Abstract
Floods are one of the most important natural disasters, causing more damage to humans than other disasters such as drought and famine. These damages increase when they occur in human centers such as cities. Land leveling, encroachment on rivers and canals, changes in natural drainage patterns are also factors that may exacerbate potential damage, flooding of roads and increase maintenance costs, and ultimately flooding urban areas. Sometimes these areas, such as the city of Tehran, have undergone their development, in which case the proposed solution is optimal urban flood management. In the field of urban flood management, determining the places that have the highest rate of production of runoff and runoff is one of the basic necessities (preparation of zoning map of intensity and type of flood). Therefore, in this research, the probable accident hotspots of the bridges located in the main canals of surface water collection in the area of District 5 of Tehran Municipality were identified by HEC-RAS and ASSA hydraulic modeling. Analysis of the capacity performed in relation to the critical points located in the network includes reviewing the flow capacity of discharge through the section of bottlenecks built on the network channels as well as the amount of their capacity shortage and the percentage of filling of the upstream channel for discharge flood with return period 10, They were 25, 50 and 100 years old. The results showed that the flow out of the canals and the insufficient capacity of these canals at the intersections with the bridges in the return periods over 25 years old were insufficient.
