Curve number for runoff estimating in interlocking concrete pavement

ABSTRACT Curve Number (CN) values estimating from rainfall-runoff data is an attractive topic in hydrology. However, CN values are lacking for Interlocking Concrete Pavement (ICP) material, mainly when seated over bare soil (not over a permeable pavement structure). Here, we compute CN values for the ICP seated over clayey soil using measured rainfall and infiltration capacity data. We estimated runoff ( Q) using 32 events of 24-hour rainfall depth ( P 24) and an infiltration model, assuming a hortonian runoff process. To estimate the CN for each P 24 event, we used the rainfall-runoff incremental approach. Overall, we obtained CN values ranging from 52 to 63. The best CN values to estimate Q were equal to 52.2 ( R M S E = 9.09 mm and R 2 = 0.03) and 60.1 ( R M S E = 1.45 mm and R 2 = 0.97), considering natural- and rank-ordered P 24- Q data, respectively. Our results indicate that it is more suitable to use the initial abstraction ratio ( λ) equal to 0.20 for the ICP material. The findings provide a better understanding of the rainfall-runoff process in ICP and help improve the design of stormwater drainage systems.