Evaluation of the Hydrological Performance of Infiltration Trench with Rainfall-Watershed-Infiltration Trench Experimental Setup

Abstract

Urbanization and population growth result in an increase of insufficient groundwater recharge. In order to overcome the adverse effects of urbanization, low impact development (LID) best management practices (BMPs) are introduced. LIDs are nature-based solutions, also called green infrastructures, that have the ability to control both the amount and the quality of stormwater runoff. Rain barrels, vegetative swale, green roofs, bioretention, permeable pavement, and detention ponds are among the examples of LIDs. Within this context, the infiltration trench is also one of the important LID types and is widely implemented in settlement areas. Field-scale experiments may not be sufficient in determining the design criteria of infiltration trenches. Controlled experiments should be conducted in order to identify the optimum design criteria of infiltration trenches for best practices. In this study, the hydrological performance of the infiltration trench is investigated by conducting experiments using an open-lab large-scale rainfall-watershed-infiltration trench (RWI) experimental setup. The RWI experimental setup is built at the Avcılar Campus of Istanbul University-Cerrahpaşa and consists of an artificial rainfall system, an impermeable drainage area, and an infiltration trench. The effect of gravel size, berm height, and rainfall type on the hydrological behavior of the infiltration trench is tested by conducting several experiments. During these experiments, the overflow rate and the drainage rate are measured at the exit of the pipes, located on the front wall and on the base of the infiltration trench, respectively. Results show that the magnitude and lag time of the overflow rate hydrograph are affected by rainfall intensity, gravel size, and berm height significantly. On the other hand, minor changes on the drainage rate hydrograph are observed under different rainfall intensities, gravel sizes, and berm heights. Based on the outcomes of this study, the engineering design guidelines of infiltration trenches are elaborated.