Deriving Optimal Analysis Method for Road Surface Runoff with Change in Basin Geometry and Grate Inlet Installation

Road surface-runoffs have been analyzed using various approaches, but inaccurate analysis methods lead to overestimation of the drainage capacity, causing unexpected flood damage in low-lying urban areas. Previous studies highlighted importance considering parameters for accurate road surface-runoff analysis. This study involves an enhanced approach simplified and modified basin geometries, surface gutter flow travel times, inlet interception efficiency as key under conditions. The topographical conditions were set follows: Width (6 m), longitudinal slope (2–10%), (2%), transverse (2–7%). results show that a estimating actual path length time is better than rectangular basin. Additionally, runoff should consider roadside installation conditions, given bypass discharge (i.e., rainfall not intercepted by upstream inlets) flows downstream affects characteristics. Based on these results, optimal method was developed, which expected be useful design.