Document Type : پژوهشی

Authors

• Reza esmaili ¹
• Niusha Nourizadeh Nesheli ²

¹ UMZ

² University of Mazandaran

Abstract

Rivers are natural systems that have undergone significant changes in their morphology due to human pressures over the past decades. The factors influencing river morphological changes and their responses vary across different regions. Consequently, in the present study, morphological changes in a section of the Haraz River in of Amol city were investigated over a 53-year period (from 1968 to 2021).The changes in river width, planform, and riverbed landforms were examined using aerial photographs and satellite imagery. Subsequently, by calculating the specific stream power and conducting field observations, the hazards associated with the river channel were identified. In 1968, the average river width was measured at 141 meters, but by the years 2006 and 2021, it had decreased to 55 meters. The area of riverbed landforms, including the active riverbed and longitudinal bars, decreased by 50% and 95%, respectively, during this period. The river channel transitioned from a braided pattern to a single-channel pattern due to channel narrowing and significant reduction in longitudinal bars. These changes led to an increase in stream power and erosional processes, resulting in river incision and bank erosion. Key factors contributing to the morphological alterations in the study area included the reduction in base flow, irrigation channel diversion, and land use changes along the river margins. Considering the observed trends, the construction of a new dam (Haraz Dam), continued exploitation of floodplain areas, and channelization could exacerbate the risks associated with the river channel and lead to significant floods.

Keywords

• River morphological changes
• River planform
• Haraz River
• Amol
• northern Iran

Main Subjects

• Geomorphology