Case Study of Urban Flood Inundation—Impact of Temporal Variability in Rainfall Events

Sun

et al. 2022

Water

Debris flows induced by heavy rainfall are a major threat in Northwest and Southwest China, due to its abrupt occurrence and long runout. In light of this, this work presents the runout simulation and risk assessment of the Boshuigou debris flow under different rainfall conditions in Wudu district, Gansu Province, Northwest China. Based on field reconnaissance, the geomorphological feature and main source of the Boshuigou debris flow were described. With the application of the FLO-2D simulation, the potential flow depth and flow extent of the Boshuigou debris flow under 100-year return-period rainfall and 50-year return-period rainfall were calculated. The maximum flow velocities of the Boshuigou debris flow under the 100-year return-period rainfall and 50-year return-period rainfall were 5.46 and 5.18 m/s, respectively. Accordingly, the maximum flow depths were 5.85 and 5.57 m. Then, the hazard zonation was conducted in combination of the construction and other properties within the potential impact zone, and the risk assessment of the Boshuigou debris flow under the 100-year return-period rainfall and 50-year return-period rainfall was finally completed. This work presents a method for debris flow risk assessment considering the solid source and water flow, which can provide a basic reference for mitigation and reduction of geohazards induced by torrential rainfall.

Section: Fluid Feature Of the Debris Flowmentioning

confidence: 99%

Hazard Zonation and Risk Assessment of a Debris Flow under Different Rainfall Condition in Wudu District, Gansu Province, Northwest China

Sun

et al. 2022

Water

“…In cases where near-real-time or forecasted flood mapping is needed for mitigation and recovery efforts, hydrodynamic models can be used. Many hydrodynamic models have been employed for flood mapping such as 1 and 2 dimensional HEC-RAS models (Farooq et al, 2019;Salman et al, 2021;Tamiru and Dinka, 2021;Namara et al, 2022;Vashist and Singh, 2023), LISFLOOD-FP (Amarnath et al, 2015;Rahimzadeh et al, 2019;Rajib et al, 2020;Nandi and Reddy, 2022), and FLO-2D (Haltas et al, 2016;Erena et al, 2018;Cruz et al, 2019;Li et al, 2021) to name a few. These models are commonly used in practice and provide the basis for some of the flood risk information sources mentioned above.…”

Section: Introductionmentioning

confidence: 99%

Optimizing Height Above Nearest Drainage parameters to enable rapid flood mapping in North Carolina

Richardson,

Beighley

2024

Front. Water

Surface water flooding represents a significant hazard for many infrastructure systems. For example, residential, commercial, and industrial properties, water and wastewater treatment facilities, private drinking water wells, stormwater systems, or transportation networks are often impacted (i.e., in terms of damage or functionality) by flooding events. For large scale events, knowing where to prioritize recovery resources can be challenging. To help communities throughout North Carolina manage flood disaster responses, near real-time state-wide rapid flood mapping methods are needed. In this study, Height Above Nearest Drainage (HAND) concepts are combined with National Water Model river discharges to enable rapid flood mapping throughout North Carolina. The modeling system is calibrated using USGS stage-discharge relationships and FEMA 100-year flood maps. The calibration process ultimately provides spatially distributed channel roughness values to best match the available datasets. Results show that the flood mapping system, when calibrated, provides reasonable estimates of both river stage (or corresponding water surface elevations) and surface water extents. Comparing HAND to FEMA hazard maps both in Wake County and state-wide shows an agreement of 80.1% and 76.3%, respectively. For the non-agreement locations, flood extents tend to be overestimated as compared to underestimated, which is preferred in the context of identifying potentially impacted infrastructure systems. Future research will focus on developing transfer relationships to estimate channel roughness values for locations that lack the data needed for calibration.

Susceptibility assessment of geological hazards in Shenzhen Town, Ninghai county based on the APH-CF model

Han,

Li,

Hui

et al. 2024

Front. Earth Sci.

IntroductionThis work employs a coupled evaluation model that integrates deterministic coefficients with the Analytic Hierarchy Process to conduct a comprehensive assessment of geological disaster susceptibility in Shenzhen Town, Ninghai County.MethodsCascading geological disasters induced by typhoons and rainfall in the southeast coastal area of China are a major concern and cause huge losses of life and property every year. To effectively prevent and mitigate such disasters, it is necessary to evaluate the susceptibility of geological disasters. Taking geological disasters in Shenzhen Town, Ninghai County as the research object, eight influencing factors in terms of topographic and geomorphological conditions, engineering geological conditions, and human activities were selected based on the geographic information platform (GIS) in this work. The coupling model of the certainty factor model and analytic hierarchy process method was used to evaluate the susceptibility of geological hazards in the study area.ResultsThe evaluation results illustrate that the coupling model can accurately and objectively assess the susceptibility of geological hazards in this region, with a high evaluation accuracy of 80.8%. The susceptibility is greatly affected by slope, stratigraphic lithology, and human activities. The areas with extraordinarily high and high susceptibility were identified in the northwestern part of the study, where the ignimbrite is exposed in the steep topography.DiscussionThe research method provides a reference for evaluating the susceptibility of geological hazards in the southeastern coastal region of China, and the evaluation results can provide recommendations for decision-making on disaster prevention and mitigation in this region.