The Influence of River Channel Occupation on Urban Inundation and Sedimentation Induced by Floodwater in Mountainous Areas: A Case Study in the Loess Plateau, China

Abstract

River channel occupation has made cities in the mountainous areas more vulnerable to floodwater out of river channels during rapid global urbanization. A better understanding of the influence of river channel occupation on urban flood disasters can serve as a reference in planning effective urban flood control strategies. In this study, taking a flood event that occurred on July 26th, 2017 in a city on the Loess Plateau as an example, field surveys, dynamics detection of the river channel using remote sensing technology, and scenario simulations with a two-dimensional flow and sediment model were utilized to quantitatively analyze the impacts of river channel occupation on urban inundation and sedimentation. The results show that river channel dynamics reduced by construction can be successfully detected using the combination of high-resolution images and Landsat time-series images. The variation of the water level–discharge relationship caused by the narrowing of the river channel and the increase of the flood-water level caused by water-blocking bridges/houses result in a significant reduction of the flood discharge capacity. The contribution of the narrowing of the river channel was 72.3% for the total area inundated by floodwater, whereas 57.2% of urban sedimentation was caused by the construction of bridges/houses within the river channel. Sustainable flood mitigation measures were also recommended according to the investigations and research findings in this study in order to reduce the social, environmental and economic damages caused by floods.

Remote Sensing of Surface Water Dynamics in the Context of Global Change—A Review

“…The remaining studies in this region focus on the anthroposphere. The single largest topic within this group is flood monitoring [31,108,238]. In contrast to other application fields, flood monitoring demands high temporal resolution data.…”

“…Due to the increase in impervious surface area, urban areas are more at risk of being flooded [30]. In highly populated areas, such events often cause high casualties [31] and an increased risk for disease [32] among the local population, as well as the destruction of infrastructure [33].…”

A Model for Calculating the Spatial Coverage of Audible Disaster Warnings Using GTFS Realtime Data

“…The importance of selecting the right tool to be used for assessing the effectiveness of disaster management implementation has been highlighted [37]. The need to build a flood warning system that can easily be accessed and understood by local stakeholders has also been identified [38]. In the future, we aim to package and implement this model and provide it to local stakeholders in high-disaster-risk areas where GTFS data is available to support the implementation of warning distribution systems.…”

Urban Flood Risk and Economic Viability Analyses of a Smart Sustainable Drainage System

“…Instead, drainage networks consisting of pipes and culverts divert surface water to local watercourses. In some cases, this has resulted in downstream flooding and deterioration in river water quality caused when foul sewers are overwhelmed by surface water leading to a release of dirty water into rivers [18][19][20][21]. Drainage systems need to adapt to and manage extreme events including flooding and periods of drought while helping to reduce carbon emissions.…”