A New Rapid Simplified Model for Urban Rainstorm Inundation with Low Data Requirements

Ji Shen,Xiaofei Liu,Zhong Tong,Fei Yan,Jianfeng Zhu

doi:10.3390/w8110512

Abstract

This paper proposes a new rapid simplified inundation model (NRSIM) for flood inundation caused by rainstorms in an urban setting that can simulate the urban rainstorm inundation extent and depth in a data-scarce area. Drainage basins delineated from a floodplain map according to the distribution of the inundation sources serve as the calculation cells of NRSIM. To reduce data requirements and computational costs of the model, the internal topography of each calculation cell is simplified to a circular cone, and a mass conservation equation based on a volume spreading algorithm is established to simulate the interior water filling process. Moreover, an improved D8 algorithm is outlined for the simulation of water spilling between different cells. The performance of NRSIM is evaluated by comparing the simulated results with those from a traditional rapid flood spreading model (TRFSM) for various resolutions of digital elevation model (DEM) data. The results are as follows: (1) given high-resolution DEM data input, the TRFSM model has better performance in terms of precision than NRSIM; (2) the results from TRFSM are seriously affected by the decrease in DEM data resolution, whereas those from NRSIM are not; and (3) NRSIM always requires less computational time than TRFSM. Apparently, compared with the complex hydrodynamic or traditional rapid flood spreading model, NRSIM has much better applicability and cost-efficiency in real-time urban inundation forecasting for data-sparse areas.

Highlights

With the acceleration of urbanization, cities have become the material basis of the survival and development of people
From the simulation results of new rapid simplified inundation model (NRSIM), 25 monitoring points were flooded by water from 12 flood sources, of which 18 monitoring points were simulated as flooded points by LISFLOOD
These consistent results reflected that both traditional rapid flood spreading model (TRFSM) and NRSIM were able to simulate the inundation extent with a reasonable accuracy when using a 30-m digital elevation model (DEM) as input data

Summary

Introduction

With the acceleration of urbanization, cities have become the material basis of the survival and development of people. Urban flood disasters have become a growing threat to urban residents. Urban rainstorm inundation is one of the major causes of urban flood disasters. An urban flood event with large inundation extent and significant depth will not merely affect the traffic, commerce, production, government agencies and educational institutions of a city but will seriously damage the security of people’s lives and property. It is becoming increasingly important to design a robust and reliable urban rainstorm inundation model that can reliably provide data references for flood risk management, loss assessment and decision-making in urban flood prevention and control [2]

Methods

Results

Conclusion