Simulating of LID-BMP Methods on Urban Runoff (Case Study: District 22, Tehran)

Nowadays, low impact development (LID) and best management practice (BMP) are being used to reduce the impact of urban development on the runoff quantity. Regarding to this and according to Tehran position and its development, this research was conducted using SWMM model to study the effect of LID-BMP methods on runoff in district 22 of Tehran city, Iran, with area of 54000 ha. This study included five scenarios: current situation, green roof, permeable pavement, vegetative swale and green roof-permeable pavement-vegetative swale. The study was conducted for rainfall in 5 return periods (i.e. 2, 5, 10, 50 and 100 year) in 19 sub-basins.  Results: The results showed that the effectiveness of all methods to reduce runoff was increased up to the return period of 50-yr and then reduced for the 100-yr return period. Green roof and vegetative swale had the most and the least effect on runoff, respectively. In addition, comparison of peak flow of these methods with the results from the Tehran Runoff Management Master Plan revealed that green roof was most effective on the peak flow reduction.