The Evaluation of Hydromorphological Conditions of Taleghan River Using MQI and RQI Methods for Environmental Planning

Rivers face many morphological and ecological changes over time, and these changes are important in environmental and development planning. The Taleghan River in Alborz Province is one of the rivers associated with many morphological and ecological changes in recent years, and for this reason, this issue has been addressed in this study. The data used in the research included library information, information obtained from Google Earth images, information obtained from field visits, as well as the 12.5 SRTM digital elevation model. Research tools also included ArcGIS and Google Earth software, as well as RQI (description and assessment of environmental conditions in riverine areas) and MQI (morphological quality index) models. This research has been carried out in two general stages. In the first stage, the environmental conditions of the studied periods have been evaluated using the RQI method, and in the second stage, the river dynamics of the periods has been investigated using the MQI model. The results obtained from RQI method have shown that intervals 1, 2, 3, 4, 5 and 6 with 46, 67, 69, 64, 44 and 43 points, respectively, have a poor status and intervals 7 and 8 They also have an average position with 74 and 76 points, respectively. Also, the results of the evaluation of the dynamic condition of the river have shown that intervals 1, 2, 3, 4 and 5 with coefficients of 0.188, 0.156, 0.156, 0.117 and 0.242, respectively. Very poor morphological dynamics, interval 6 with a coefficient of 0.453 in terms of MQI index has a weak dynamic state and also intervals 7 and 8 with a coefficient of 0.477, have the highest coefficient and in terms of geomorphological dynamics have more dynamics than the other intervals.
 
Extended Abstract
1-Introduction
Rivers are dynamic systems. They change over time under the influence of various factors such as human activities. Morphological and ecological changes in rivers are important for environmental planning and development because these changes cause changes in the amount of sediment, and erosion of banks and facilities near the riverbed. In recent years, rivers have faced many morphological and ecological changes due to the lack of proper management. Human activities such as urban development, agriculture, industry, etc. have caused the physical and chemical characteristics of rivers to change and affect the ecological status of the river. Human impacts on the river without the necessary information will be associated with ecological and morphological changes in the river. Humans directly and indirectly affect processes and accelerate natural change in the river. The most important cases in this regard are the improper use of water resources, agricultural and industrial development, dam construction that causes severe evaporation of water and more sedimentation in rivers, limiting the river channel in long distances, creating multiple bridges with foundations inside the river and pouring municipal and industrial effluents and pointed. The importance of the river issue, especially ecological changes and the morphological dynamics of rivers has led to be addressed in this study. In this paper, using RQI and MQI models, the ecological status and morphology of Taleghan River is evaluated.
 
2-Materials and Methods
In this study, quantitative and qualitative methods are applied. The data included library resources, information obtained from Google Earth images, data obtained from field visits, and a 12.5-meter Alsopalsar digital elevation model. Research tools included ArcGIS and Google Earth software, as well as RQI (River Quality Index) and MQI (Morphological Quality Index) models. In this study, in order to study the river in the study area, first, based on natural characteristics, the river in question is divided into 8 sections. This research has been carried out in two general stages. In the first stage, using the RQI method and based on quantitative and qualitative information obtained from field visits and satellite images, the environmental conditions of the eight sections have been evaluated. In the second stage, using the MQI model, the dynamics of the river of intervals is investigated.
 
3- Results and Discussion
In this study, to investigate the ecological status and morphological dynamics of Taleghan River based on the natural characteristics of the area, 8 homogeneous sections have been selected and then based on the indicators in RQI and MQI methods, these intervals have been evaluated. Examination of the morphological conditions of the sections indicates that section 1 is located in the mountain unit and has a high limit, but sections 2 to 8 are located in the flood plain unit and have less restriction than section 1. The RQI index indicates that sections 1, 2, 3, 4, 5, and 6, with scores of 46, 67, 69, 64, 44, and 43, respectively, are poor and in need of vegetation regeneration systems. Sections 7 and 8, with 74 and 76 points, respectively, are in average condition and need management measures to improve hydrological and ecological conditions. The results of the evaluation also show that sections 1, 2, 3, 4 and 5 with coefficients of 0.188, 0.156, 0.156, 0.117 and 0.242 have dynamic status, respectively. Morphologically they are very weak. In these sections, there is little dynamics and dynamics of morphology due to narrowing and less involvement of human factors. Sections 7 and 8 with a value of 0.477 have the highest coefficient and have a more dynamic morphology than other sections. Interval 6 with a coefficient of 0.453 for the MQI index has a weak dynamic state.
 
4- Conclusion
The results show that Section 1 is poor in terms of vegetation; also associated with low morphological dynamics because of locating in a high and steep area. But sections 7 and 8 have moderate vegetation because they are located in an area with low altitude and slope. Low slope and the involvement of human factors in these sectors has caused a higher coefficient to be calculated dynamically than other sectors. Accordingly, sections 7 and 8 have a better ecological status than other sections. However, they are subject to changes due to river dynamics and human activities, and it is necessary to take effective management measures in these two areas.