Modeling of Infiltration Wells to Reduce Rainwater Runoff of Buildings: A Case Study in Campus of Polytechnic State of Sriwijaya, Indonesia

Abstract

Rainfall in Indonesia is classified as high, indicated by the average which ranges from 2000-4000 mm/year. This potential, on the other hand, often creates problems as a result of rain falling to the surface which usually only becomes surface runoff, inundation, and flooding. Infiltration wells are rainwater conservation technologies that have been widely applied to reduce surface runoff and at the same time increase groundwater reserves. The case study was conducted at the Sriwijaya State Polytechnic Campus, Indonesia. The purpose of this study was to determine the model of infiltration wells for controlling rainwater runoff which is suitable to be applied in the research area. Based on field testing using a doublering infiltrometer, the infiltration capacity value obtained was 3.42 cm/hour. The infiltration well model used in this case is a cylindrical type of impermeable wall, with a diameter of 1 – 1.4 m and a depth of 1.5 – 2.5 m. The simulation was carried out per 100 m rainfed area (roof of the building) for one infiltration well by referring to daily rainfall data for 12 years (2007-2018). The simulation results show that infiltration wells with a diameter (1.2 1.4 m) and depth (2.5 m) were able to reduce rainwater runoff by 68.3% and occurred 1163 times overflow for 12 years. The simulation also revealed that increasing the diameter was more effective in increasing the amount of rainwater runoff reduced than increasing the depth of the infiltration well.