Document Type : Original Article
- Zohreh Talebi 1
- Seyyed Ali Ayyoubzadeh 2
- Hossein Mostafavi 3
- Mohammad Mehdi Hoseinzadeh 4
- Hossein Shafizadeh 5
1 Department of Water Engineering and Management, Faculty of Agriculture, Tarbiat Modares University, Tehran, Iran
2 Professor, Department of Engineering and Water Management, Faculty of Agriculture, Tarbiat Modares University, Tehran, Iran
3 Department of Biodiversity and Ecosystem Management, Environmental Sciences Research Institute, Shahid Beheshti University, Tehran, Iran
4 Department of Physical Geography, Faculty of Earth Sciences, Shahid Beheshti University, Tehran, Iran
5 Associate Professor, Department of Water Engineering and Management, Faculty of Agriculture, Tarbiat Modares University, Tehran, Iran
Background 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.