Validation of flood risk maps using open source optical and radar satellite imagery

Abstract

Flooding is a major issue in many countries, affecting many communities and livelihoods (Olsson et al., 2014), and, despite major investments in flood protection schemes, it remains a major issue in Europe (Kundzewicz et al., 2014). Many parts of Europe have been affected by floods in recent decades, causing loss of life and damages on the order of multiple billions of euros (Kundzewicz, 2012; Kundzewicz, Pińskwar, & Brakenridge, 2013). In Spain, the economic impacts of floods have increased in recent decades, a trend that some have associated with a changing climate (e.g. Barredo, Saurí, & Llasat, 2012). With the magnitude of floods projected to increase under climate change for the Iberian Peninsula (Alfieri, Dottori, Betts, Salamon, & Feyen, 2018; Roudier et al., 2016), further damage and economic disruption caused by flooding is expected. A national flood risk assessment (http://www. conso rsegu rosdi gital.com/en/numer o-03/front-page/flood-risk-manag ement-plans), which was conducted as a

Characterization of the 2014 Indus River Flood Using Hydraulic Simulations and Satellite Images

“…Flood mitigation is based on flood risk maps. The drawing of those maps is often based on the outputs of a hydrological model, which requires a digital elevation model (DEM) to represent the topographical surface and define a flood pathway [8]. A DEM can take the form of a digital terrain model (DTM) or a digital surface model (DSM).…”

“…Flood risk mapping has seen the development of new applications over the years, notably the integration of hydrological models with RS in a geographic information system (GIS) [12]. The literature abounds in the use of GIS and RS in flood hazard mapping, for example [13][14][15][16], and more recently on using optical and radar satellite images to validate flood risk maps, for example [8]. Research in GIS and RS has since expanded from what was essentially the delineation of areas at risk of flooding to real-time monitoring of a flood and assessment of its impacts on population and infrastructure [17], and time and cost-effective crop loss assessment after a flood [18], notably for insurance purposes [19].…”

Highlighting recent trends in open source geospatial science and software

“…In the second study, Quirós and Gagnon (2020) present a method for comparing flood‐prone areas using open source optical and radar satellite imagery. The results confirm the accuracy of the flood risk maps based on open source remote sensing imagery and hence demonstrate the potential of publicly available and freely distributed remote sensing data in their development.…”

Newspapers as a validation proxy for GIS modeling in Fujairah, United Arab Emirates: identifying flood-prone areas

“…There is now a better chance of tracing back flooded areas because of the increase in the number of satellites. Quirós and Gagnon (2020) validated flood risk maps using open-source optical and radar satellite imagery. They used normalized difference vegetation index (NDVI) based on the principles that water absorbs the energy in the red band and that clear water has a negative NDVI value (− 1) and thus appears black in the processed satellite image.…”

“…They used normalized difference vegetation index (NDVI) based on the principles that water absorbs the energy in the red band and that clear water has a negative NDVI value (− 1) and thus appears black in the processed satellite image. However, in many cases, flooded areas may not be captured by satellites due to temporal resolution, nature of the flood (the deluge caused by flash floods lasts for a few hours), size of the flooded area, or cloud cover (Quirós and Gagnon 2020). Therefore, newspapers reports could be used to trace back flooded areas.…”