Performance Analysis for Road-Bioretention with Three Types of Curb Inlet Using Numerical Model

Abstract

The FullSWOF-ZG (Full Shallow Water Overland Flow with infiltration determined by Zones and Grate-inlet submodules) program was used to simulate the road-bioretention (RB) stripe and evaluate the performance of the RB stripe with three types of curb inlet. The program was revised from the open-source FullSWOF-2D program and the validation results indicated FullSWOF-ZG predicts the RB stripe performance accurately. The model cases of 27 RB with different longitude slopes (S0), cross slopes (Sx), and curb inlet lengths (Lci) for the undepressed, composite depressed, and local depressed curb inlets were established in this study. Therefore, 81 cases in total were simulated to explore the curb inlet type and design parameter’s influence on the RB stripe performance. Overall, it was found that the bioretention control efficiency will increase with the S0 decrease, Sx increase, and Lci increase. The composite depressed curb inlet was the most efficient to intercept the road runoff into the bioretention strip, the next best is the local depressed curb inlet, and the undepressed curb inlet was the least efficient. The curb inlet and grate inlet combination in composite depressed curb inlet cases were able to deal with all the road surface runoff for the small longitudinal slope (S0 = 0.1% and 0.3%) to relieve the road local flood inundation.

Lab-Scale Physical Modelling of Common Drainage Inlets for Better Management of Runoff from Road Surfaces

“…On the other hand, the lowest depth of stagnant runoff water was observed in the case of rectangular inlets without any grating (Figure 6). In a computer simulation study conducted by Li et al [13], it was observed that the composite depressed curb inlet was the most efficient to intercept the road runoff, the next best is the local depressed curb inlet, and the undepressed curb inlet was the least efficient. A combination of a curb inlet and grate inlet can intercept almost all of the road surface runoff even for small longitudinal slopes (0.1-0.3%) with a composite depressed curb inlet to reduce water level from the road surfaces.…”