Evaluation and analysis of the quality of geomorphology of Qarasu River in the area of Kermanshah city

Urban rivers originated or flew in urban area, Man-made canals which have characteristics of natural rivers, are types of urban rivers as well. The urban river landscape is an important physical element and a kind of ecological corridor in urban landscapes. River corridors play important roles such as providing habitats, acting as filters and barriers, being water sources and water sink and etc (Forman and Godron, 1986). They also increase supply water resources and transportation ways, urban landscape diversity. Moreoverurban rivers enrich the life of urban citizens and contribute to stability, comfort, and sustainability in urban development (Cook, 1991; Baschak LA, Brown, 1995). Due to heavy disturbances throughout the urbanization process, urban rivers have become one of the most intensively influenced areas in the interaction between humans and natural processes. Human activities have drastically changed the structure and function of urban river landscape (Yue, 2012). Many methods have been presented to evaluate and monitor the morphology of rivers, which have variations in terms of concepts and goals. One of the most recent of these methods is the Morphological Quality Index (MOI) presented by Rinaldi et al. in 2013. MQI method was assessment the morphologycal quality of many rivers such as Ahr river in Italy (Campana et al., 2014), Cecina River in Central of Italy (Rinaldi et al., 2017), 122 rivers in Greec (Stefanidis et al., 2022), Lawej river (Esmaeeli and Valikhani, 2014), Taleghan River (Nosrati et al., 2019 and Rezaei et al., 2023) all in Iran.

In this research, an attempt will be made to investigate the geomorphological condition of the Qarasu River in Kermanshah by using the Morphological Quality Index (MQI) and evaluate the ability of this index to analyze the geomorphological conditions of the urban river. Finally, according to MQI method the difference between the goals of geomorphologists and municipal planners and experts  are going to compare and analyze.According to Rinaldi et al. (2013) we assessed three different hydromorphological features, i.e.,Geomorphic functionality, which is based on the observations of fluvial landforms and processes.Artificiality, which expresses presence, frequency, and spatial continuity of anthropogenic structures and/or activities, which could affect the considered river morphological parameters;River channel changes.We then calculated the Morphological Alteration Index (MAI) as follows (Rinaldi et al., 2016) MAL=S totS max Where Stot is the sum of the scores and Smax is the maximum possible deviation for the given stream typology. The MAI is equal to 1 in a completely unaltered river, while it is equal to 0 in a completely altered river. The final step was the assessment of the Qarasu River morphological quality by means of the calculation, for each RR, of the Morphological Quality Index (MQI), as follows:MQI=1-MAL
Based on the MQI values for each RR, we defined the Morphological Quality Classes according to Rinaldi et al. 2016.

Firstly, we divide Qarasu river into 5 segments with variable reaches. In the next step, according to the evaluation parameters of each index in the MQI model, and using field visits, satellite images, and analysis of historical aerial photos, each of the study areas was classified into A, B, and C classes. Then the selected segments of Qarasu River in Kermanshah city were scored. Finally, by using the algebraic sum of the points obtained in each interval as well as the total scores of class C (the condition of the river is in a very bad state) and using relations 1 and 2, MAL and MQI indices were calculated for each interval. The results of examining the selected intervals according to the indicators measured in the Morphological Quality Index method are presented in Table 4. According to table 4, only the first segments of Qarasu River in Kermanshah is in poor condition and other segments of the study area are in good condition. It is noteworthy that fourth and fifth Segments are almost in the same conditions and their scores are equal to 0.76. The second segment has the highest score (0.79). Moreover, the field surveys showed that human activities such as construction waste were observed in the Qarasu River in the first and second segments. The goals and priorities of experts and planners of municipalities in urban areas are issues such as citizens' health and safety, protecting the city against floods, communication between the sides of the river, preserving the visual beauty of rivers and finally paying attention to the aspect of tourism. While in the purely geomorphological view of rivers, any interference and possession in the course of rivers is considered to disturb the balance and is not allowed (table 5).

Due to the supply of agricultural water in the region, the favorable weather and passing through the city of Kermanshah, changes have been made in the bed and channel of the Qarasu River. On the other hand, the bed of this river has changed with the passage of time due to the discharge of construction waste on the side of Qarasu River in Kermanshah city. Therefore, it is necessary to evaluate the Morphological Quality Index of Qarasu River in Kermanshah city. In this regard, Qarasu River in Kermanshah city was divided into 5 segments. The scores of ranges using the Morphological Quality Index method showed that the first segment is in poor condition and others are in good morphological conditions. Also, the field survey showed that in the second segment of Qarasu River, the dam of this river has been destroyed, construction waste in the river and there are grooves along the river. As a result, the Morphological Quality Index is not successful in identifying the condition of the second segment of the Qarasu River. It seems that this model should be used more accurately and sensitively in the evaluation of rivers in urban areas. It is suggested that during the planning regarding the restoration and protection of rivers in urban areas, in addition to the attention and use of structural methods, special attention should be paid to the natural conditions of the river channel in the upstream, the city environment and the downstream flow.