Analysis of Infiltration-Based LIDs for Runoff Control Along Roadways

Abstract Submission: The expansion and renovation of urban roads face the challenges of stormwater management when impervious surfaces are replacing more and more natural vegetation. As a result, the amount and peak value of surface runoff have increased significantly. Low-impact development (LID) is an effective and widely used method to reduce surface runoff in urban constructions. Three types of infiltration-based LIDs along roadways were studied regarding their performance on runoff control: bio-retention cells, rain gardens, and infiltration trenches. Infiltration swales are bio-retention cells placed along vegetative channel bottom and include three layers: surface layer, soil layer, and storage layer. The rain garden contains the surface layer and soil layer, and the infiltration trench contains the surface layer and storage layer, then allowing runoff to infiltrate the native soil. To comprehensively analyze the surface runoff control and infiltration capacity of the three LIDs under different rainfall conditions, the USEPA Storm Water Management Model (SWMM) was used to simulate these three types of LIDs under design rainfall and long-term rainfall events. SWMM can simulate and report detailed results in each layer (infiltration/percolation/seepage rates, soil moisture, and depths). The detailed analysis provides a comprehensive understanding of how different LIDs retain rainwater under different rainfall conditions, thereby reducing surface runoff. The infiltration trench performs best in reducing surface runoff; however, it is classified as an injection well in some states subject to more rigorous environmental regulations. Appropriately designed bio-retention cells/swales are the most suitable for roadway projects. The results of this study have specific practical significance, understanding the mechanism and limitations of different LIDs along roadways on reducing surface runoff and utilizing storage capacity under different rainfall conditions.

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