Assessing flood risk for urban areas in the lower don river using GIS and remote sensing

Increasing urbanization rates and related colonization of traditionally unoccupied and potentially unsafe territories may result in great economic and human losses. In order to ensure resilience of growing and expanding communities, it is necessary to understand both existing risks and potential threats coming from natural and anthropogenic factors. The expansion of urban areas into the Lower Don River floodplain (Rostov Oblast, Russia) is a good example of such processes. Flood events were common for the region, and even after the construction of the Don Dam complex and significant regulation of the river discharge, the risk of inundation still exists. Historically, regular flooding was not considered as a disaster by local communities. However, ongoing floodplain urbanization changes the perception of floods and requires assessing its risks for settlements and economic activities. Assessment of the flood risk was conducted for the region using remote sensing data and GIS. The aim was also to explore the scale and dynamics of floodplain urbanization. In order to evaluate the land cover changes and urbanization rates, Landsat satellite imagery was collected, processed and analyzed for two years 1985 (Landsat 5) and 2013 (Landsat 8). The obtained results have been compared to regional statistical data. Urban growth has been identified in the study area despite the decrease in the total population of the Rostov Oblast. Assessment of flooding risk for urban areas was carried out using the FLO-2D flood routing model (FLO-2D Software, Inc.) and verified using the records of the recent floods. Five flooding scenarios including natural 100-year flood were formulated and tested. The settlements potentially threatened were identified for each of these scenarios.