# Evaluation of Different Simulation Methods for Analyzing Flood Scenarios in the Danube Delta
## 5 Discussion
The results obtained from the application of the dynamic method identified flooding areas and water depths close to the settlements in the situation of maintaining the breach in the dyke for a period of 24 h.  
This method is much more complex than the static method, as it requires a wider range of specific data and knowledge from the operator. If the main concern is to anticipate the current or future behaviour, obtaining relevant field data is an important and integral part of the modeling process [36]. Good results depend on the exact formulation of the problem, and the correct identification of the main parameters that influence the investigated phenomena. Analysing the most unfavorable scenario (flood stage IV-maximum water level), there were several floodable surfaces inside the settlements (Table 5). For the dynamic method the modeled flooded area was calculated using ArcGIS software. From RAS Mapper-Animator, it was found that the maximum flooded areas at flood stage IV was 5.79 km\({}^{2}\) (for all settlements), the simulation taking place between 10:00 of 6 July 2010 and 10:00 of 7 July 2010. The flood surface depth reached up to 1.94 m (flood stage IV Partizani settlement), 1.85 m (flood stage IV Ilganii de Sus), 1.91 m (flood stage IV Vulturu settlement), 1.89 m (flood stage IV Gorgova settlement), 1.66 m (flood stage IV Mila 23 settlement), 1.90 m (Gorgova settlement), 1.95 m (Crisansettlement), and 1.47 m (Sulina settlement). Figure 13: Flood scenarios maps for Crisan (first column group of subfigures) and Sulina (second column group of subfigures) settlements, corresponding to the condition of 7 July 2010, by using the 1D/2D HEC-RAS model, at high resolution DTM 0.5 m \(\times\) 0.5 m, dynamic method. Figures 12-14 indicate that the areas flooded under the four flood stages in the dynamic method, varied between 0.8 km\({}^{2}\)-1.68 km\({}^{2}\) (Partizani), 0.26 km\({}^{2}\)-0.49 km\({}^{2}\) (Ilganii de Sus), 0.80 km\({}^{2}\)-0.33 km\({}^{2}\) (Vulturu), 0.025 km\({}^{2}\)-0.18 km\({}^{2}\) (Maliuc), 0.8 km\({}^{2}\)-0.71 km\({}^{2}\) (Gorgova), 0.21 km\({}^{2}\)-0.77 km\({}^{2}\) (Mila 23), 0.05 km\({}^{2}\)-0.34 km\({}^{2}\) (Crisan), and 0.15 km\({}^{2}\)-1.29 km\({}^{2}\) (Sulina). From the results of the simulations performed we noticed that the flood extension covered households, infrastructure elements, and vacant land in different proportions from one flood stage to another. It can be seen in Figures 11-13 that water flows in localities from one zone to another, following the slope of the natural topography. The widespread use and role of hydraulic models have changed in the recent years, mainly due to the significant advances in computer modeling. They remain an important modeling tool, especially in the design of hydraulic, river structures, and coastal engineering applications, as well as for environmental protection, or in providing physical input data for mathematical modeling [46]. Figure 14 shows the results of the static method. The results are presented in the form of flooding maps that represent the potentially floodable areas of the analyzed settlements in the Danube Delta at flood stage IV (the maximum water level), in the situation of maintaining the breach in the dyke for more than 24 h.  
The results obtained following the application of the static method highlight the flood surfaces in the settlements corresponding to the maximum water level of the Danube, this situation being the most unfavorable (the water level on the Danube being the same as the water level in the localities targeted, by keeping the breach in the protective dam for a longer period). This method is less complex than the  
Figure 14: The representation of digital maps with flooded areas for settlements: (**a**)—Partizani, (**b**)—Crisan, (**c**)—Maliuc, (**d**)—Ilganii de sus, (**e**)—Gorgova, (**f**)—Vulturu, (**g**)—Sulina, (**h**)—Mila 23, by using GIS analysis, at high resolution DTM 0.5 m \(\times\) 0.5 m, static method.