Design Factors and Procedure for Hydrological Design of Permeable Road Systems

Abstract

The application of permeable pavements is known to be effective in reducing negative impacts such as increase in peak runoff rate and urban heat islands as the impervious surface increases. In this study, a detailed procedure for the hydrological design of permeable road systems and its example are presented. The study was carried out in the order of construction of demonstration-scale permeable road, analysis of rainfall-runoff data obtained from demonstration facilities, verification test of permeable road, construction of numerical design model, analysis of model sensitivity for design factor derivation, and development of the design procedure. The K-LIDM-R (K-LIDM-Road) was constructed as a design model by applying K-LIDM (Korea LID Model) to the permeable road. The model was confirmed by analyzing the data obtained through the empirical experiment, rainfall-runoff monitoring, and numerical model results. The permeable road system was constructed by linking the permeable road with the planter box, infiltration gutter, swale, etc., and the 33 most commonly used types of systems are presented. From the model sensitivity analysis, the height and diameter of the perforated pipe and the length of the unit road, which is the unit length of the perforated pipe connected with the urban stormwater drainage pipe, were identified as the major design elements. The design aims to reproduce the characteristics of the hydrograph prior to development by determining the detailed design values of the design elements and the thickness of the road base layer for a given design rainfall and permeable road system. The data obtained through this study can be used as basic data for the design of permeable roads, and the developed design procedure can be applied to the design of permeable roads connected with Low Impact Development facilities.