Runoff behavior on Urban Road intersection based on flow profile simulation

There have been various technologies developed to solve the inundation problem that occurs in almost all urban areas. Some of these technologies, such as low impact development (LID), are developed through the concept of source control. The first step of LID practice is to know the runoffbehavior on a certain surface of an area, following that, the LID practice is then designed. One of the objectives of LID is to decrease inundation depth on the road. This study aims to learn the profile and behavior of storm water flow along roads before they reach an intersection of a road system in Purwantoro region, Malang City, Indonesia. The study design consisted of field measurements and analytical activities as follows: determination of the independent and dependent variables; field measurements and data collection; simulation of flow profiles with various return periods of rainfall using Hydraulic Simulation Model HEC-RAS ver. 4.1; and verification of the simulation result of flow profiles using observation data. This research concluded that slopes on the branch road and runoffdischarge on the main road significantly influenced flow depth at the road intersection. The relationship was expressed by power equations. In contrast, the runoffvelocity at the branch road was more influenced by the discharge on the branch road and the main road, and the relationship followed a linear equation. A further study is required to decrease the runoffdischarge on the road using LID technology such as concrete block pavement as a replacement for asphalt pavement.