Assessment of Drainage Network Configuration Using Gibbs’ Model with Increased Number of Flow Directions

Stochastic channel network modeling is an informative tool to replicate river networks for the purpose of understanding the variability of geometry and distinguishing observed patterns in networks. In contrast, the application of stochastic network models to artificial or urban drainage networks is not common despite their practical implications for engineering purposes. Gibbs’ model is a useful tool to investigate the network characteristics of drainage networks and also has an advantage to produce alternative networks with the same network characteristics due to its stochastic nature as a network model. This study utilized Gibbs’ model to estimate the network configuration of urban drainage networks in Seoul, South Korea, with an increased number of flow directions from four (N, E, S, W) to eight (N, NE, E, SE, S, SW, W, NW), which enables improved accuracy. Based on that, the network configuration affects the hydrological response directly, the results of this study imply a new design criterion which concerns the connection of upstream and downstream subcatchments with different network configurations to mitigate downstream flooding. Additionally, in order to evaluate the model’s usefulness to be employed to estimate the hydrologic responses of actual drainage networks, the width function-based IUH (WFIUH) was applied to a highly urbanized and pipe-networked catchment of the Shinweol Watershed in Seoul, South Korea.