Efficiency of curb-opening inlet with porous asphalt

The retention of rainwater on roads without discharge into stormwater networks leads to reduced road sustainability, as standing or infiltrating water penetrates asphalt and base layers, weakens structural integrity, and causes cracking, potholes, and asphalt-binder stripping, ultimately shortening pavement service life. This problem has many causes, including the hydraulic inefficiency of stormwater inlets in capturing the amount of water present in the road. This paper proposes a new type of rainwater inlet: surrounding the curb-opening inlet with porous asphalt 30 cm wide and 5 cm thick to increase its efficiency and avoid the need to enlarge the inlet size. The water captured from both components (the inlet and the porous asphalt) is collected in the same manhole. Usually, either curb-opening inlets or porous asphalt are used to drain stormwater. In this study, both components were combined and the efficiency of the proposed inlet was compared with that of a conventional inlet (without porous asphalt). The results show that the recommended inlet consistently exhibits higher hydraulic efficiency. Key hydraulic factors affecting performance include the width of porous asphalt layer and the discharge rate. Increased asphalt width and lower discharge rates were found to enhance the inlet's hydraulic efficiency.