Hydrological Topography Data Set (HTD)— the Data Set for High Resolution 2D Urban Flood Modeling

Abstract

This study investigated the demand of data for better high resolution two-dimensional (2D) hydraulic modeling and proposes a data set named "Hydrological Topography Data Set" (HTD for short) for this purpose. Derived from airborne lidar point cloud, the HTD comprises three parts: (1) High Resolution Hydraulic Three-Dimensional Features: high resolution three-dimensional vector data that preserves the locations and elevations of topography breaklines, (2) Hydraulic Digital Elevation Model: high resolution (1 × 1 m) DEM enhanced by the terrain breaklines to preserve the landscape characteristics, and (3) Hydraulic Digital Surface Model: high resolution (1 × 1 m) DSM conditioned by removing the height of vegetation and temporary objects. With HTD, hydraulic features such as drainages with 10 m of width can be identified and properly set up in numerical models, thus can help simulating and access- ing the flood in urban area more in detail. Through case studies we demonstrate how HTD can affect the results of hydraulic modeling. The results show that HTD can help modelers to construct proper mesh (or computational grids) for 2D hydraulic modeling, and pre- serve topography characteristics (i. e., shape and elevation), which improves the modeling results in terms of spatial resolution and physical rationality, while still keeping the computation efficient.