Flood Management, Characterization and Vulnerability Analysis Using an Integrated RS-GIS and 2D Hydrodynamic Modelling Approach: The Case of Deg Nullah, Pakistan

Abstract

One-dimensional (1D) hydraulic models have been extensively used to conduct flood simulations for investigating flood depth and extent maps. However, the 1D models cannot simulate many other flood characteristics, such as flood velocity, duration, arrival time and recession time when the flow is not restricted within the channel. These flood characteristics cannot be disregarded as they play an important role in developing flood mitigation and evacuation strategies. This study formulates a two-dimensional (2D) hydrodynamic model combined with remote sensing (RS) and geographic information system (GIS) approach to generate additional flood characteristic maps that cannot be produced with 1D models. The model was applied to a transboundary river of Deg Nullah in Pakistan to simulate an extreme flood event experience in 2014. The flood extent images from the moderate resolution imaging spectroradiometer (MODIS) and observed flood extents were used to evaluate the model performance. Moreover, an entropy distance-based approach was proposed to facilitate the integrated multivariate flood vulnerability classification. The simulated 2D flood modeling results showed a good agreement with the flood extents registered by MODIS and the observed ones. The northwest parts of Deg Nullah near Seowal, Dullam Kahalwan and Zafarwal were the most vulnerable areas due to high flood depths and prolonged flooding duration. Whereas high flood velocities, short flood arrival time, prolonged flood duration and recession times were observed in the upper reach of Deg Nullah thereby making it the most susceptible, critical and vulnerable region to flooding events.

Flood hazard mapping and analysis under climate change using hydro-dynamic model and RCPs emission scenario in Woybo River catchment of Ethiopia

“…Hydrologic Engineering Center (HEC)-RAS and HECgeographic river analysis system (GeoRAS) model results show that inundated areas and depths are in close approximation with survey-based inundation results obtained by Japan International Cooperation Agency (Lo et al, 2017). The results obtained would have widespread applications for environmental planners, flood control administration, policymakers and emergency managers and literally would help flood hazard mitigation from study results (Ahmad et al, 2010;Mind'je et al, 2019).…”

2d Simulation of Design Discharge in Flood Hazard Spatial Analysis Using Hec-Ras, (Case Study Mata Allo Sub-Watershed, Enrekang, Indonesia)

“…The depth value shows the uniformity of the location of the flood vulnerability level between return periods. Based on the classification of Ahmad et al (2022) to the depth of flood. The average level of vulnerability in the very low range is ±9.60 Ha, low range is ±8.8 Ha, moderate vulnerability range is ±13.63 Ha, high vulnerability level is ±23.58 Ha, and the level of vulnerability in the extreme range is ±25.71 Ha.…”

“…These results indicate that areas in the Mata Allo Sub-watershed are in the high to extreme range with inundation depths of 2 meters to above 5 meters. This result also includes the value of river depth during flooding according to the HEC-RAS simulation that has been carried out (Ahmad et al, 2022).…”

“…The use of several software such as HEC-RAS is one form of hydraulic model development to address hydraulic problems in detail . HEC-RAS is intended for processing geospatial data, and makes it easy for users to create files containing geometric data, and the results of the formed water surface profile can be used and interpreted in determining the depth and extent of flooding (Ahmad et al, 2022). Hydraulic modeling through HEC-RAS can be interpreted into 2-D modeling, the resulting simulation also provides a more accurate average depth value (Ngo et al, 2023).…”

Assessment of cropland inundation due to the operation of the Reelfoot Lake spillway in West Tennessee

“…A worldwide increase in population has necessitated land‐use changes (Chen et al, 2019; Lopez & Hayes, 1984; McIntyre & Naney, 1990; Shankman & Liang, 2003) which, in combination with the escalating intensity of precipitation and storms fueled by natural and anthropogenic factors, results in increased flood frequency (Ahmad et al, 2022; Allan & Soden, 2008; Li et al, 2013; Pall et al, 2011; Schiermeier, 2011; Shankman & Liang, 2003). Land‐use alterations are particularly problematic downstream from lakes and reservoirs, where hydrologic alterations such as channelization and levee construction reduce the storm buffering capabilities of these waterbodies (McIntyre & Naney, 1990; Nystrom et al, 2018; Shankman & Liang, 2003).…”