Key Technologies for an Urban Overland Flow Simulation System to Support What-If Analysis

Abstract

Urban flooding poses serious threats to human life. In China, many cities have recently experienced flooding during every rainy season. Several years ago, policies, scientific methods, and engineering measures were applied to address this systematic problem. However, flooding disasters remain frequent in urban areas in China. Therefore, this article discusses the human-earth relationship from a philosophical perspective to analyse the causes of urban water problems. This article mainly illustrates the value of the what-if analysis concept and how to use this concept to address urban flooding issues and improve the management of urban overland flow. However, the existing simulation models and software do not effectively support what-if analyses. In particular, most existing urban hydrological simulation models and software do not sufficiently consider the heterogeneity of geographical objects on urban surfaces and lack interactions to support what-if analyses. These limitations hinder effective implementation of what-if analysis. This article introduces three key technologies that allow an urban overland flow simulation system to effectively support what-if analyses: 1) urban spatial automatic discretization and topo-adjacency, which reflect the heterogeneity of an urban area; 2) hydrological models for the simulation of the hydrologicalprocesses of the main geographical objects in the urban area; and 3) key strategies for a visual analytic platform to support what-if analyses in well-perceived way. The experiment was conducted using a community in Chongqing as a case study. The results demonstrate that the designed key technologies and functions of the proposed system can support what-if analysis and that what-if analysis is an important and useful concept for urban water management.

Stochastic Modelling of Great Letaba River Flow Process

“…Thus, the reliability of a system has to be evaluated under these conditions which are not possible with historical data alone (Otache et al, 2011a). Moreover, it should be noted that the existing simulation models and software do not effectively support scenario analyses (Peng et al, 2018). Therefore, there is a need for a proper tool that can model river system flow to mimic actual physical natural flow characteristics under prevailing conditions.…”

Automated Tool for the Extraction of the Surface Ponds Based on LIDAR Data

“…Lately a series of flood analysis models have been developed, such as: overland flow model which involves a modeling of flow pathways and ponds on the ground surface (Boonya-aroonnet, 2008;Peng et al, 2018), or coupled models -2D which integrates overland and underground flow model (Chen et al, 2005;Dey & Kamioka, 2006;Maksimovic et al, 2009;Son et al, 2016). However, many of the developed models do not take into account the anthropogenic influences on the ground surface such as buildings, roads or land configuration (Peng et al, 2018). The wide availability of different digital data such as DEM (Digital Elevation Model), DSM (Digital Surface Model), LiDAR (Light Detection and Ranging) from low-resolution to high-resolution elevation Digital Elevation Model make it possible to delimit the surface ponds with a high precision and accuracy.…”