Evaluation of one-dimensional and two-dimensional HEC-RAS models to predict flood travel time and inundation area for flood warning system
Ekaraj Ghimire, Suresh Sharma, Niraj Lamichhane
Abstract
The objective of this research is to evaluate the predictive capability of one-dimensional (1D), two-dimensional (2D), HEC-RAS models, for the computation of the travel time of a flood event and its flooding extent. The research was performed in the Grand River of Ohio, USA utilizing the same sets of geometric conditions such as LiDAR data integrated with field-surveyed cross-sections and the same set of flow conditions within the 1D, 2D, and coupled 1D/2D modeling features of HEC-RAS. The analysis suggested that the 2D model consistently outperformed 1D and coupled 1D/2D models. Furthermore, sensitivity analysis indicated that coupled 1D/2D and 1D models are relatively more sensitive than the 2D model to the inputs. The 1D model prediction for travel time was 20% more than the 2D model. Similarly, the inundation area from the 1D model was found to be slightly greater (4.1%) than that of the 2D model.