Floodplain Urbanization: The Lower Don River
The frequency of reported severe flood events and associated economic loss has been rapidly increasing in recent years. This trend might be explained by the combination of such factors as climate change and the expansion of urbanized areas into floodplains. The aim of this research was to explore the scale and consequences of floodplain urbanization of the Lower Don River (Rostov Oblast, Russia) and assess related flood damage threats. The environmental security of this area is a matter of great importance since historically flood events were common for the region and even after the construction of the Tsimlyansk Dam and regulation of the water discharge, the risk of inundation still exist.
The Tsimlyansk Dam is regulating the water flow of the Don River since 1952 when the construction of the reservoir was completed. The creation of the reservoir resulted in the smoothing of the river runoff through the year. Still in cases of severe unexpected floods the downstream territories (Lower Don River floodplain) can be submerged (the floodplain was submerged completely in 1963, 1979, 1981 and 1994, in some years it was inundated partially).
The combination of various techniques was used in order to address project objectives: historical data collection, application of the Remote Sensing, GIS, hydrological modeling (FLO-2D flood routing model - http://www.flo-2d.com/). Five scenarios were selected for the simulation of the flood event in the FLO-2D: repetition of the 1917 flood; 1979 flood - for model verification; 20-year flood (5% probability); 100-year flood (1% probability); 1000-year flood (0,1% probability).
It was found that some rate of the urban growth is inherent in the study area. The differences in flood hazard depending on the water discharge were analyzed. The most hazardous areas within the floodplain were defined, by the maximum flow depth and the maximum flow velocity. It was found that generally small villages on the river bank within the wide parts of the floodplain will experience the most intense flood in case of a disaster, together with the territory right under the Tsimlyansk Dam. The results acquired through this project might be interesting for various stakeholders - researchers, urban planners, local population.
Results of the project were presented by Anastasia Kvasha at the 6th International Disaster and Risk Conference IDRC "Integrative Risk Management – towards resilient cities", held in Davos (Switzerland) on 28 August - 01 September 2016.