Stormwater Management & Green Infrastructure: Hydrological Modeling, Runoff Retention Kinetics, and Sustainable Drainage Mechanics
Sustainable stormwater management integrates Low Impact Development (LID) techniques and Green Infrastructure (GI) to manage urban surface runoff at its source. Urbanization replaces natural permeable landscapes with impervious surfaces (such as roads, roofs, and pavements), significantly decreasing infiltration capacities, reducing lag times, and escalating peak storm discharge rates. Peak surface runoff flow rate ($Q_p$) for small urban catchments is estimated using the classic Rational Method equation: $$Q_p = \frac{C \cdot I \cdot A}{360}$$ Where $Q_p$ is peak runoff rate ($\text{m}^3/\text{s}$), $C$ is the composite dimensionless runoff coefficient, $I$ is average rainfall intensity ($\text{mm/hr}$) for a duration equal to the catchment time of concentration ($t_c$), and $A$ is catchment area ($\text{ha}$). For heterogeneous catchments comprising $n$ different surface types, the composite runoff coefficient ($C_{\text{comp}}$) is evaluated as: $$C_{\text{comp}} = \frac{...