# Evaluation of Different Simulation Methods for Analyzing Flood Scenarios in the Danube Delta
## 5 Discussion
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{3}{*}{**Settlement**} & **Maximum** & \multicolumn{3}{c}{**Dynamic Method**} & \multicolumn{3}{c}{**Static Method**} \\ \cline{3-8}  & **Water Level** & **Floodage** & **Floodage** & **Floodage** & **Floodage** & **Floodage** \\  & **Flood Stage** & **Surfaces** & **Areas** & **Surfaces** & **Areas** & **\%** \\  & **IV** & **(km\({}^{2}\))** & **(\%)** & **(km\({}^{2}\))** & **(\%)** & **(\%)** \\ \hline Partizani & 4.32 m BS75 & 1.68 & 93.92\% & 1.76 & 98.39\% & 4.47\% \\ Ilganii de Sus & 4.32 m BS75 & 0.49 & 87.81\% & 0.54 & 96.77\% & 8.96\% \\ Vulturu & 3.61 m BS75 & 0.33 & 79.44\% & 0.40 & 96.29\% & 16.85\% \\ Maliuc & 3.43 m BS75 & 0.18 & 82.57\% & 0.20 & 91.74\% & 9.17\% \\ Gorgova & 3.11 m BS75 & 0.71 & 87.22\% & 0.75 & 92.14\% & 4.92\% \\ Mila 23 & 2.70 m BS75 & 0.77 & 82.53\% & 0.86 & 92.18\% & 9.65\% \\ Crisan & 2.10 m BS75 & 0.34 & 71.03\% & 0.40 & 83.56\% & 12.53\% \\ Sulina & 1.24 m BS75 & 1.29 & 63.58\% & 1.60 & 78.86\% & 15.28\% \\ \hline \hline \end{tabular}
\end{table} 
Table 5: The flooded areas of the settlements analyzed at the flood stage IV: maximum water level of the Danube. dynamic method, as it requires a smaller set of specific data and knowledge from the operator. By the analysis of the most unfavorable scenario, floodable surfaces inside the localities resulted, and they are presented in Table 5.  
The differences between the two methods are summarized in Table 5. For the static method the flooded area was calculated using Global Mapper software. From the software, it was found that the maximum flooded areas at flood stage IV was 6.51 km\({}^{2}\). The flood surface depth reached up to 4.08 m (flood stage IV Partizani settlement), 3.46 m (flood stage IV Ilganii de Sus), 2.85 m (flood stage IV Vulturu settlement), 2.64 m (flood stage IV Gorgova settlement), 2.61 m (flood stage IV Mila 23 settlement), 2.59 m (Gorgova settlement), 2.06 m (Crisansettlement), and 1.65 m (Sulina settlement). For some settlements the differences were significant, considering that the second method (static) involved maintaining the breach for a long enough time to flood at maximum levels all areas below this level within the settlements. In the case of the first method's (dynamic) analysis, with 1D/2D hydraulic modeling, the actual flooded surfaces were determined for a shorter period (24 h), resulting in smaller flooded surfaces. Following the comparative results (applying flooding stage IV-maximum water level), it can be observed that 75% of localities (6 out of 8) had more than 91% of their surface flooded, if the breaches were maintained for more than a day in the dykes of the settlements, and at maximum water levels of the Danube. In the case of maintaining the breaches for a period of only 1 day, it was observed that only one out of eight settlements considered had a flooded area of more than 90%. In the application of the two methods, for some of the settlements, slightly bigger differences were noticed regarding the flooded surface. The most significant differences appeared for the settlements Vulturu, Crisan, and Sulina, with differences exceeding 12%, and reaching up to approximately 17% in some cases. In order to analyze, in percentage, the differences regarding the flooded areas in all the other flood stages (flood stage I, flood stage II, and flood stage III), some graphs were designed, showing the dynamics of the flooded areas in the scenarios analyzed for the settlements (Figures 15 and 16). The dynamics of the flooded areas for the analyzed settlements differed from one method to the other. From the displayed results, it is visible that by applying the static method in all flood stages, the flooded surfaces were larger compared to the flooded surfaces obtained by applying the dynamic method.