Curve number for runoff estimating in interlocking concrete pavement

Curva número para estimativa do escoamento superficial em pavimento de concreto intertravado

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 ($RMSE$ = 9.09 mm and $R^2$ = 0.03) and 60.1 ($RMSE$ = 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 ($\lambda$) 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.

Keywords: Paver; Low impact development systems; Stormwater Drainage System; Flooding