Integrated Hazard Modeling for Simulating Torrential Stream Response to Flash Flood Events

Abstract

This study aims to monitor the flash flood response of Vidor/Wadore hill torrent in Pakistan by the integration of Personal Computer Storm Water Management Model PCSWMM (hydrologic) and HEC-RAS 5.x (hydraulic) models. The method leverages remote sensing and GIS derive estimates of measured and inferred parameters of Vidor rural catchment to quantify the flash flood events of the last four years: 2014–2017. The calibration of the PCSWMM is performed using the sensitivity-based radio tuning calibration (SRTC) tool. The Nash–Sutcliffe efficiency (NSE), coefficient of determination (R2), and relative error (RE) values were found between 0.75–0.97, 0.94–0.98, and −0.22–−0.09 respectively. The statistical indicators prove the accuracy of PCSWMM for rural catchments. The runoff response of Vidor torrent is also analyzed for 0.5/12.7, 1.5/38.1, and 2.0/50.8-inch/mm rainfall hyetographs. The generated hydrographs are used to simulate 2D-module in HEC-RAS 5.x for floodplain demarcation in the piedmont area. The accuracy of the flood extent is analyzed using spatial overlay analogy in the ArcGIS environment by comparing simulated and historically available flood extents. The simulated flood extent shows 76% accuracy with historic flood extent. The impact of flash flood events shows wheat, maize, and fruit orchards are the most effected agriculture in piedmont area. The results revealed that the integration of hydrological, hydraulic, and geospatial modeling approaches can be used to model a full picture of catchment response during flash flood events.

Integrated Hydrologic and Hydraulic Analysis of Torrential Flood Hazard in Arequipa, Peru

“…The Hydrological Engineering Center River Analysis System (HEC‐RAS) is used around the world for flood depth and hazard prediction (e.g., Stoleriu et al 2019; Munir et al 2020). A digital elevation model (DEM) with a horizontal resolution of 0.5 m and a vertical resolution of 1 m were imported as a terrain layer into RAS Mapper, part of HEC‐RAS 5.0.7.…”

Torrential Flood Water Management: Rainwater Harvesting through Relation Based Dam Suitability Analysis and Quantification of Erosion Potential

“…The major torrents affecting D. G. Khan include Kaura, Vehowa, Sanghar, Sori Lund, and Vidor. The characteristics of torrents including; variation in peak flows, and high sediment yield hardened the management of these torrents [3]. The steep slope mountainous catchment is primarily majorly composed of loam, clay loam, and sandy clay loam.…”

“…The stream locally named "Rod Kohi" is categorized as non-perennial and remains active in monsoonal season. The total length of the torrential stream is approximately 158 km [3,4,34]. The discharge data (Table 1) collected from Punjab Irrigation Department (2010-2019) shows that event concentration is clustered in the monsoon season (June, July, and August).…”

“…These studies presented structural and non-structural management of flood. The structural management considers physical measures including the construction of dams, leaves, floodwalls, and elevated buildings, cleaning of water bodies, and flood proving properties [3,4]. The second possible solution is non-structural, which includes planning for disaster, flood plain zoning, and early warning systems.…”

Geo-Spatial Analysis in Hydrology

“…The model assessment results in Wu et al [22] showed that the integration of spatio-temporal GIS and hydrodynamic models can improve the efficiency of flood risk simulations for decision support, such as dam-break flood simulations and dynamic visual simulations. Munir et al [23] integrated a hydrological model and a hydraulic model based on remote sensing and GIS-derived estimates to simulate torrential streamflow response to flash flood events in Pakistan. The study made use of the integration of GIS and remote sensing technique to derive different hydrological parameters for the models at a pixel level.…”