Investigation of the Potential Threat of Urban Flood at Mountainous Areas through Low Impact Development Techniques (Case Study: Ardabil City)

Mountainous areas are highly exposed to storm rainfalls due to the climate conditions in these regions. The current study mainly aimed to identify the channels and potential regions for inundation and flooding in Ardabil, a mountainous city in Iran, using molding capabilities of the SWMM software. Additionally, the functionality of low-impact development (LID) techniques in decreasing the floods of urban mountainous areas (Ardabil city) was investigated. In this research, the existing conditions in the study area, including the region’s slope, the dimensions of the surface run-off collection channels, and the surface water disposal method, were evaluated by reviewing the existing reports and conducting field visits. To calibrate and validate the SWMM model outputs, the amount of rainfall and run-off height within the channels settled in the basin were field-measured during two storm rainfall events. In the current research, green roof, porous asphalt, infiltration trench, and rain barrel scenarios were applied as the LID techniques. In the section of single scenarios, a green roof was the most effective one reducing the run-off by 12%. In the combination of green roof and porous asphalt scenarios, the run-off water volume dropped by 19%. Finally, by combining all the LID techniques, a 30% decrease in the run-off volume was observed. This study also revealed that the use of LID techniques in combining scenarios is superior to the application of single scenarios. Meanwhile, a combination of two scenarios is preferred owing to the ease of implementation.