Urban Stormwater Control Using Intensity Levels: Assessment of the First Domain (Frequent Rainfalls)

Effective stormwater management requires the implementation of integrated methodologies that ensure the adaptability of the drainage networks to accommodate a large range of inflow rates. The use of intensity-based management approaches, such as 3PA and 3SA, makes it possible to analyze the network under different conditions, from lower-intensity events (frequent rainfall) where on-site control is promoted, to extreme events where the most significant flood-prone areas must be identified. This study focuses on the objectives of the first domain (frequent rainfall), presenting a procedure to assess the performance of the networks. General and specific performance indicators were developed and tested in a real urban drainage network using SWMM and different rainfall events (T = 0.12 y obtained from historical records, and 1/3.T = 2 y and T = 1 y resulting from IDF curves). Results indicate that, even within frequent rainfall events, the selected rainfall method has a significant influence on the performance. General indicators allow the identification of priority intervention zones and help determine whether the network is approaching the domain’s objectives. The specific indicators enable the assessment and optimization of NbS, while the general indicators support their optimal placement to improve overall system performance.