose: Change is an integral part of all river systems. Most rivers now operate under fundamentally different conditions to those that existed prior to human disturbance. Human interventions indirectly change geomorphic processes such as sediment transport, erosion and sedimentation ...
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ABSTRACTBackground and Purpose: Change is an integral part of all river systems. Most rivers now operate under fundamentally different conditions to those that existed prior to human disturbance. Human interventions indirectly change geomorphic processes such as sediment transport, erosion and sedimentation along the rivers, and the spatial distribution and rate of these processes often including profound changes to river morphology. Therefore, it is important to evaluate the morphological quality, especially for the rivers of Iran, which are characterized by a very high level of human pressure. For this reason, In this research, a morphological evaluation from the upstream to the middle of the Talar River (Northern Iran - Mazandaran) using the Morphological Quality Index (MQI) and with the aim of determining changes in its morphological quality has been considered.Materials and Methods: Talar River was divided into two landscape units, three segments and 23 reaches based on the hierarchical approach and according to the physiographic condition. The evaluation of Talar river has been done after drawing and analyzing the spatial units using Morphological Quality Index (MQI).Results and Discussion: The results obtained from 28 MQI parameters in 23 reaches show that about 15% of the reaches have a "good" condition, almost 35% of the reaches have a "moderate" condition, and more than 50% have a "poor" and "very poor" condition, which means significant damage to the river corridor in the reaches. The subject of investigation and the need to pay attention to the corrective solutions and restoration of the river and its banks. Along the Talar River, due to the large amount of agriculture, urban development and road crossing, the reaches that are in the urban area have poor and very poor morphological quality class, and the reaches that are in the forest area, virgin and untouched, have The morphological quality has been evaluated as good. Also, the results of the evaluation indicate that the average quality class of the investigated reaches is in "moderate" conditions.Conclusion: Considering that the urban and agricultural development and sediment collection takes place in the boundary of the river bed and the vegetation cover and the river corridor have been destroyed in most of the reaches, measures such as observing the boundary of the river bed and boundary as well as planting plants On the river bank and removing sediment based on annual yield will help to restore the river in many reaches. In addition, the results of this evaluation have shown that the MQI morphological quality index method can be a suitable and effective tool in diagnosing hydromorphological challenges. Also, the morphological quality index provides the conditions for evaluating the morphological condition, but it is not enough for the general hydromorphological classification alone, and it should be integrated through the use of a special method to evaluate the changes in the hydrological regime.
Amin Fathi Taperasht; Hossein Shafizadeh-Moghadam; Mahdi Kouchakzadeh
Abstract
Introduction: Climate identification and classification have long been of interest to meteorologists. Researchers have classified the earth into homogeneous climatic zones using different methods and climatic variables such as rainfall and temperature. They have used the results of climate zoning to ...
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Introduction: Climate identification and classification have long been of interest to meteorologists. Researchers have classified the earth into homogeneous climatic zones using different methods and climatic variables such as rainfall and temperature. They have used the results of climate zoning to assess water scarcity and water resources on a small and large scale to anticipate practical measures to control drought in vulnerable areas. The purpose of this study is to update and analyze the Spatio-temporal analysis of Iran's climatic classification based on the Domarten index and the Mann-Kendall test. Because in studies based on climate classification maps, up-to-date maps can better help understand the study area.Material and methods: For this study, data related to temperature and precipitation variables were extracted monthly from 153 synoptic stations from 1995-2019 from the Meteorological Organization of Iran. First, the data of average annual temperature and total annual precipitation were obtained from monthly data and then, using isothermal maps, they were obtained using the kriging model. The final climate zoning map was prepared using the De-Martonne index based on rainfall and temperature. The non-parametric Mann-Kendall test was also used to evaluate the significance or non-significance of the De-Martonne climate index and determine the trend.Results and discussion: The results showed that based on the Kriging model, R2 and RMSE for precipitation data were 0.58 and 167.51 mm, respectively, and for the temperature data were 0.83 and 2.23 °C, respectively. This indicates better performance of the model for temperature data. This is related to the high variance of precipitation data in the country. Iran's climatic zoning based on the De-Martonne index showed six main climatic types in Iran. Most of Iran's area has an arid climate and then a semi-arid climate. The study results showed that arid climate is 76.40%, the semi-arid climate is 19.65%, and other climates make up less than 4% of the area of Iran. Also, the area of arid and semi-arid climates with an area of 96.05% of the area of Iran has increased compared to previous research, which may be due to reduced rainfall and increased temperature. Also, the results of the Mann-Kendall test showed that Khorramdareh, Miyaneh, Ramsar, Boroujerd, Piranshahr, Tabriz, and Bijar stations have a significant upward trend (wetting trend), and Dezful, Malayer, Sabzevar, Bandar Anzali, Tehran (Mehrabad), Tehran (Shemiran), Qazvin and Dushan Tappeh stations have a significant downward trend (drying trend) at the significance level of 5%.Conclusion: This study showed that Iran has six climatic regions, including arid, semi-arid, Mediterranean, semi-humid, humid, and very humid. Also, comparing the results with the results of research done by other researchers in the past showed that the area of arid and semi-arid climates in the study period has increased compared to previous periods. Also, 14% of stations with a downtrend (8 stations) have a significant downtrend, and 7% of stations with an uptrend (7 stations) have a significant uptrend at the significance level of 5%.
